Moved software rasterizer functionality to new directory.

1 files changed, 2539 insertions, 0 deletions

diff --git a/src/mesa/swrast/s_texture.c b/src/mesa/swrast/s_texture.c
new file mode 100644
index 0000000000..04f8645b97
--- /dev/null
+++ b/src/mesa/swrast/s_texture.c
@@ -0,0 +1,2539 @@
+/* $Id: s_texture.c,v 1.1 2000/10/31 18:00:04 keithw Exp $ */
+
+/*
+ * Mesa 3-D graphics library
+ * Version:  3.5
+ * 
+ * Copyright (C) 1999-2000  Brian Paul   All Rights Reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+
+#include "glheader.h"
+#include "context.h"
+#include "colormac.h"
+#include "macros.h"
+#include "mmath.h"
+#include "mem.h"
+#include "teximage.h"
+
+#include "s_pb.h"
+#include "s_texture.h"
+
+
+
+
+/*
+ * Paletted texture sampling.
+ * Input:  tObj - the texture object
+ *         index - the palette index (8-bit only)
+ * Output:  red, green, blue, alpha - the texel color
+ */
+static void palette_sample(const struct gl_texture_object *tObj,
+                           GLint index, GLchan rgba[4] )
+{
+   GLcontext *ctx = _mesa_get_current_context();  /* THIS IS A HACK */
+   const GLchan *palette;
+   GLenum format;
+
+   if (ctx->Texture.SharedPalette) {
+      ASSERT(!ctx->Texture.Palette.FloatTable);
+      palette = (const GLchan *) ctx->Texture.Palette.Table;
+      format = ctx->Texture.Palette.Format;
+   }
+   else {
+      ASSERT(!tObj->Palette.FloatTable);
+      palette = (const GLchan *) tObj->Palette.Table;
+      format = tObj->Palette.Format;
+   }
+
+   switch (format) {
+      case GL_ALPHA:
+         rgba[ACOMP] = palette[index];
+         return;
+      case GL_LUMINANCE:
+      case GL_INTENSITY:
+         rgba[RCOMP] = palette[index];
+         return;
+      case GL_LUMINANCE_ALPHA:
+         rgba[RCOMP] = palette[(index << 1) + 0];
+         rgba[ACOMP] = palette[(index << 1) + 1];
+         return;
+      case GL_RGB:
+         rgba[RCOMP] = palette[index * 3 + 0];
+         rgba[GCOMP] = palette[index * 3 + 1];
+         rgba[BCOMP] = palette[index * 3 + 2];
+         return;
+      case GL_RGBA:
+         rgba[RCOMP] = palette[(index << 2) + 0];
+         rgba[GCOMP] = palette[(index << 2) + 1];
+         rgba[BCOMP] = palette[(index << 2) + 2];
+         rgba[ACOMP] = palette[(index << 2) + 3];
+         return;
+      default:
+         gl_problem(NULL, "Bad palette format in palette_sample");
+   }
+}
+
+
+
+/*
+ * These values are used in the fixed-point arithmetic used
+ * for linear filtering.
+ */
+#define WEIGHT_SCALE 65536.0F
+#define WEIGHT_SHIFT 16
+
+
+/*
+ * Used to compute texel locations for linear sampling.
+ */
+#define COMPUTE_LINEAR_TEXEL_LOCATIONS(wrapMode, S, U, SIZE, I0, I1)	\
+{									\
+   if (wrapMode == GL_REPEAT) {						\
+      U = S * SIZE - 0.5F;						\
+      I0 = ((GLint) myFloor(U)) & (SIZE - 1);				\
+      I1 = (I0 + 1) & (SIZE - 1);					\
+   }									\
+   else {								\
+      U = S * SIZE;							\
+      if (U < 0.0F)							\
+         U = 0.0F;							\
+      else if (U >= SIZE)						\
+         U = SIZE;							\
+      U -= 0.5F;							\
+      I0 = (GLint) myFloor(U);						\
+      I1 = I0 + 1;							\
+      if (wrapMode == GL_CLAMP_TO_EDGE) {				\
+         if (I0 < 0)							\
+            I0 = 0;							\
+         if (I1 >= SIZE)						\
+            I1 = SIZE - 1;						\
+      }									\
+   }									\
+}
+
+
+/*
+ * Used to compute texel location for nearest sampling.
+ */
+#define COMPUTE_NEAREST_TEXEL_LOCATION(wrapMode, S, SIZE, I)		\
+{									\
+   if (wrapMode == GL_REPEAT) {						\
+      /* s limited to [0,1) */						\
+      /* i limited to [0,width-1] */					\
+      I = (GLint) (S * SIZE);						\
+      if (S < 0.0F)							\
+         I -= 1;							\
+      I &= (SIZE - 1);							\
+   }									\
+   else if (wrapMode == GL_CLAMP_TO_EDGE) {				\
+      const GLfloat min = 1.0F / (2.0F * SIZE);				\
+      const GLfloat max = 1.0F - min;					\
+      if (S < min)							\
+         I = 0;								\
+      else if (S > max)							\
+         I = SIZE - 1;							\
+      else								\
+         I = (GLint) (S * SIZE);					\
+   }									\
+   else {								\
+      ASSERT(wrapMode == GL_CLAMP);					\
+      /* s limited to [0,1] */						\
+      /* i limited to [0,width-1] */					\
+      if (S <= 0.0F)							\
+         I = 0;								\
+      else if (S >= 1.0F)						\
+         I = SIZE - 1;							\
+      else								\
+         I = (GLint) (S * SIZE);					\
+   }									\
+}
+
+
+/*
+ * Compute linear mipmap levels for given lambda.
+ */
+#define COMPUTE_LINEAR_MIPMAP_LEVEL(tObj, lambda, level)	\
+{								\
+   if (lambda < 0.0F)						\
+      lambda = 0.0F;						\
+   else if (lambda > tObj->M)					\
+      lambda = tObj->M;						\
+   level = (GLint) (tObj->BaseLevel + lambda);			\
+}
+
+
+/*
+ * Compute nearest mipmap level for given lambda.
+ */
+#define COMPUTE_NEAREST_MIPMAP_LEVEL(tObj, lambda, level)	\
+{								\
+   if (lambda <= 0.5F)						\
+      lambda = 0.0F;						\
+   else if (lambda > tObj->M + 0.4999F)				\
+      lambda = tObj->M + 0.4999F;				\
+   level = (GLint) (tObj->BaseLevel + lambda + 0.5F);		\
+   if (level > tObj->P)						\
+      level = tObj->P;						\
+}
+
+
+   
+
+/*
+ * Bitflags for texture border color sampling.
+ */
+#define I0BIT   1
+#define I1BIT   2
+#define J0BIT   4
+#define J1BIT   8
+#define K0BIT  16
+#define K1BIT  32
+
+
+
+/**********************************************************************/
+/*                    1-D Texture Sampling Functions                  */
+/**********************************************************************/
+
+
+/*
+ * Return floor of x, being careful of negative values.
+ */
+static GLfloat myFloor(GLfloat x)
+{
+   if (x < 0.0F)
+      return (GLfloat) ((GLint) x - 1);
+   else
+      return (GLfloat) (GLint) x;
+}
+
+
+/*
+ * Return the fractional part of x.
+ */
+#define myFrac(x)  ( (x) - myFloor(x) )
+
+
+
+
+/*
+ * Given 1-D texture image and an (i) texel column coordinate, return the
+ * texel color.
+ */
+static void get_1d_texel( const struct gl_texture_object *tObj,
+                          const struct gl_texture_image *img, GLint i,
+                          GLchan rgba[4] )
+{
+   const GLchan *texel;
+
+#ifdef DEBUG
+   GLint width = img->Width;
+   assert(i >= 0);
+   assert(i < width);
+#endif
+
+   switch (img->Format) {
+      case GL_COLOR_INDEX:
+         {
+            GLint index = img->Data[i];
+            palette_sample(tObj, index, rgba);
+            return;
+         }
+      case GL_ALPHA:
+         rgba[ACOMP] = img->Data[ i ];
+         return;
+      case GL_LUMINANCE:
+      case GL_INTENSITY:
+         rgba[RCOMP] = img->Data[ i ];
+         return;
+      case GL_LUMINANCE_ALPHA:
+         texel = img->Data + i * 2;
+         rgba[RCOMP] = texel[0];
+         rgba[ACOMP] = texel[1];
+         return;
+      case GL_RGB:
+         texel = img->Data + i * 3;
+         rgba[RCOMP] = texel[0];
+         rgba[GCOMP] = texel[1];
+         rgba[BCOMP] = texel[2];
+         return;
+      case GL_RGBA:
+         texel = img->Data + i * 4;
+         rgba[RCOMP] = texel[0];
+         rgba[GCOMP] = texel[1];
+         rgba[BCOMP] = texel[2];
+         rgba[ACOMP] = texel[3];
+         return;
+      default:
+         gl_problem(NULL, "Bad format in get_1d_texel");
+         return;
+   }
+}
+
+
+
+/*
+ * Return the texture sample for coordinate (s) using GL_NEAREST filter.
+ */
+static void sample_1d_nearest( const struct gl_texture_object *tObj,
+                               const struct gl_texture_image *img,
+                               GLfloat s, GLchan rgba[4] )
+{
+   const GLint width = img->Width2;  /* without border, power of two */
+   const GLchan *texel;
+   GLint i;
+
+   COMPUTE_NEAREST_TEXEL_LOCATION(tObj->WrapS, s, width, i);
+
+   /* skip over the border, if any */
+   i += img->Border;
+
+   /* Get the texel */
+   switch (img->Format) {
+      case GL_COLOR_INDEX:
+         {
+            GLint index = img->Data[i];
+            palette_sample(tObj, index, rgba );
+            return;
+         }
+      case GL_ALPHA:
+         rgba[ACOMP] = img->Data[i];
+         return;
+      case GL_LUMINANCE:
+      case GL_INTENSITY:
+         rgba[RCOMP] = img->Data[i];
+         return;
+      case GL_LUMINANCE_ALPHA:
+         texel = img->Data + i * 2;
+         rgba[RCOMP] = texel[0];
+         rgba[ACOMP] = texel[1];
+         return;
+      case GL_RGB:
+         texel = img->Data + i * 3;
+         rgba[RCOMP] = texel[0];
+         rgba[GCOMP] = texel[1];
+         rgba[BCOMP] = texel[2];
+         return;
+      case GL_RGBA:
+         texel = img->Data + i * 4;
+         rgba[RCOMP] = texel[0];
+         rgba[GCOMP] = texel[1];
+         rgba[BCOMP] = texel[2];
+         rgba[ACOMP] = texel[3];
+         return;
+      default:
+         gl_problem(NULL, "Bad format in sample_1d_nearest");
+   }
+}
+
+
+
+/*
+ * Return the texture sample for coordinate (s) using GL_LINEAR filter.
+ */
+static void sample_1d_linear( const struct gl_texture_object *tObj,
+                              const struct gl_texture_image *img,
+                              GLfloat s,
+                              GLchan rgba[4] )
+{
+   const GLint width = img->Width2;
+   GLint i0, i1;
+   GLfloat u;
+   GLuint useBorderColor;
+
+   COMPUTE_LINEAR_TEXEL_LOCATIONS(tObj->WrapS, s, u, width, i0, i1);
+
+   useBorderColor = 0;
+   if (img->Border) {
+      i0 += img->Border;
+      i1 += img->Border;
+   }
+   else {
+      if (i0 < 0 || i0 >= width)   useBorderColor |= I0BIT;
+      if (i1 < 0 || i1 >= width)   useBorderColor |= I1BIT;
+   }
+
+   {
+      const GLfloat a = myFrac(u);
+      /* compute sample weights in fixed point in [0,WEIGHT_SCALE] */
+      const GLint w0 = (GLint) ((1.0F-a) * WEIGHT_SCALE + 0.5F);
+      const GLint w1 = (GLint) (      a  * WEIGHT_SCALE + 0.5F);
+
+      GLchan t0[4], t1[4];  /* texels */
+
+      if (useBorderColor & I0BIT) {
+         COPY_CHAN4(t0, tObj->BorderColor);
+      }
+      else {
+         get_1d_texel( tObj, img, i0, t0 );
+      }
+      if (useBorderColor & I1BIT) {
+         COPY_CHAN4(t1, tObj->BorderColor);
+      }
+      else {
+         get_1d_texel( tObj, img, i1, t1 );
+      }
+
+      rgba[0] = (GLchan) ((w0 * t0[0] + w1 * t1[0]) >> WEIGHT_SHIFT);
+      rgba[1] = (GLchan) ((w0 * t0[1] + w1 * t1[1]) >> WEIGHT_SHIFT);
+      rgba[2] = (GLchan) ((w0 * t0[2] + w1 * t1[2]) >> WEIGHT_SHIFT);
+      rgba[3] = (GLchan) ((w0 * t0[3] + w1 * t1[3]) >> WEIGHT_SHIFT);
+   }
+}
+
+
+static void
+sample_1d_nearest_mipmap_nearest( const struct gl_texture_object *tObj,
+                                  GLfloat s, GLfloat lambda,
+                                  GLchan rgba[4] )
+{
+   GLint level;
+   COMPUTE_NEAREST_MIPMAP_LEVEL(tObj, lambda, level);
+   sample_1d_nearest( tObj, tObj->Image[level], s, rgba );
+}
+
+
+static void
+sample_1d_linear_mipmap_nearest( const struct gl_texture_object *tObj,
+                                 GLfloat s, GLfloat lambda,
+                                 GLchan rgba[4] )
+{
+   GLint level;
+   COMPUTE_NEAREST_MIPMAP_LEVEL(tObj, lambda, level);
+   sample_1d_linear( tObj, tObj->Image[level], s, rgba );
+}
+
+
+
+static void
+sample_1d_nearest_mipmap_linear( const struct gl_texture_object *tObj,
+                                 GLfloat s, GLfloat lambda,
+                                 GLchan rgba[4] )
+{
+   GLint level;
+
+   COMPUTE_LINEAR_MIPMAP_LEVEL(tObj, lambda, level);
+
+   if (level >= tObj->P) {
+      sample_1d_nearest( tObj, tObj->Image[tObj->P], s, rgba );
+   }
+   else {
+      GLchan t0[4], t1[4];
+      const GLfloat f = myFrac(lambda);
+      sample_1d_nearest( tObj, tObj->Image[level  ], s, t0 );
+      sample_1d_nearest( tObj, tObj->Image[level+1], s, t1 );
+      rgba[RCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[RCOMP] + f * t1[RCOMP]);
+      rgba[GCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[GCOMP] + f * t1[GCOMP]);
+      rgba[BCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[BCOMP] + f * t1[BCOMP]);
+      rgba[ACOMP] = (GLchan) (GLint) ((1.0F-f) * t0[ACOMP] + f * t1[ACOMP]);
+   }
+}
+
+
+
+static void
+sample_1d_linear_mipmap_linear( const struct gl_texture_object *tObj,
+                                GLfloat s, GLfloat lambda,
+                                GLchan rgba[4] )
+{
+   GLint level;
+
+   COMPUTE_LINEAR_MIPMAP_LEVEL(tObj, lambda, level);
+
+   if (level >= tObj->P) {
+      sample_1d_linear( tObj, tObj->Image[tObj->P], s, rgba );
+   }
+   else {
+      GLchan t0[4], t1[4];
+      const GLfloat f = myFrac(lambda);
+      sample_1d_linear( tObj, tObj->Image[level  ], s, t0 );
+      sample_1d_linear( tObj, tObj->Image[level+1], s, t1 );
+      rgba[RCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[RCOMP] + f * t1[RCOMP]);
+      rgba[GCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[GCOMP] + f * t1[GCOMP]);
+      rgba[BCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[BCOMP] + f * t1[BCOMP]);
+      rgba[ACOMP] = (GLchan) (GLint) ((1.0F-f) * t0[ACOMP] + f * t1[ACOMP]);
+   }
+}
+
+
+
+static void sample_nearest_1d( const struct gl_texture_object *tObj, GLuint n,
+                               const GLfloat s[], const GLfloat t[],
+                               const GLfloat u[], const GLfloat lambda[],
+                               GLchan rgba[][4] )
+{
+   GLuint i;
+   struct gl_texture_image *image = tObj->Image[tObj->BaseLevel];
+   (void) t;
+   (void) u;
+   (void) lambda;
+   for (i=0;i<n;i++) {
+      sample_1d_nearest( tObj, image, s[i], rgba[i] );
+   }
+}
+
+
+
+static void sample_linear_1d( const struct gl_texture_object *tObj, GLuint n,
+                              const GLfloat s[], const GLfloat t[],
+                              const GLfloat u[], const GLfloat lambda[],
+                              GLchan rgba[][4] )
+{
+   GLuint i;
+   struct gl_texture_image *image = tObj->Image[tObj->BaseLevel];
+   (void) t;
+   (void) u;
+   (void) lambda;
+   for (i=0;i<n;i++) {
+      sample_1d_linear( tObj, image, s[i], rgba[i] );
+   }
+}
+
+
+/*
+ * Given an (s) texture coordinate and lambda (level of detail) value,
+ * return a texture sample.
+ *
+ */
+static void sample_lambda_1d( const struct gl_texture_object *tObj, GLuint n,
+                              const GLfloat s[], const GLfloat t[],
+                              const GLfloat u[], const GLfloat lambda[],
+                              GLchan rgba[][4] )
+{
+   GLuint i;
+
+   (void) t;
+   (void) u;
+
+   for (i=0;i<n;i++) {
+      if (lambda[i] > tObj->MinMagThresh) {
+         /* minification */
+         switch (tObj->MinFilter) {
+            case GL_NEAREST:
+               sample_1d_nearest( tObj, tObj->Image[tObj->BaseLevel], s[i], rgba[i] );
+               break;
+            case GL_LINEAR:
+               sample_1d_linear( tObj, tObj->Image[tObj->BaseLevel], s[i], rgba[i] );
+               break;
+            case GL_NEAREST_MIPMAP_NEAREST:
+               sample_1d_nearest_mipmap_nearest( tObj, lambda[i], s[i], rgba[i] );
+               break;
+            case GL_LINEAR_MIPMAP_NEAREST:
+               sample_1d_linear_mipmap_nearest( tObj, s[i], lambda[i], rgba[i] );
+               break;
+            case GL_NEAREST_MIPMAP_LINEAR:
+               sample_1d_nearest_mipmap_linear( tObj, s[i], lambda[i], rgba[i] );
+               break;
+            case GL_LINEAR_MIPMAP_LINEAR:
+               sample_1d_linear_mipmap_linear( tObj, s[i], lambda[i], rgba[i] );
+               break;
+            default:
+               gl_problem(NULL, "Bad min filter in sample_1d_texture");
+               return;
+         }
+      }
+      else {
+         /* magnification */
+         switch (tObj->MagFilter) {
+            case GL_NEAREST:
+               sample_1d_nearest( tObj, tObj->Image[tObj->BaseLevel], s[i], rgba[i] );
+               break;
+            case GL_LINEAR:
+               sample_1d_linear( tObj, tObj->Image[tObj->BaseLevel], s[i], rgba[i] );
+               break;
+            default:
+               gl_problem(NULL, "Bad mag filter in sample_1d_texture");
+               return;
+         }
+      }
+   }
+}
+
+
+
+
+/**********************************************************************/
+/*                    2-D Texture Sampling Functions                  */
+/**********************************************************************/
+
+
+/*
+ * Given a texture image and an (i,j) integer texel coordinate, return the
+ * texel color.
+ */
+static void get_2d_texel( const struct gl_texture_object *tObj,
+                          const struct gl_texture_image *img, GLint i, GLint j,
+                          GLchan rgba[4] )
+{
+   const GLint width = img->Width;    /* includes border */
+   const GLchan *texel;
+
+#ifdef DEBUG
+   const GLint height = img->Height;  /* includes border */
+   assert(i >= 0);
+   assert(i < width);
+   assert(j >= 0);
+   assert(j < height);
+#endif
+
+   switch (img->Format) {
+      case GL_COLOR_INDEX:
+         {
+            GLint index = img->Data[ width *j + i ];
+            palette_sample(tObj, index, rgba );
+            return;
+         }
+      case GL_ALPHA:
+         rgba[ACOMP] = img->Data[ width * j + i ];
+         return;
+      case GL_LUMINANCE:
+      case GL_INTENSITY:
+         rgba[RCOMP] = img->Data[ width * j + i ];
+         return;
+      case GL_LUMINANCE_ALPHA:
+         texel = img->Data + (width * j + i) * 2;
+         rgba[RCOMP] = texel[0];
+         rgba[ACOMP] = texel[1];
+         return;
+      case GL_RGB:
+         texel = img->Data + (width * j + i) * 3;
+         rgba[RCOMP] = texel[0];
+         rgba[GCOMP] = texel[1];
+         rgba[BCOMP] = texel[2];
+         return;
+      case GL_RGBA:
+         texel = img->Data + (width * j + i) * 4;
+         rgba[RCOMP] = texel[0];
+         rgba[GCOMP] = texel[1];
+         rgba[BCOMP] = texel[2];
+         rgba[ACOMP] = texel[3];
+         return;
+      default:
+         gl_problem(NULL, "Bad format in get_2d_texel");
+   }
+}
+
+
+
+/*
+ * Return the texture sample for coordinate (s,t) using GL_NEAREST filter.
+ */
+static void sample_2d_nearest( const struct gl_texture_object *tObj,
+                               const struct gl_texture_image *img,
+                               GLfloat s, GLfloat t,
+                               GLchan rgba[] )
+{
+   const GLint imgWidth = img->Width;  /* includes border */
+   const GLint width = img->Width2;    /* without border, power of two */
+   const GLint height = img->Height2;  /* without border, power of two */
+   const GLchan *texel;
+   GLint i, j;
+
+   COMPUTE_NEAREST_TEXEL_LOCATION(tObj->WrapS, s, width,  i);
+   COMPUTE_NEAREST_TEXEL_LOCATION(tObj->WrapT, t, height, j);
+
+   /* skip over the border, if any */
+   i += img->Border;
+   j += img->Border;
+
+   switch (img->Format) {
+      case GL_COLOR_INDEX:
+         {
+            GLint index = img->Data[ j * imgWidth + i ];
+            palette_sample(tObj, index, rgba);
+            return;
+         }
+      case GL_ALPHA:
+         rgba[ACOMP] = img->Data[ j * imgWidth + i ];
+         return;
+      case GL_LUMINANCE:
+      case GL_INTENSITY:
+         rgba[RCOMP] = img->Data[ j * imgWidth + i ];
+         return;
+      case GL_LUMINANCE_ALPHA:
+         texel = img->Data + ((j * imgWidth + i) << 1);
+         rgba[RCOMP] = texel[0];
+         rgba[ACOMP] = texel[1];
+         return;
+      case GL_RGB:
+         texel = img->Data + (j * imgWidth + i) * 3;
+         rgba[RCOMP] = texel[0];
+         rgba[GCOMP] = texel[1];
+         rgba[BCOMP] = texel[2];
+         return;
+      case GL_RGBA:
+         texel = img->Data + ((j * imgWidth + i) << 2);
+         rgba[RCOMP] = texel[0];
+         rgba[GCOMP] = texel[1];
+         rgba[BCOMP] = texel[2];
+         rgba[ACOMP] = texel[3];
+         return;
+      default:
+         gl_problem(NULL, "Bad format in sample_2d_nearest");
+   }
+}
+
+
+
+/*
+ * Return the texture sample for coordinate (s,t) using GL_LINEAR filter.
+ * New sampling code contributed by Lynn Quam <quam@ai.sri.com>.
+ */
+static void sample_2d_linear( const struct gl_texture_object *tObj,
+                              const struct gl_texture_image *img,
+                              GLfloat s, GLfloat t,
+                              GLchan rgba[] )
+{
+   const GLint width = img->Width2;
+   const GLint height = img->Height2;
+   GLint i0, j0, i1, j1;
+   GLuint useBorderColor;
+   GLfloat u, v;
+
+   COMPUTE_LINEAR_TEXEL_LOCATIONS(tObj->WrapS, s, u, width,  i0, i1);
+   COMPUTE_LINEAR_TEXEL_LOCATIONS(tObj->WrapT, t, v, height, j0, j1);
+
+   useBorderColor = 0;
+   if (img->Border) {
+      i0 += img->Border;
+      i1 += img->Border;
+      j0 += img->Border;
+      j1 += img->Border;
+   }
+   else {
+      if (i0 < 0 || i0 >= width)   useBorderColor |= I0BIT;
+      if (i1 < 0 || i1 >= width)   useBorderColor |= I1BIT;
+      if (j0 < 0 || j0 >= height)  useBorderColor |= J0BIT;
+      if (j1 < 0 || j1 >= height)  useBorderColor |= J1BIT;
+   }
+
+   {
+      const GLfloat a = myFrac(u);
+      const GLfloat b = myFrac(v);
+      /* compute sample weights in fixed point in [0,WEIGHT_SCALE] */
+      const GLint w00 = (GLint) ((1.0F-a)*(1.0F-b) * WEIGHT_SCALE + 0.5F);
+      const GLint w10 = (GLint) (      a *(1.0F-b) * WEIGHT_SCALE + 0.5F);
+      const GLint w01 = (GLint) ((1.0F-a)*      b  * WEIGHT_SCALE + 0.5F);
+      const GLint w11 = (GLint) (      a *      b  * WEIGHT_SCALE + 0.5F);
+      GLchan t00[4];
+      GLchan t10[4];
+      GLchan t01[4];
+      GLchan t11[4];
+
+      if (useBorderColor & (I0BIT | J0BIT)) {
+         COPY_CHAN4(t00, tObj->BorderColor);
+      }
+      else {
+         get_2d_texel( tObj, img, i0, j0, t00 );
+      }
+      if (useBorderColor & (I1BIT | J0BIT)) {
+         COPY_CHAN4(t10, tObj->BorderColor);
+      }
+      else {
+         get_2d_texel( tObj, img, i1, j0, t10 );
+      }
+      if (useBorderColor & (I0BIT | J1BIT)) {
+         COPY_CHAN4(t01, tObj->BorderColor);
+      }
+      else {
+         get_2d_texel( tObj, img, i0, j1, t01 );
+      }
+      if (useBorderColor & (I1BIT | J1BIT)) {
+         COPY_CHAN4(t11, tObj->BorderColor);
+      }
+      else {
+         get_2d_texel( tObj, img, i1, j1, t11 );
+      }
+
+      rgba[0] = (GLchan) ((w00 * t00[0] + w10 * t10[0] + w01 * t01[0] + w11 * t11[0]) >> WEIGHT_SHIFT);
+      rgba[1] = (GLchan) ((w00 * t00[1] + w10 * t10[1] + w01 * t01[1] + w11 * t11[1]) >> WEIGHT_SHIFT);
+      rgba[2] = (GLchan) ((w00 * t00[2] + w10 * t10[2] + w01 * t01[2] + w11 * t11[2]) >> WEIGHT_SHIFT);
+      rgba[3] = (GLchan) ((w00 * t00[3] + w10 * t10[3] + w01 * t01[3] + w11 * t11[3]) >> WEIGHT_SHIFT);
+   }
+
+}
+
+
+
+static void
+sample_2d_nearest_mipmap_nearest( const struct gl_texture_object *tObj,
+                                  GLfloat s, GLfloat t, GLfloat lambda,
+                                  GLchan rgba[4] )
+{
+   GLint level;
+   COMPUTE_NEAREST_MIPMAP_LEVEL(tObj, lambda, level);
+   sample_2d_nearest( tObj, tObj->Image[level], s, t, rgba );
+}
+
+
+
+static void
+sample_2d_linear_mipmap_nearest( const struct gl_texture_object *tObj,
+                                 GLfloat s, GLfloat t, GLfloat lambda,
+                                 GLchan rgba[4] )
+{
+   GLint level;
+   COMPUTE_NEAREST_MIPMAP_LEVEL(tObj, lambda, level);
+   sample_2d_linear( tObj, tObj->Image[level], s, t, rgba );
+}
+
+
+
+static void
+sample_2d_nearest_mipmap_linear( const struct gl_texture_object *tObj,
+                                 GLfloat s, GLfloat t, GLfloat lambda,
+                                 GLchan rgba[4] )
+{
+   GLint level;
+
+   COMPUTE_LINEAR_MIPMAP_LEVEL(tObj, lambda, level);
+
+   if (level >= tObj->P) {
+      sample_2d_nearest( tObj, tObj->Image[tObj->P], s, t, rgba );
+   }
+   else {
+      GLchan t0[4], t1[4];  /* texels */
+      const GLfloat f = myFrac(lambda);
+      sample_2d_nearest( tObj, tObj->Image[level  ], s, t, t0 );
+      sample_2d_nearest( tObj, tObj->Image[level+1], s, t, t1 );
+      rgba[RCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[RCOMP] + f * t1[RCOMP]);
+      rgba[GCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[GCOMP] + f * t1[GCOMP]);
+      rgba[BCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[BCOMP] + f * t1[BCOMP]);
+      rgba[ACOMP] = (GLchan) (GLint) ((1.0F-f) * t0[ACOMP] + f * t1[ACOMP]);
+   }
+}
+
+
+
+static void
+sample_2d_linear_mipmap_linear( const struct gl_texture_object *tObj,
+                                GLfloat s, GLfloat t, GLfloat lambda,
+                                GLchan rgba[4] )
+{
+   GLint level;
+
+   COMPUTE_LINEAR_MIPMAP_LEVEL(tObj, lambda, level);
+
+   if (level >= tObj->P) {
+      sample_2d_linear( tObj, tObj->Image[tObj->P], s, t, rgba );
+   }
+   else {
+      GLchan t0[4], t1[4];  /* texels */
+      const GLfloat f = myFrac(lambda);
+      sample_2d_linear( tObj, tObj->Image[level  ], s, t, t0 );
+      sample_2d_linear( tObj, tObj->Image[level+1], s, t, t1 );
+      rgba[RCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[RCOMP] + f * t1[RCOMP]);
+      rgba[GCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[GCOMP] + f * t1[GCOMP]);
+      rgba[BCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[BCOMP] + f * t1[BCOMP]);
+      rgba[ACOMP] = (GLchan) (GLint) ((1.0F-f) * t0[ACOMP] + f * t1[ACOMP]);
+   }
+}
+
+
+
+static void sample_nearest_2d( const struct gl_texture_object *tObj, GLuint n,
+                               const GLfloat s[], const GLfloat t[],
+                               const GLfloat u[], const GLfloat lambda[],
+                               GLchan rgba[][4] )
+{
+   GLuint i;
+   struct gl_texture_image *image = tObj->Image[tObj->BaseLevel];
+   (void) u;
+   (void) lambda;
+   for (i=0;i<n;i++) {
+      sample_2d_nearest( tObj, image, s[i], t[i], rgba[i] );
+   }
+}
+
+
+
+static void sample_linear_2d( const struct gl_texture_object *tObj, GLuint n,
+                              const GLfloat s[], const GLfloat t[],
+                              const GLfloat u[], const GLfloat lambda[],
+                              GLchan rgba[][4] )
+{
+   GLuint i;
+   struct gl_texture_image *image = tObj->Image[tObj->BaseLevel];
+   (void) u;
+   (void) lambda;
+   for (i=0;i<n;i++) {
+      sample_2d_linear( tObj, image, s[i], t[i], rgba[i] );
+   }
+}
+
+
+/*
+ * Given an (s,t) texture coordinate and lambda (level of detail) value,
+ * return a texture sample.
+ */
+static void sample_lambda_2d( const struct gl_texture_object *tObj,
+                              GLuint n,
+                              const GLfloat s[], const GLfloat t[],
+                              const GLfloat u[], const GLfloat lambda[],
+                              GLchan rgba[][4] )
+{
+   GLuint i;
+   (void) u;
+   for (i=0;i<n;i++) {
+      if (lambda[i] > tObj->MinMagThresh) {
+         /* minification */
+         switch (tObj->MinFilter) {
+            case GL_NEAREST:
+               sample_2d_nearest( tObj, tObj->Image[tObj->BaseLevel], s[i], t[i], rgba[i] );
+               break;
+            case GL_LINEAR:
+               sample_2d_linear( tObj, tObj->Image[tObj->BaseLevel], s[i], t[i], rgba[i] );
+               break;
+            case GL_NEAREST_MIPMAP_NEAREST:
+               sample_2d_nearest_mipmap_nearest( tObj, s[i], t[i], lambda[i], rgba[i] );
+               break;
+            case GL_LINEAR_MIPMAP_NEAREST:
+               sample_2d_linear_mipmap_nearest( tObj, s[i], t[i], lambda[i], rgba[i] );
+               break;
+            case GL_NEAREST_MIPMAP_LINEAR:
+               sample_2d_nearest_mipmap_linear( tObj, s[i], t[i], lambda[i], rgba[i] );
+               break;
+            case GL_LINEAR_MIPMAP_LINEAR:
+               sample_2d_linear_mipmap_linear( tObj, s[i], t[i], lambda[i], rgba[i] );
+               break;
+            default:
+               gl_problem(NULL, "Bad min filter in sample_2d_texture");
+               return;
+         }
+      }
+      else {
+         /* magnification */
+         switch (tObj->MagFilter) {
+            case GL_NEAREST:
+               sample_2d_nearest( tObj, tObj->Image[tObj->BaseLevel], s[i], t[i], rgba[i] );
+               break;
+            case GL_LINEAR:
+               sample_2d_linear( tObj, tObj->Image[tObj->BaseLevel], s[i], t[i], rgba[i] );
+               break;
+            default:
+               gl_problem(NULL, "Bad mag filter in sample_2d_texture");
+         }
+      }
+   }
+}
+
+
+/*
+ * Optimized 2-D texture sampling:
+ *    S and T wrap mode == GL_REPEAT
+ *    GL_NEAREST min/mag filter
+ *    No border
+ *    Format = GL_RGB
+ */
+static void opt_sample_rgb_2d( const struct gl_texture_object *tObj,
+                               GLuint n, const GLfloat s[], const GLfloat t[],
+                               const GLfloat u[], const GLfloat lambda[],
+                               GLchan rgba[][4] )
+{
+   const struct gl_texture_image *img = tObj->Image[tObj->BaseLevel];
+   const GLfloat width = (GLfloat) img->Width;
+   const GLfloat height = (GLfloat) img->Height;
+   const GLint colMask = img->Width - 1;
+   const GLint rowMask = img->Height - 1;
+   const GLint shift = img->WidthLog2;
+   GLuint k;
+   (void) u;
+   (void) lambda;
+   ASSERT(tObj->WrapS==GL_REPEAT);
+   ASSERT(tObj->WrapT==GL_REPEAT);
+   ASSERT(tObj->MinFilter==GL_NEAREST);
+   ASSERT(tObj->MagFilter==GL_NEAREST);
+   ASSERT(img->Border==0);
+   ASSERT(img->Format==GL_RGB);
+
+   /* NOTE: negative float->int doesn't floor, add 10000 as to work-around */
+   for (k=0;k<n;k++) {
+      GLint i = (GLint) ((s[k] + 10000.0) * width) & colMask;
+      GLint j = (GLint) ((t[k] + 10000.0) * height) & rowMask;
+      GLint pos = (j << shift) | i;
+      GLchan *texel = img->Data + pos + pos + pos;  /* pos*3 */
+      rgba[k][RCOMP] = texel[0];
+      rgba[k][GCOMP] = texel[1];
+      rgba[k][BCOMP] = texel[2];
+   }
+}
+
+
+/*
+ * Optimized 2-D texture sampling:
+ *    S and T wrap mode == GL_REPEAT
+ *    GL_NEAREST min/mag filter
+ *    No border
+ *    Format = GL_RGBA
+ */
+static void opt_sample_rgba_2d( const struct gl_texture_object *tObj,
+                                GLuint n, const GLfloat s[], const GLfloat t[],
+                                const GLfloat u[], const GLfloat lambda[],
+                                GLchan rgba[][4] )
+{
+   const struct gl_texture_image *img = tObj->Image[tObj->BaseLevel];
+   const GLfloat width = (GLfloat) img->Width;
+   const GLfloat height = (GLfloat) img->Height;
+   const GLint colMask = img->Width - 1;
+   const GLint rowMask = img->Height - 1;
+   const GLint shift = img->WidthLog2;
+   GLuint k;
+   (void) u;
+   (void) lambda;
+   ASSERT(tObj->WrapS==GL_REPEAT);
+   ASSERT(tObj->WrapT==GL_REPEAT);
+   ASSERT(tObj->MinFilter==GL_NEAREST);
+   ASSERT(tObj->MagFilter==GL_NEAREST);
+   ASSERT(img->Border==0);
+   ASSERT(img->Format==GL_RGBA);
+
+   /* NOTE: negative float->int doesn't floor, add 10000 as to work-around */
+   for (k=0;k<n;k++) {
+      GLint i = (GLint) ((s[k] + 10000.0) * width) & colMask;
+      GLint j = (GLint) ((t[k] + 10000.0) * height) & rowMask;
+      GLint pos = (j << shift) | i;
+      GLchan *texel = img->Data + (pos << 2);    /* pos*4 */
+      rgba[k][RCOMP] = texel[0];
+      rgba[k][GCOMP] = texel[1];
+      rgba[k][BCOMP] = texel[2];
+      rgba[k][ACOMP] = texel[3];
+   }
+}
+
+
+
+/**********************************************************************/
+/*                    3-D Texture Sampling Functions                  */
+/**********************************************************************/
+
+/*
+ * Given a texture image and an (i,j,k) integer texel coordinate, return the
+ * texel color.
+ */
+static void get_3d_texel( const struct gl_texture_object *tObj,
+                          const struct gl_texture_image *img,
+                          GLint i, GLint j, GLint k,
+                          GLchan rgba[4] )
+{
+   const GLint width = img->Width;    /* includes border */
+   const GLint height = img->Height;  /* includes border */
+   const GLint rectarea = width * height;
+   const GLchan *texel;
+
+#ifdef DEBUG
+   const GLint depth = img->Depth;    /* includes border */
+   assert(i >= 0);
+   assert(i < width);
+   assert(j >= 0);
+   assert(j < height);
+   assert(k >= 0);
+   assert(k < depth);
+#endif
+
+   switch (img->Format) {
+      case GL_COLOR_INDEX:
+         {
+            GLint index = img->Data[ rectarea * k +  width * j + i ];
+            palette_sample(tObj, index, rgba );
+            return;
+         }
+      case GL_ALPHA:
+         rgba[ACOMP] = img->Data[ rectarea * k +  width * j + i ];
+         return;
+      case GL_LUMINANCE:
+      case GL_INTENSITY:
+         rgba[RCOMP] = img->Data[ rectarea * k +  width * j + i ];
+         return;
+      case GL_LUMINANCE_ALPHA:
+         texel = img->Data + ( rectarea * k + width * j + i) * 2;
+         rgba[RCOMP] = texel[0];
+         rgba[ACOMP] = texel[1];
+         return;
+      case GL_RGB:
+         texel = img->Data + (rectarea * k + width * j + i) * 3;
+         rgba[RCOMP] = texel[0];
+         rgba[GCOMP] = texel[1];
+         rgba[BCOMP] = texel[2];
+         return;
+      case GL_RGBA:
+         texel = img->Data + (rectarea * k + width * j + i) * 4;
+         rgba[RCOMP] = texel[0];
+         rgba[GCOMP] = texel[1];
+         rgba[BCOMP] = texel[2];
+         rgba[ACOMP] = texel[3];
+         return;
+      default:
+         gl_problem(NULL, "Bad format in get_3d_texel");
+   }
+}
+
+
+/*
+ * Return the texture sample for coordinate (s,t,r) using GL_NEAREST filter.
+ */
+static void sample_3d_nearest( const struct gl_texture_object *tObj,
+                               const struct gl_texture_image *img,
+                               GLfloat s, GLfloat t, GLfloat r,
+                               GLchan rgba[4] )
+{
+   const GLint imgWidth = img->Width;   /* includes border, if any */
+   const GLint imgHeight = img->Height; /* includes border, if any */
+   const GLint width = img->Width2;     /* without border, power of two */
+   const GLint height = img->Height2;   /* without border, power of two */
+   const GLint depth = img->Depth2;     /* without border, power of two */
+   const GLint rectarea = imgWidth * imgHeight;
+   const GLchan *texel;
+   GLint i, j, k;
+
+   COMPUTE_NEAREST_TEXEL_LOCATION(tObj->WrapS, s, width,  i);
+   COMPUTE_NEAREST_TEXEL_LOCATION(tObj->WrapT, t, height, j);
+   COMPUTE_NEAREST_TEXEL_LOCATION(tObj->WrapR, r, depth,  k);
+
+   switch (tObj->Image[0]->Format) {
+      case GL_COLOR_INDEX:
+         {
+            GLint index = img->Data[ rectarea * k + j * imgWidth + i ];
+            palette_sample(tObj, index, rgba );
+            return;
+         }
+      case GL_ALPHA:
+         rgba[ACOMP] = img->Data[ rectarea * k + j * imgWidth + i ];
+         return;
+      case GL_LUMINANCE:
+      case GL_INTENSITY:
+         rgba[RCOMP] = img->Data[ rectarea * k + j * imgWidth + i ];
+         return;
+      case GL_LUMINANCE_ALPHA:
+         texel = img->Data + ((rectarea * k + j * imgWidth + i) << 1);
+         rgba[RCOMP] = texel[0];
+         rgba[ACOMP] = texel[1];
+         return;
+      case GL_RGB:
+         texel = img->Data + ( rectarea * k + j * imgWidth + i) * 3;
+         rgba[RCOMP] = texel[0];
+         rgba[GCOMP] = texel[1];
+         rgba[BCOMP] = texel[2];
+         return;
+      case GL_RGBA:
+         texel = img->Data + ((rectarea * k + j * imgWidth + i) << 2);
+         rgba[RCOMP] = texel[0];
+         rgba[GCOMP] = texel[1];
+         rgba[BCOMP] = texel[2];
+         rgba[ACOMP] = texel[3];
+         return;
+      default:
+         gl_problem(NULL, "Bad format in sample_3d_nearest");
+   }
+}
+
+
+
+/*
+ * Return the texture sample for coordinate (s,t,r) using GL_LINEAR filter.
+ */
+static void sample_3d_linear( const struct gl_texture_object *tObj,
+                              const struct gl_texture_image *img,
+                              GLfloat s, GLfloat t, GLfloat r,
+                              GLchan rgba[4] )
+{
+   const GLint width = img->Width2;
+   const GLint height = img->Height2;
+   const GLint depth = img->Depth2;
+   GLint i0, j0, k0, i1, j1, k1;
+   GLuint useBorderColor;
+   GLfloat u, v, w;
+
+   COMPUTE_LINEAR_TEXEL_LOCATIONS(tObj->WrapS, s, u, width,  i0, i1);
+   COMPUTE_LINEAR_TEXEL_LOCATIONS(tObj->WrapT, t, v, height, j0, j1);
+   COMPUTE_LINEAR_TEXEL_LOCATIONS(tObj->WrapR, r, w, depth,  k0, k1);
+
+   useBorderColor = 0;
+   if (img->Border) {
+      i0 += img->Border;
+      i1 += img->Border;
+      j0 += img->Border;
+      j1 += img->Border;
+      k0 += img->Border;
+      k1 += img->Border;
+   }
+   else {
+      /* check if sampling texture border color */
+      if (i0 < 0 || i0 >= width)   useBorderColor |= I0BIT;
+      if (i1 < 0 || i1 >= width)   useBorderColor |= I1BIT;
+      if (j0 < 0 || j0 >= height)  useBorderColor |= J0BIT;
+      if (j1 < 0 || j1 >= height)  useBorderColor |= J1BIT;
+      if (k0 < 0 || k0 >= depth)   useBorderColor |= K0BIT;
+      if (k1 < 0 || k1 >= depth)   useBorderColor |= K1BIT;
+   }
+
+   {
+      const GLfloat a = myFrac(u);
+      const GLfloat b = myFrac(v);
+      const GLfloat c = myFrac(w);
+      /* compute sample weights in fixed point in [0,WEIGHT_SCALE] */
+      GLint w000 = (GLint) ((1.0F-a)*(1.0F-b)*(1.0F-c) * WEIGHT_SCALE + 0.5F);
+      GLint w100 = (GLint) (      a *(1.0F-b)*(1.0F-c) * WEIGHT_SCALE + 0.5F);
+      GLint w010 = (GLint) ((1.0F-a)*      b *(1.0F-c) * WEIGHT_SCALE + 0.5F);
+      GLint w110 = (GLint) (      a *      b *(1.0F-c) * WEIGHT_SCALE + 0.5F);
+      GLint w001 = (GLint) ((1.0F-a)*(1.0F-b)*      c  * WEIGHT_SCALE + 0.5F);
+      GLint w101 = (GLint) (      a *(1.0F-b)*      c  * WEIGHT_SCALE + 0.5F);
+      GLint w011 = (GLint) ((1.0F-a)*      b *      c  * WEIGHT_SCALE + 0.5F);
+      GLint w111 = (GLint) (      a *      b *      c  * WEIGHT_SCALE + 0.5F);
+
+      GLchan t000[4], t010[4], t001[4], t011[4];
+      GLchan t100[4], t110[4], t101[4], t111[4];
+
+      if (useBorderColor & (I0BIT | J0BIT | K0BIT)) {
+         COPY_CHAN4(t000, tObj->BorderColor);
+      }
+      else {
+         get_3d_texel( tObj, img, i0, j0, k0, t000 );
+      }
+      if (useBorderColor & (I1BIT | J0BIT | K0BIT)) {
+         COPY_CHAN4(t100, tObj->BorderColor);
+      }
+      else {
+         get_3d_texel( tObj, img, i1, j0, k0, t100 );
+      }
+      if (useBorderColor & (I0BIT | J1BIT | K0BIT)) {
+         COPY_CHAN4(t010, tObj->BorderColor);
+      }
+      else {
+         get_3d_texel( tObj, img, i0, j1, k0, t010 );
+      }
+      if (useBorderColor & (I1BIT | J1BIT | K0BIT)) {
+         COPY_CHAN4(t110, tObj->BorderColor);
+      }
+      else {
+         get_3d_texel( tObj, img, i1, j1, k0, t110 );
+      }
+
+      if (useBorderColor & (I0BIT | J0BIT | K1BIT)) {
+         COPY_CHAN4(t001, tObj->BorderColor);
+      }
+      else {
+         get_3d_texel( tObj, img, i0, j0, k1, t001 );
+      }
+      if (useBorderColor & (I1BIT | J0BIT | K1BIT)) {
+         COPY_CHAN4(t101, tObj->BorderColor);
+      }
+      else {
+         get_3d_texel( tObj, img, i1, j0, k1, t101 );
+      }
+      if (useBorderColor & (I0BIT | J1BIT | K1BIT)) {
+         COPY_CHAN4(t011, tObj->BorderColor);
+      }
+      else {
+         get_3d_texel( tObj, img, i0, j1, k1, t011 );
+      }
+      if (useBorderColor & (I1BIT | J1BIT | K1BIT)) {
+         COPY_CHAN4(t111, tObj->BorderColor);
+      }
+      else {
+         get_3d_texel( tObj, img, i1, j1, k1, t111 );
+      }
+
+      rgba[0] = (GLchan) (
+                 (w000*t000[0] + w010*t010[0] + w001*t001[0] + w011*t011[0] +
+                  w100*t100[0] + w110*t110[0] + w101*t101[0] + w111*t111[0]  )
+                 >> WEIGHT_SHIFT);
+      rgba[1] = (GLchan) (
+                 (w000*t000[1] + w010*t010[1] + w001*t001[1] + w011*t011[1] +
+                  w100*t100[1] + w110*t110[1] + w101*t101[1] + w111*t111[1] )
+                 >> WEIGHT_SHIFT);
+      rgba[2] = (GLchan) (
+                 (w000*t000[2] + w010*t010[2] + w001*t001[2] + w011*t011[2] +
+                  w100*t100[2] + w110*t110[2] + w101*t101[2] + w111*t111[2] )
+                 >> WEIGHT_SHIFT);
+      rgba[3] = (GLchan) (
+                 (w000*t000[3] + w010*t010[3] + w001*t001[3] + w011*t011[3] +
+                  w100*t100[3] + w110*t110[3] + w101*t101[3] + w111*t111[3] )
+                 >> WEIGHT_SHIFT);
+   }
+}
+
+
+
+static void
+sample_3d_nearest_mipmap_nearest( const struct gl_texture_object *tObj,
+                                  GLfloat s, GLfloat t, GLfloat r,
+                                  GLfloat lambda, GLchan rgba[4] )
+{
+   GLint level;
+   COMPUTE_NEAREST_MIPMAP_LEVEL(tObj, lambda, level);
+   sample_3d_nearest( tObj, tObj->Image[level], s, t, r, rgba );
+}
+
+
+static void
+sample_3d_linear_mipmap_nearest( const struct gl_texture_object *tObj,
+                                 GLfloat s, GLfloat t, GLfloat r,
+                                 GLfloat lambda, GLchan rgba[4] )
+{
+   GLint level;
+   COMPUTE_NEAREST_MIPMAP_LEVEL(tObj, lambda, level);
+   sample_3d_linear( tObj, tObj->Image[level], s, t, r, rgba );
+}
+
+
+static void
+sample_3d_nearest_mipmap_linear( const struct gl_texture_object *tObj,
+                                 GLfloat s, GLfloat t, GLfloat r,
+                                 GLfloat lambda, GLchan rgba[4] )
+{
+   GLint level;
+
+   COMPUTE_LINEAR_MIPMAP_LEVEL(tObj, lambda, level);
+
+   if (level >= tObj->P) {
+      sample_3d_nearest( tObj, tObj->Image[tObj->P], s, t, r, rgba );
+   }
+   else {
+      GLchan t0[4], t1[4];  /* texels */
+      const GLfloat f = myFrac(lambda);
+      sample_3d_nearest( tObj, tObj->Image[level  ], s, t, r, t0 );
+      sample_3d_nearest( tObj, tObj->Image[level+1], s, t, r, t1 );
+      rgba[RCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[RCOMP] + f * t1[RCOMP]);
+      rgba[GCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[GCOMP] + f * t1[GCOMP]);
+      rgba[BCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[BCOMP] + f * t1[BCOMP]);
+      rgba[ACOMP] = (GLchan) (GLint) ((1.0F-f) * t0[ACOMP] + f * t1[ACOMP]);
+   }
+}
+
+
+static void
+sample_3d_linear_mipmap_linear( const struct gl_texture_object *tObj,
+                                GLfloat s, GLfloat t, GLfloat r,
+                                GLfloat lambda, GLchan rgba[4] )
+{
+   GLint level;
+
+   COMPUTE_LINEAR_MIPMAP_LEVEL(tObj, lambda, level);
+
+   if (level >= tObj->P) {
+      sample_3d_linear( tObj, tObj->Image[tObj->P], s, t, r, rgba );
+   }
+   else {
+      GLchan t0[4], t1[4];  /* texels */
+      const GLfloat f = myFrac(lambda);
+      sample_3d_linear( tObj, tObj->Image[level  ], s, t, r, t0 );
+      sample_3d_linear( tObj, tObj->Image[level+1], s, t, r, t1 );
+      rgba[RCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[RCOMP] + f * t1[RCOMP]);
+      rgba[GCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[GCOMP] + f * t1[GCOMP]);
+      rgba[BCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[BCOMP] + f * t1[BCOMP]);
+      rgba[ACOMP] = (GLchan) (GLint) ((1.0F-f) * t0[ACOMP] + f * t1[ACOMP]);
+   }
+}
+
+
+static void sample_nearest_3d( const struct gl_texture_object *tObj, GLuint n,
+                               const GLfloat s[], const GLfloat t[],
+                               const GLfloat u[], const GLfloat lambda[],
+                               GLchan rgba[][4] )
+{
+   GLuint i;
+   struct gl_texture_image *image = tObj->Image[tObj->BaseLevel];
+   (void) lambda;
+   for (i=0;i<n;i++) {
+      sample_3d_nearest( tObj, image, s[i], t[i], u[i], rgba[i] );
+   }
+}
+
+
+
+static void sample_linear_3d( const struct gl_texture_object *tObj, GLuint n,
+                              const GLfloat s[], const GLfloat t[],
+                              const GLfloat u[], const GLfloat lambda[],
+                              GLchan rgba[][4] )
+{
+   GLuint i;
+   struct gl_texture_image *image = tObj->Image[tObj->BaseLevel];
+   (void) lambda;
+   for (i=0;i<n;i++) {
+      sample_3d_linear( tObj, image, s[i], t[i], u[i], rgba[i] );
+   }
+}
+
+
+/*
+ * Given an (s,t,r) texture coordinate and lambda (level of detail) value,
+ * return a texture sample.
+ */
+static void sample_lambda_3d( const struct gl_texture_object *tObj, GLuint n,
+                              const GLfloat s[], const GLfloat t[],
+                              const GLfloat u[], const GLfloat lambda[],
+                              GLchan rgba[][4] )
+{
+   GLuint i;
+
+   for (i=0;i<n;i++) {
+
+      if (lambda[i] > tObj->MinMagThresh) {
+         /* minification */
+         switch (tObj->MinFilter) {
+            case GL_NEAREST:
+               sample_3d_nearest( tObj, tObj->Image[tObj->BaseLevel], s[i], t[i], u[i], rgba[i] );
+               break;
+            case GL_LINEAR:
+               sample_3d_linear( tObj, tObj->Image[tObj->BaseLevel], s[i], t[i], u[i], rgba[i] );
+               break;
+            case GL_NEAREST_MIPMAP_NEAREST:
+               sample_3d_nearest_mipmap_nearest( tObj, s[i], t[i], u[i], lambda[i], rgba[i] );
+               break;
+            case GL_LINEAR_MIPMAP_NEAREST:
+               sample_3d_linear_mipmap_nearest( tObj, s[i], t[i], u[i], lambda[i], rgba[i] );
+               break;
+            case GL_NEAREST_MIPMAP_LINEAR:
+               sample_3d_nearest_mipmap_linear( tObj, s[i], t[i], u[i], lambda[i], rgba[i] );
+               break;
+            case GL_LINEAR_MIPMAP_LINEAR:
+               sample_3d_linear_mipmap_linear( tObj, s[i], t[i], u[i], lambda[i], rgba[i] );
+               break;
+            default:
+               gl_problem(NULL, "Bad min filterin sample_3d_texture");
+         }
+      }
+      else {
+         /* magnification */
+         switch (tObj->MagFilter) {
+            case GL_NEAREST:
+               sample_3d_nearest( tObj, tObj->Image[tObj->BaseLevel], s[i], t[i], u[i], rgba[i] );
+               break;
+            case GL_LINEAR:
+               sample_3d_linear( tObj, tObj->Image[tObj->BaseLevel], s[i], t[i], u[i], rgba[i] );
+               break;
+            default:
+               gl_problem(NULL, "Bad mag filter in sample_3d_texture");
+         }
+      }
+   }
+}
+
+
+/**********************************************************************/
+/*                Texture Cube Map Sampling Functions                 */
+/**********************************************************************/
+
+/*
+ * Choose one of six sides of a texture cube map given the texture
+ * coord (rx,ry,rz).  Return pointer to corresponding array of texture
+ * images.
+ */
+static const struct gl_texture_image **
+choose_cube_face(const struct gl_texture_object *texObj,
+                 GLfloat rx, GLfloat ry, GLfloat rz,
+                 GLfloat *newS, GLfloat *newT)
+{
+/*
+      major axis
+      direction     target                             sc     tc    ma
+      ----------    -------------------------------    ---    ---   ---
+       +rx          TEXTURE_CUBE_MAP_POSITIVE_X_EXT    -rz    -ry   rx
+       -rx          TEXTURE_CUBE_MAP_NEGATIVE_X_EXT    +rz    -ry   rx
+       +ry          TEXTURE_CUBE_MAP_POSITIVE_Y_EXT    +rx    +rz   ry
+       -ry          TEXTURE_CUBE_MAP_NEGATIVE_Y_EXT    +rx    -rz   ry
+       +rz          TEXTURE_CUBE_MAP_POSITIVE_Z_EXT    +rx    -ry   rz
+       -rz          TEXTURE_CUBE_MAP_NEGATIVE_Z_EXT    -rx    -ry   rz
+*/
+   const struct gl_texture_image **imgArray;
+   const GLfloat arx = ABSF(rx),   ary = ABSF(ry),   arz = ABSF(rz);
+   GLfloat sc, tc, ma;
+
+   if (arx > ary && arx > arz) {
+      if (rx >= 0.0F) {
+         imgArray = (const struct gl_texture_image **) texObj->Image;
+         sc = -rz;
+         tc = -ry;
+         ma = arx;
+      }
+      else {
+         imgArray = (const struct gl_texture_image **) texObj->NegX;
+         sc = rz;
+         tc = -ry;
+         ma = arx;
+      }
+   }
+   else if (ary > arx && ary > arz) {
+      if (ry >= 0.0F) {
+         imgArray = (const struct gl_texture_image **) texObj->PosY;
+         sc = rx;
+         tc = rz;
+         ma = ary;
+      }
+      else {
+         imgArray = (const struct gl_texture_image **) texObj->NegY;
+         sc = rx;
+         tc = -rz;
+         ma = ary;
+      }
+   }
+   else {
+      if (rz > 0.0F) {
+         imgArray = (const struct gl_texture_image **) texObj->PosZ;
+         sc = rx;
+         tc = -ry;
+         ma = arz;
+      }
+      else {
+         imgArray = (const struct gl_texture_image **) texObj->NegZ;
+         sc = -rx;
+         tc = -ry;
+         ma = arz;
+      }
+   }
+
+   *newS = ( sc / ma + 1.0F ) * 0.5F;
+   *newT = ( tc / ma + 1.0F ) * 0.5F;
+   return imgArray;
+}
+
+
+static void
+sample_nearest_cube(const struct gl_texture_object *tObj, GLuint n,
+                    const GLfloat s[], const GLfloat t[],
+                    const GLfloat u[], const GLfloat lambda[],
+                    GLchan rgba[][4])
+{
+   GLuint i;
+   (void) lambda;
+   for (i = 0; i < n; i++) {
+      const struct gl_texture_image **images;
+      GLfloat newS, newT;
+      images = choose_cube_face(tObj, s[i], t[i], u[i], &newS, &newT);
+      sample_2d_nearest( tObj, images[tObj->BaseLevel], newS, newT, rgba[i] );
+   }
+}
+
+
+static void
+sample_linear_cube(const struct gl_texture_object *tObj, GLuint n,
+                   const GLfloat s[], const GLfloat t[],
+                   const GLfloat u[], const GLfloat lambda[],
+                   GLchan rgba[][4])
+{
+   GLuint i;
+   (void) lambda;
+   for (i = 0; i < n; i++) {
+      const struct gl_texture_image **images;
+      GLfloat newS, newT;
+      images = choose_cube_face(tObj, s[i], t[i], u[i], &newS, &newT);
+      sample_2d_linear( tObj, images[tObj->BaseLevel], newS, newT, rgba[i] );
+   }
+}
+
+
+static void
+sample_cube_nearest_mipmap_nearest( const struct gl_texture_object *tObj,
+                                    GLfloat s, GLfloat t, GLfloat u,
+                                    GLfloat lambda, GLchan rgba[4] )
+{
+   const struct gl_texture_image **images;
+   GLfloat newS, newT;
+   GLint level;
+
+   COMPUTE_NEAREST_MIPMAP_LEVEL(tObj, lambda, level);
+
+   images = choose_cube_face(tObj, s, t, u, &newS, &newT);
+   sample_2d_nearest( tObj, images[level], newS, newT, rgba );
+}
+
+
+static void
+sample_cube_linear_mipmap_nearest( const struct gl_texture_object *tObj,
+                                   GLfloat s, GLfloat t, GLfloat u,
+                                   GLfloat lambda, GLchan rgba[4] )
+{
+   const struct gl_texture_image **images;
+   GLfloat newS, newT;
+   GLint level;
+
+   COMPUTE_NEAREST_MIPMAP_LEVEL(tObj, lambda, level);
+
+   images = choose_cube_face(tObj, s, t, u, &newS, &newT);
+   sample_2d_linear( tObj, images[level], newS, newT, rgba );
+}
+
+
+static void
+sample_cube_nearest_mipmap_linear( const struct gl_texture_object *tObj,
+                                   GLfloat s, GLfloat t, GLfloat u,
+                                   GLfloat lambda, GLchan rgba[4] )
+{
+   const struct gl_texture_image **images;
+   GLfloat newS, newT;
+   GLint level;
+
+   COMPUTE_LINEAR_MIPMAP_LEVEL(tObj, lambda, level);
+
+   images = choose_cube_face(tObj, s, t, u, &newS, &newT);
+
+   if (level >= tObj->P) {
+      sample_2d_nearest( tObj, images[tObj->P], newS, newT, rgba );
+   }
+   else {
+      GLchan t0[4], t1[4];  /* texels */
+      const GLfloat f = myFrac(lambda);
+      sample_2d_nearest( tObj, images[level  ], newS, newT, t0 );
+      sample_2d_nearest( tObj, images[level+1], newS, newT, t1 );
+      rgba[RCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[RCOMP] + f * t1[RCOMP]);
+      rgba[GCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[GCOMP] + f * t1[GCOMP]);
+      rgba[BCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[BCOMP] + f * t1[BCOMP]);
+      rgba[ACOMP] = (GLchan) (GLint) ((1.0F-f) * t0[ACOMP] + f * t1[ACOMP]);
+   }
+}
+
+
+static void
+sample_cube_linear_mipmap_linear( const struct gl_texture_object *tObj,
+                                  GLfloat s, GLfloat t, GLfloat u,
+                                  GLfloat lambda, GLchan rgba[4] )
+{
+   const struct gl_texture_image **images;
+   GLfloat newS, newT;
+   GLint level;
+
+   COMPUTE_LINEAR_MIPMAP_LEVEL(tObj, lambda, level);
+
+   images = choose_cube_face(tObj, s, t, u, &newS, &newT);
+
+   if (level >= tObj->P) {
+      sample_2d_linear( tObj, images[tObj->P], newS, newT, rgba );
+   }
+   else {
+      GLchan t0[4], t1[4];
+      const GLfloat f = myFrac(lambda);
+      sample_2d_linear( tObj, images[level  ], newS, newT, t0 );
+      sample_2d_linear( tObj, images[level+1], newS, newT, t1 );
+      rgba[RCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[RCOMP] + f * t1[RCOMP]);
+      rgba[GCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[GCOMP] + f * t1[GCOMP]);
+      rgba[BCOMP] = (GLchan) (GLint) ((1.0F-f) * t0[BCOMP] + f * t1[BCOMP]);
+      rgba[ACOMP] = (GLchan) (GLint) ((1.0F-f) * t0[ACOMP] + f * t1[ACOMP]);
+   }
+}
+
+
+static void
+sample_lambda_cube(const struct gl_texture_object *tObj, GLuint n,
+                   const GLfloat s[], const GLfloat t[],
+                   const GLfloat u[], const GLfloat lambda[],
+                   GLchan rgba[][4])
+{
+   GLuint i;
+
+   for (i = 0; i < n; i++) {
+      if (lambda[i] > tObj->MinMagThresh) {
+         /* minification */
+         switch (tObj->MinFilter) {
+            case GL_NEAREST:
+               {
+                  const struct gl_texture_image **images;
+                  GLfloat newS, newT;
+                  images = choose_cube_face(tObj, s[i], t[i], u[i],
+                                            &newS, &newT);
+                  sample_2d_nearest( tObj, images[tObj->BaseLevel],
+                                     newS, newT, rgba[i] );
+               }
+               break;
+            case GL_LINEAR:
+               {
+                  const struct gl_texture_image **images;
+                  GLfloat newS, newT;
+                  images = choose_cube_face(tObj, s[i], t[i], u[i],
+                                            &newS, &newT);
+                  sample_2d_linear( tObj, images[tObj->BaseLevel],
+                                    newS, newT, rgba[i] );
+               }
+               break;
+            case GL_NEAREST_MIPMAP_NEAREST:
+               sample_cube_nearest_mipmap_nearest( tObj, s[i], t[i], u[i],
+                                                   lambda[i], rgba[i] );
+               break;
+            case GL_LINEAR_MIPMAP_NEAREST:
+               sample_cube_linear_mipmap_nearest( tObj, s[i], t[i], u[i],
+                                                  lambda[i], rgba[i] );
+               break;
+            case GL_NEAREST_MIPMAP_LINEAR:
+               sample_cube_nearest_mipmap_linear( tObj, s[i], t[i], u[i],
+                                                  lambda[i], rgba[i] );
+               break;
+            case GL_LINEAR_MIPMAP_LINEAR:
+               sample_cube_linear_mipmap_linear( tObj, s[i], t[i], u[i],
+                                                 lambda[i], rgba[i] );
+               break;
+            default:
+               gl_problem(NULL, "Bad min filter in sample_lambda_cube");
+         }
+      }
+      else {
+         /* magnification */
+         const struct gl_texture_image **images;
+         GLfloat newS, newT;
+         images = choose_cube_face(tObj, s[i], t[i], u[i],
+                                   &newS, &newT);
+         switch (tObj->MagFilter) {
+            case GL_NEAREST:
+               sample_2d_nearest( tObj, images[tObj->BaseLevel],
+                                  newS, newT, rgba[i] );
+               break;
+            case GL_LINEAR:
+               sample_2d_linear( tObj, images[tObj->BaseLevel],
+                                 newS, newT, rgba[i] );
+               break;
+            default:
+               gl_problem(NULL, "Bad mag filter in sample_lambda_cube");
+         }
+      }
+   }
+}
+
+
+/**********************************************************************/
+/*                       Texture Sampling Setup                       */
+/**********************************************************************/
+
+
+/*
+ * Setup the texture sampling function for this texture object.
+ */
+void
+_swrast_set_texture_sampler( struct gl_texture_object *t )
+{
+   if (!t->Complete) {
+      t->SampleFunc = NULL;
+   }
+   else {
+      GLboolean needLambda = (GLboolean) (t->MinFilter != t->MagFilter);
+
+      if (needLambda) {
+         /* Compute min/mag filter threshold */
+         if (t->MagFilter==GL_LINEAR
+             && (t->MinFilter==GL_NEAREST_MIPMAP_NEAREST ||
+                 t->MinFilter==GL_LINEAR_MIPMAP_NEAREST)) {
+            t->MinMagThresh = 0.5F;
+         }
+         else {
+            t->MinMagThresh = 0.0F;
+         }
+      }
+
+      switch (t->Dimensions) {
+         case 1:
+            if (needLambda) {
+               t->SampleFunc = sample_lambda_1d;
+            }
+            else if (t->MinFilter==GL_LINEAR) {
+               t->SampleFunc = sample_linear_1d;
+            }
+            else {
+               ASSERT(t->MinFilter==GL_NEAREST);
+               t->SampleFunc = sample_nearest_1d;
+            }
+            break;
+         case 2:
+            if (needLambda) {
+               t->SampleFunc = sample_lambda_2d;
+            }
+            else if (t->MinFilter==GL_LINEAR) {
+               t->SampleFunc = sample_linear_2d;
+            }
+            else {
+               ASSERT(t->MinFilter==GL_NEAREST);
+               if (t->WrapS==GL_REPEAT && t->WrapT==GL_REPEAT
+                   && t->Image[0]->Border==0 && t->Image[0]->Format==GL_RGB) {
+                  t->SampleFunc = opt_sample_rgb_2d;
+               }
+               else if (t->WrapS==GL_REPEAT && t->WrapT==GL_REPEAT
+                   && t->Image[0]->Border==0 && t->Image[0]->Format==GL_RGBA) {
+                  t->SampleFunc = opt_sample_rgba_2d;
+               }
+               else
+                  t->SampleFunc = sample_nearest_2d;
+            }
+            break;
+         case 3:
+            if (needLambda) {
+               t->SampleFunc = sample_lambda_3d;
+            }
+            else if (t->MinFilter==GL_LINEAR) {
+               t->SampleFunc = sample_linear_3d;
+            }
+            else {
+               ASSERT(t->MinFilter==GL_NEAREST);
+               t->SampleFunc = sample_nearest_3d;
+            }
+            break;
+         case 6: /* cube map */
+            if (needLambda) {
+               t->SampleFunc = sample_lambda_cube;
+            }
+            else if (t->MinFilter==GL_LINEAR) {
+               t->SampleFunc = sample_linear_cube;
+            }
+            else {
+               ASSERT(t->MinFilter==GL_NEAREST);
+               t->SampleFunc = sample_nearest_cube;
+            }
+            break;
+         default:
+            gl_problem(NULL, "invalid dimensions in _mesa_set_texture_sampler");
+      }
+   }
+}
+
+
+#define PROD(A,B)   ( (GLuint)(A) * ((GLuint)(B)+1) )
+
+static INLINE void
+_mesa_texture_combine(const GLcontext *ctx,
+                      const struct gl_texture_unit *textureUnit,
+                      GLuint n,
+                      GLchan (*primary_rgba)[4],
+                      GLchan (*texel)[4],
+                      GLchan (*rgba)[4])
+{
+   GLchan ccolor [3][3*MAX_WIDTH][4];
+   GLchan (*argRGB [3])[4];
+   GLchan (*argA [3])[4];
+   GLuint i, j;
+   const GLuint RGBshift = textureUnit->CombineScaleShiftRGB;
+   const GLuint Ashift   = textureUnit->CombineScaleShiftA;
+
+   ASSERT(ctx->Extensions.EXT_texture_env_combine);
+
+   for (j = 0; j < 3; j++) {
+      switch (textureUnit->CombineSourceA[j]) {
+         case GL_TEXTURE:
+            argA[j] = texel;
+            break;
+         case GL_PRIMARY_COLOR_EXT:
+            argA[j] = primary_rgba;
+            break;
+         case GL_PREVIOUS_EXT:
+            argA[j] = rgba;
+            break;
+         case GL_CONSTANT_EXT:
+            {
+               GLchan (*c)[4] = ccolor[j];
+               GLchan alpha = FLOAT_TO_CHAN(textureUnit->EnvColor[3]);
+               for (i = 0; i < n; i++)
+                  c[i][ACOMP] = alpha;
+               argA[j] = ccolor[j];
+            }
+            break;
+         default:
+            gl_problem(NULL, "invalid combine source");
+      }
+
+      switch (textureUnit->CombineSourceRGB[j]) {
+         case GL_TEXTURE:
+            argRGB[j] = texel;
+            break;
+         case GL_PRIMARY_COLOR_EXT:
+            argRGB[j] = primary_rgba;
+            break;
+         case GL_PREVIOUS_EXT:
+            argRGB[j] = rgba;
+            break;
+         case GL_CONSTANT_EXT:
+            {
+               GLchan (*c)[4] = ccolor[j];
+               const GLchan red   = FLOAT_TO_CHAN(textureUnit->EnvColor[0]);
+               const GLchan green = FLOAT_TO_CHAN(textureUnit->EnvColor[1]);
+               const GLchan blue  = FLOAT_TO_CHAN(textureUnit->EnvColor[2]);
+               for (i = 0; i < n; i++) {
+                  c[i][RCOMP] = red;
+                  c[i][GCOMP] = green;
+                  c[i][BCOMP] = blue;
+               }
+               argRGB[j] = ccolor[j];
+            }
+            break;
+         default:
+            gl_problem(NULL, "invalid combine source");
+      }
+
+      if (textureUnit->CombineOperandRGB[j] != GL_SRC_COLOR) {
+         GLchan (*src)[4] = argRGB[j];
+         GLchan (*dst)[4] = ccolor[j];
+
+         argRGB[j] = ccolor[j];
+
+         if (textureUnit->CombineOperandRGB[j] == GL_ONE_MINUS_SRC_COLOR) {
+            for (i = 0; i < n; i++) {
+               dst[i][RCOMP] = CHAN_MAX - src[i][RCOMP];
+               dst[i][GCOMP] = CHAN_MAX - src[i][GCOMP];
+               dst[i][BCOMP] = CHAN_MAX - src[i][BCOMP];
+            }
+         }
+         else if (textureUnit->CombineOperandRGB[j] == GL_SRC_ALPHA) {
+            src = argA[j];
+            for (i = 0; i < n; i++) {
+               dst[i][RCOMP] = src[i][ACOMP];
+               dst[i][GCOMP] = src[i][ACOMP];
+               dst[i][BCOMP] = src[i][ACOMP];
+            }
+         }
+         else {                      /*  GL_ONE_MINUS_SRC_ALPHA  */
+            src = argA[j];
+            for (i = 0; i < n; i++) {
+               dst[i][RCOMP] = CHAN_MAX - src[i][ACOMP];
+               dst[i][GCOMP] = CHAN_MAX - src[i][ACOMP];
+               dst[i][BCOMP] = CHAN_MAX - src[i][ACOMP];
+            }
+         }
+      }
+
+      if (textureUnit->CombineOperandA[j] == GL_ONE_MINUS_SRC_ALPHA) {
+         GLchan (*src)[4] = argA[j];
+         GLchan (*dst)[4] = ccolor[j];
+         argA[j] = ccolor[j];
+         for (i = 0; i < n; i++) {
+            dst[i][ACOMP] = CHAN_MAX - src[i][ACOMP];
+         }
+      }
+
+      if (textureUnit->CombineModeRGB == GL_REPLACE &&
+          textureUnit->CombineModeA == GL_REPLACE) {
+         break;      /*  done, we need only arg0  */
+      }
+
+      if (j == 1 &&
+          textureUnit->CombineModeRGB != GL_INTERPOLATE_EXT &&
+          textureUnit->CombineModeA != GL_INTERPOLATE_EXT) {
+         break;      /*  arg0 and arg1 are done. we don't need arg2. */
+      }
+   }
+
+   switch (textureUnit->CombineModeRGB) {
+      case GL_REPLACE:
+         {
+            const GLchan (*arg0)[4] = (const GLchan (*)[4]) argRGB[0];
+            if (RGBshift) {
+               for (i = 0; i < n; i++) {
+                  GLuint r = (GLuint) arg0[i][RCOMP] << RGBshift;
+                  GLuint g = (GLuint) arg0[i][GCOMP] << RGBshift;
+                  GLuint b = (GLuint) arg0[i][BCOMP] << RGBshift;
+                  rgba[i][RCOMP] = MIN2(r, CHAN_MAX);
+                  rgba[i][GCOMP] = MIN2(g, CHAN_MAX);
+                  rgba[i][BCOMP] = MIN2(b, CHAN_MAX);
+               }
+            }
+            else {
+               for (i = 0; i < n; i++) {
+                  rgba[i][RCOMP] = arg0[i][RCOMP];
+                  rgba[i][GCOMP] = arg0[i][GCOMP];
+                  rgba[i][BCOMP] = arg0[i][BCOMP];
+               }
+            }
+         }
+         break;
+      case GL_MODULATE:
+         {
+            const GLchan (*arg0)[4] = (const GLchan (*)[4]) argRGB[0];
+            const GLchan (*arg1)[4] = (const GLchan (*)[4]) argRGB[1];
+            const GLint shift = 8 - RGBshift;
+            for (i = 0; i < n; i++) {
+               GLuint r = PROD(arg0[i][0], arg1[i][RCOMP]) >> shift;
+               GLuint g = PROD(arg0[i][1], arg1[i][GCOMP]) >> shift;
+               GLuint b = PROD(arg0[i][2], arg1[i][BCOMP]) >> shift;
+               rgba[i][RCOMP] = (GLchan) MIN2(r, CHAN_MAX);
+               rgba[i][GCOMP] = (GLchan) MIN2(g, CHAN_MAX);
+               rgba[i][BCOMP] = (GLchan) MIN2(b, CHAN_MAX);
+            }
+         }
+         break;
+      case GL_ADD:
+         {
+            const GLchan (*arg0)[4] = (const GLchan (*)[4]) argRGB[0];
+            const GLchan (*arg1)[4] = (const GLchan (*)[4]) argRGB[1];
+            for (i = 0; i < n; i++) {
+               GLint r = ((GLint) arg0[i][RCOMP] + (GLint) arg1[i][RCOMP]) << RGBshift;
+               GLint g = ((GLint) arg0[i][GCOMP] + (GLint) arg1[i][GCOMP]) << RGBshift;
+               GLint b = ((GLint) arg0[i][BCOMP] + (GLint) arg1[i][BCOMP]) << RGBshift;
+               rgba[i][RCOMP] = (GLchan) MIN2(r, CHAN_MAX);
+               rgba[i][GCOMP] = (GLchan) MIN2(g, CHAN_MAX);
+               rgba[i][BCOMP] = (GLchan) MIN2(b, CHAN_MAX);
+            }
+         }
+         break;
+      case GL_ADD_SIGNED_EXT:
+         {
+            const GLchan (*arg0)[4] = (const GLchan (*)[4]) argRGB[0];
+            const GLchan (*arg1)[4] = (const GLchan (*)[4]) argRGB[1];
+            for (i = 0; i < n; i++) {
+               GLint r = (GLint) arg0[i][RCOMP] + (GLint) arg1[i][RCOMP] - 128;
+               GLint g = (GLint) arg0[i][GCOMP] + (GLint) arg1[i][GCOMP] - 128;
+               GLint b = (GLint) arg0[i][BCOMP] + (GLint) arg1[i][BCOMP] - 128;
+               r = (r < 0) ? 0 : r << RGBshift;
+               g = (g < 0) ? 0 : g << RGBshift;
+               b = (b < 0) ? 0 : b << RGBshift;
+               rgba[i][RCOMP] = (GLchan) MIN2(r, CHAN_MAX);
+               rgba[i][GCOMP] = (GLchan) MIN2(g, CHAN_MAX);
+               rgba[i][BCOMP] = (GLchan) MIN2(b, CHAN_MAX);
+            }
+         }
+         break;
+      case GL_INTERPOLATE_EXT:
+         {
+            const GLchan (*arg0)[4] = (const GLchan (*)[4]) argRGB[0];
+            const GLchan (*arg1)[4] = (const GLchan (*)[4]) argRGB[1];
+            const GLchan (*arg2)[4] = (const GLchan (*)[4]) argRGB[2];
+            const GLint shift = 8 - RGBshift;
+            for (i = 0; i < n; i++) {
+               GLuint r = (PROD(arg0[i][RCOMP], arg2[i][RCOMP])
+                           + PROD(arg1[i][RCOMP], CHAN_MAX - arg2[i][RCOMP]))
+                              >> shift;
+               GLuint g = (PROD(arg0[i][GCOMP], arg2[i][GCOMP])
+                           + PROD(arg1[i][GCOMP], CHAN_MAX - arg2[i][GCOMP]))
+                              >> shift;
+               GLuint b = (PROD(arg0[i][BCOMP], arg2[i][BCOMP])
+                           + PROD(arg1[i][BCOMP], CHAN_MAX - arg2[i][BCOMP]))
+                              >> shift;
+               rgba[i][RCOMP] = (GLchan) MIN2(r, CHAN_MAX);
+               rgba[i][GCOMP] = (GLchan) MIN2(g, CHAN_MAX);
+               rgba[i][BCOMP] = (GLchan) MIN2(b, CHAN_MAX);
+            }
+         }
+         break;
+      default:
+         gl_problem(NULL, "invalid combine mode");
+   }
+
+   switch (textureUnit->CombineModeA) {
+      case GL_REPLACE:
+         {
+            const GLchan (*arg0)[4] = (const GLchan (*)[4]) argA[0];
+            if (Ashift) {
+               for (i = 0; i < n; i++) {
+                  GLuint a = (GLuint) arg0[i][ACOMP] << Ashift;
+                  rgba[i][ACOMP] = (GLchan) MIN2(a, CHAN_MAX);
+               }
+            }
+            else {
+               for (i = 0; i < n; i++) {
+                  rgba[i][ACOMP] = arg0[i][ACOMP];
+               }
+            }
+         }
+         break;
+      case GL_MODULATE:
+         {
+            const GLchan (*arg0)[4] = (const GLchan (*)[4]) argA[0];
+            const GLchan (*arg1)[4] = (const GLchan (*)[4]) argA[1];
+            const GLint shift = 8 - Ashift;
+            for (i = 0; i < n; i++) {
+               GLuint a = (PROD(arg0[i][ACOMP], arg1[i][ACOMP]) >> shift);
+               rgba[i][ACOMP] = (GLchan) MIN2(a, CHAN_MAX);
+            }
+         }
+         break;
+      case GL_ADD:
+         {
+            const GLchan (*arg0)[4] = (const GLchan (*)[4]) argA[0];
+            const GLchan  (*arg1)[4] = (const GLchan (*)[4]) argA[1];
+            for (i = 0; i < n; i++) {
+               GLint a = ((GLint) arg0[i][ACOMP] + arg1[i][ACOMP]) << Ashift;
+               rgba[i][ACOMP] = (GLchan) MIN2(a, CHAN_MAX);
+            }
+         }
+         break;
+      case GL_ADD_SIGNED_EXT:
+         {
+            const GLchan (*arg0)[4] = (const GLchan (*)[4]) argA[0];
+            const GLchan (*arg1)[4] = (const GLchan (*)[4]) argA[1];
+            for (i = 0; i < n; i++) {
+               GLint a = (GLint) arg0[i][ACOMP] + (GLint) arg1[i][ACOMP] - 128;
+               a = (a < 0) ? 0 : a << Ashift;
+               rgba[i][ACOMP] = (GLchan) MIN2(a, CHAN_MAX);
+            }
+         }
+         break;
+      case GL_INTERPOLATE_EXT:
+         {
+            const GLchan (*arg0)[4] = (const GLchan (*)[4]) argA[0];
+            const GLchan (*arg1)[4] = (const GLchan (*)[4]) argA[1];
+            const GLchan (*arg2)[4] = (const GLchan (*)[4]) argA[2];
+            const GLint shift = 8 - Ashift;
+            for (i=0; i<n; i++) {
+               GLuint a = (PROD(arg0[i][ACOMP], arg2[i][ACOMP])
+                           + PROD(arg1[i][ACOMP], CHAN_MAX - arg2[i][ACOMP]))
+                              >> shift;
+               rgba[i][ACOMP] = (GLchan) MIN2(a, CHAN_MAX);
+            }
+         }
+         break;
+      default:
+         gl_problem(NULL, "invalid combine mode");
+   }
+}
+#undef PROD
+
+
+
+/**********************************************************************/
+/*                      Texture Application                           */
+/**********************************************************************/
+
+
+/*
+ * Combine incoming fragment color with texel color to produce output color.
+ * Input:  textureUnit - pointer to texture unit to apply
+ *         format - base internal texture format
+ *         n - number of fragments
+ *         primary_rgba - primary colors (may be rgba for single texture)
+ *         texels - array of texel colors
+ * InOut:  rgba - incoming fragment colors modified by texel colors
+ *                according to the texture environment mode.
+ */
+static void
+apply_texture( const GLcontext *ctx,
+               const struct gl_texture_unit *texUnit,
+               GLuint n,
+               GLchan primary_rgba[][4], GLchan texel[][4],
+               GLchan rgba[][4] )
+{
+   GLint baseLevel;
+   GLuint i;
+   GLint Rc, Gc, Bc, Ac;
+   GLenum format;
+
+   ASSERT(texUnit);
+   ASSERT(texUnit->Current);
+
+   baseLevel = texUnit->Current->BaseLevel;
+   ASSERT(texUnit->Current->Image[baseLevel]);
+
+   format = texUnit->Current->Image[baseLevel]->Format;
+
+   if (format==GL_COLOR_INDEX) {
+      format = GL_RGBA;  /* XXXX a hack! */
+   }
+
+   switch (texUnit->EnvMode) {
+      case GL_REPLACE:
+	 switch (format) {
+	    case GL_ALPHA:
+	       for (i=0;i<n;i++) {
+		  /* Cv = Cf */
+                  /* Av = At */
+                  rgba[i][ACOMP] = texel[i][ACOMP];
+	       }
+	       break;
+	    case GL_LUMINANCE:
+	       for (i=0;i<n;i++) {
+		  /* Cv = Lt */
+                  GLchan Lt = texel[i][RCOMP];
+                  rgba[i][RCOMP] = rgba[i][GCOMP] = rgba[i][BCOMP] = Lt;
+                  /* Av = Af */
+	       }
+	       break;
+	    case GL_LUMINANCE_ALPHA:
+	       for (i=0;i<n;i++) {
+                  GLchan Lt = texel[i][RCOMP];
+		  /* Cv = Lt */
+		  rgba[i][RCOMP] = rgba[i][GCOMP] = rgba[i][BCOMP] = Lt;
+		  /* Av = At */
+		  rgba[i][ACOMP] = texel[i][ACOMP];
+	       }
+	       break;
+	    case GL_INTENSITY:
+	       for (i=0;i<n;i++) {
+		  /* Cv = It */
+                  GLchan It = texel[i][RCOMP];
+                  rgba[i][RCOMP] = rgba[i][GCOMP] = rgba[i][BCOMP] = It;
+                  /* Av = It */
+                  rgba[i][ACOMP] = It;
+	       }
+	       break;
+	    case GL_RGB:
+	       for (i=0;i<n;i++) {
+		  /* Cv = Ct */
+		  rgba[i][RCOMP] = texel[i][RCOMP];
+		  rgba[i][GCOMP] = texel[i][GCOMP];
+		  rgba[i][BCOMP] = texel[i][BCOMP];
+		  /* Av = Af */
+	       }
+	       break;
+	    case GL_RGBA:
+	       for (i=0;i<n;i++) {
+		  /* Cv = Ct */
+		  rgba[i][RCOMP] = texel[i][RCOMP];
+		  rgba[i][GCOMP] = texel[i][GCOMP];
+		  rgba[i][BCOMP] = texel[i][BCOMP];
+		  /* Av = At */
+		  rgba[i][ACOMP] = texel[i][ACOMP];
+	       }
+	       break;
+            default:
+               gl_problem(ctx, "Bad format (GL_REPLACE) in apply_texture");
+               return;
+	 }
+	 break;
+
+      case GL_MODULATE:
+         switch (format) {
+	    case GL_ALPHA:
+	       for (i=0;i<n;i++) {
+		  /* Cv = Cf */
+		  /* Av = AfAt */
+		  rgba[i][ACOMP] = CHAN_PRODUCT( rgba[i][ACOMP], texel[i][ACOMP] );
+	       }
+	       break;
+	    case GL_LUMINANCE:
+	       for (i=0;i<n;i++) {
+		  /* Cv = LtCf */
+                  GLchan Lt = texel[i][RCOMP];
+		  rgba[i][RCOMP] = CHAN_PRODUCT( rgba[i][RCOMP], Lt );
+		  rgba[i][GCOMP] = CHAN_PRODUCT( rgba[i][GCOMP], Lt );
+		  rgba[i][BCOMP] = CHAN_PRODUCT( rgba[i][BCOMP], Lt );
+		  /* Av = Af */
+	       }
+	       break;
+	    case GL_LUMINANCE_ALPHA:
+	       for (i=0;i<n;i++) {
+		  /* Cv = CfLt */
+                  GLchan Lt = texel[i][RCOMP];
+		  rgba[i][RCOMP] = CHAN_PRODUCT( rgba[i][RCOMP], Lt );
+		  rgba[i][GCOMP] = CHAN_PRODUCT( rgba[i][GCOMP], Lt );
+		  rgba[i][BCOMP] = CHAN_PRODUCT( rgba[i][BCOMP], Lt );
+		  /* Av = AfAt */
+		  rgba[i][ACOMP] = CHAN_PRODUCT( rgba[i][ACOMP], texel[i][ACOMP] );
+	       }
+	       break;
+	    case GL_INTENSITY:
+	       for (i=0;i<n;i++) {
+		  /* Cv = CfIt */
+                  GLchan It = texel[i][RCOMP];
+		  rgba[i][RCOMP] = CHAN_PRODUCT( rgba[i][RCOMP], It );
+		  rgba[i][GCOMP] = CHAN_PRODUCT( rgba[i][GCOMP], It );
+		  rgba[i][BCOMP] = CHAN_PRODUCT( rgba[i][BCOMP], It );
+		  /* Av = AfIt */
+		  rgba[i][ACOMP] = CHAN_PRODUCT( rgba[i][ACOMP], It );
+	       }
+	       break;
+	    case GL_RGB:
+	       for (i=0;i<n;i++) {
+		  /* Cv = CfCt */
+		  rgba[i][RCOMP] = CHAN_PRODUCT( rgba[i][RCOMP], texel[i][RCOMP] );
+		  rgba[i][GCOMP] = CHAN_PRODUCT( rgba[i][GCOMP], texel[i][GCOMP] );
+		  rgba[i][BCOMP] = CHAN_PRODUCT( rgba[i][BCOMP], texel[i][BCOMP] );
+		  /* Av = Af */
+	       }
+	       break;
+	    case GL_RGBA:
+	       for (i=0;i<n;i++) {
+		  /* Cv = CfCt */
+		  rgba[i][RCOMP] = CHAN_PRODUCT( rgba[i][RCOMP], texel[i][RCOMP] );
+		  rgba[i][GCOMP] = CHAN_PRODUCT( rgba[i][GCOMP], texel[i][GCOMP] );
+		  rgba[i][BCOMP] = CHAN_PRODUCT( rgba[i][BCOMP], texel[i][BCOMP] );
+		  /* Av = AfAt */
+		  rgba[i][ACOMP] = CHAN_PRODUCT( rgba[i][ACOMP], texel[i][ACOMP] );
+	       }
+	       break;
+            default:
+               gl_problem(ctx, "Bad format (GL_MODULATE) in apply_texture");
+               return;
+	 }
+	 break;
+
+      case GL_DECAL:
+         switch (format) {
+            case GL_ALPHA:
+            case GL_LUMINANCE:
+            case GL_LUMINANCE_ALPHA:
+            case GL_INTENSITY:
+               /* undefined */
+               break;
+	    case GL_RGB:
+	       for (i=0;i<n;i++) {
+		  /* Cv = Ct */
+		  rgba[i][RCOMP] = texel[i][RCOMP];
+		  rgba[i][GCOMP] = texel[i][GCOMP];
+		  rgba[i][BCOMP] = texel[i][BCOMP];
+		  /* Av = Af */
+	       }
+	       break;
+	    case GL_RGBA:
+	       for (i=0;i<n;i++) {
+		  /* Cv = Cf(1-At) + CtAt */
+		  GLint t = texel[i][ACOMP], s = CHAN_MAX - t;
+		  rgba[i][RCOMP] = CHAN_PRODUCT(rgba[i][RCOMP], s) + CHAN_PRODUCT(texel[i][RCOMP],t);
+		  rgba[i][GCOMP] = CHAN_PRODUCT(rgba[i][GCOMP], s) + CHAN_PRODUCT(texel[i][GCOMP],t);
+		  rgba[i][BCOMP] = CHAN_PRODUCT(rgba[i][BCOMP], s) + CHAN_PRODUCT(texel[i][BCOMP],t);
+		  /* Av = Af */
+	       }
+	       break;
+            default:
+               gl_problem(ctx, "Bad format (GL_DECAL) in apply_texture");
+               return;
+	 }
+	 break;
+
+      case GL_BLEND:
+         Rc = (GLint) (texUnit->EnvColor[0] * CHAN_MAXF);
+         Gc = (GLint) (texUnit->EnvColor[1] * CHAN_MAXF);
+         Bc = (GLint) (texUnit->EnvColor[2] * CHAN_MAXF);
+         Ac = (GLint) (texUnit->EnvColor[3] * CHAN_MAXF);
+	 switch (format) {
+	    case GL_ALPHA:
+	       for (i=0;i<n;i++) {
+		  /* Cv = Cf */
+		  /* Av = AfAt */
+                  rgba[i][ACOMP] = CHAN_PRODUCT(rgba[i][ACOMP], texel[i][ACOMP]);
+	       }
+	       break;
+            case GL_LUMINANCE:
+	       for (i=0;i<n;i++) {
+		  /* Cv = Cf(1-Lt) + CcLt */
+		  GLchan Lt = texel[i][RCOMP], s = CHAN_MAX - Lt;
+		  rgba[i][RCOMP] = CHAN_PRODUCT(rgba[i][RCOMP], s) + CHAN_PRODUCT(Rc, Lt);
+		  rgba[i][GCOMP] = CHAN_PRODUCT(rgba[i][GCOMP], s) + CHAN_PRODUCT(Gc, Lt);
+		  rgba[i][BCOMP] = CHAN_PRODUCT(rgba[i][BCOMP], s) + CHAN_PRODUCT(Bc, Lt);
+		  /* Av = Af */
+	       }
+	       break;
+	    case GL_LUMINANCE_ALPHA:
+	       for (i=0;i<n;i++) {
+		  /* Cv = Cf(1-Lt) + CcLt */
+		  GLchan Lt = texel[i][RCOMP], s = CHAN_MAX - Lt;
+		  rgba[i][RCOMP] = CHAN_PRODUCT(rgba[i][RCOMP], s) + CHAN_PRODUCT(Rc, Lt);
+		  rgba[i][GCOMP] = CHAN_PRODUCT(rgba[i][GCOMP], s) + CHAN_PRODUCT(Gc, Lt);
+		  rgba[i][BCOMP] = CHAN_PRODUCT(rgba[i][BCOMP], s) + CHAN_PRODUCT(Bc, Lt);
+		  /* Av = AfAt */
+		  rgba[i][ACOMP] = CHAN_PRODUCT(rgba[i][ACOMP],texel[i][ACOMP]);
+	       }
+	       break;
+            case GL_INTENSITY:
+	       for (i=0;i<n;i++) {
+		  /* Cv = Cf(1-It) + CcLt */
+		  GLchan It = texel[i][RCOMP], s = CHAN_MAX - It;
+		  rgba[i][RCOMP] = CHAN_PRODUCT(rgba[i][RCOMP], s) + CHAN_PRODUCT(Rc, It);
+		  rgba[i][GCOMP] = CHAN_PRODUCT(rgba[i][GCOMP], s) + CHAN_PRODUCT(Gc, It);
+		  rgba[i][BCOMP] = CHAN_PRODUCT(rgba[i][BCOMP], s) + CHAN_PRODUCT(Bc, It);
+                  /* Av = Af(1-It) + Ac*It */
+                  rgba[i][ACOMP] = CHAN_PRODUCT(rgba[i][ACOMP], s) + CHAN_PRODUCT(Ac, It);
+               }
+               break;
+	    case GL_RGB:
+	       for (i=0;i<n;i++) {
+		  /* Cv = Cf(1-Ct) + CcCt */
+		  rgba[i][RCOMP] = CHAN_PRODUCT(rgba[i][RCOMP], (CHAN_MAX-texel[i][RCOMP])) + CHAN_PRODUCT(Rc,texel[i][RCOMP]);
+		  rgba[i][GCOMP] = CHAN_PRODUCT(rgba[i][GCOMP], (CHAN_MAX-texel[i][GCOMP])) + CHAN_PRODUCT(Gc,texel[i][GCOMP]);
+		  rgba[i][BCOMP] = CHAN_PRODUCT(rgba[i][BCOMP], (CHAN_MAX-texel[i][BCOMP])) + CHAN_PRODUCT(Bc,texel[i][BCOMP]);
+		  /* Av = Af */
+	       }
+	       break;
+	    case GL_RGBA:
+	       for (i=0;i<n;i++) {
+		  /* Cv = Cf(1-Ct) + CcCt */
+		  rgba[i][RCOMP] = CHAN_PRODUCT(rgba[i][RCOMP], (CHAN_MAX-texel[i][RCOMP])) + CHAN_PRODUCT(Rc,texel[i][RCOMP]);
+		  rgba[i][GCOMP] = CHAN_PRODUCT(rgba[i][GCOMP], (CHAN_MAX-texel[i][GCOMP])) + CHAN_PRODUCT(Gc,texel[i][GCOMP]);
+		  rgba[i][BCOMP] = CHAN_PRODUCT(rgba[i][BCOMP], (CHAN_MAX-texel[i][BCOMP])) + CHAN_PRODUCT(Bc,texel[i][BCOMP]);
+		  /* Av = AfAt */
+		  rgba[i][ACOMP] = CHAN_PRODUCT(rgba[i][ACOMP],texel[i][ACOMP]);
+	       }
+	       break;
+            default:
+               gl_problem(ctx, "Bad format (GL_BLEND) in apply_texture");
+               return;
+	 }
+	 break;
+
+      case GL_ADD:  /* GL_EXT_texture_add_env */
+         switch (format) {
+            case GL_ALPHA:
+               for (i=0;i<n;i++) {
+                  /* Rv = Rf */
+                  /* Gv = Gf */
+                  /* Bv = Bf */
+                  rgba[i][ACOMP] = CHAN_PRODUCT(rgba[i][ACOMP], texel[i][ACOMP]);
+               }
+               break;
+            case GL_LUMINANCE:
+               for (i=0;i<n;i++) {
+                  GLuint Lt = texel[i][RCOMP];
+                  GLuint r = rgba[i][RCOMP] + Lt;
+                  GLuint g = rgba[i][GCOMP] + Lt;
+                  GLuint b = rgba[i][BCOMP] + Lt;
+                  rgba[i][RCOMP] = MIN2(r, CHAN_MAX);
+                  rgba[i][GCOMP] = MIN2(g, CHAN_MAX);
+                  rgba[i][BCOMP] = MIN2(b, CHAN_MAX);
+                  /* Av = Af */
+               }
+               break;
+            case GL_LUMINANCE_ALPHA:
+               for (i=0;i<n;i++) {
+                  GLuint Lt = texel[i][RCOMP];
+                  GLuint r = rgba[i][RCOMP] + Lt;
+                  GLuint g = rgba[i][GCOMP] + Lt;
+                  GLuint b = rgba[i][BCOMP] + Lt;
+                  rgba[i][RCOMP] = MIN2(r, CHAN_MAX);
+                  rgba[i][GCOMP] = MIN2(g, CHAN_MAX);
+                  rgba[i][BCOMP] = MIN2(b, CHAN_MAX);
+                  rgba[i][ACOMP] = CHAN_PRODUCT(rgba[i][ACOMP], texel[i][ACOMP]);
+               }
+               break;
+            case GL_INTENSITY:
+               for (i=0;i<n;i++) {
+                  GLchan It = texel[i][RCOMP];
+                  GLuint r = rgba[i][RCOMP] + It;
+                  GLuint g = rgba[i][GCOMP] + It;
+                  GLuint b = rgba[i][BCOMP] + It;
+                  GLuint a = rgba[i][ACOMP] + It;
+                  rgba[i][RCOMP] = MIN2(r, CHAN_MAX);
+                  rgba[i][GCOMP] = MIN2(g, CHAN_MAX);
+                  rgba[i][BCOMP] = MIN2(b, CHAN_MAX);
+                  rgba[i][ACOMP] = MIN2(a, CHAN_MAX);
+               }
+               break;
+	    case GL_RGB:
+	       for (i=0;i<n;i++) {
+                  GLuint r = rgba[i][RCOMP] + texel[i][RCOMP];
+                  GLuint g = rgba[i][GCOMP] + texel[i][GCOMP];
+                  GLuint b = rgba[i][BCOMP] + texel[i][BCOMP];
+		  rgba[i][RCOMP] = MIN2(r, CHAN_MAX);
+		  rgba[i][GCOMP] = MIN2(g, CHAN_MAX);
+		  rgba[i][BCOMP] = MIN2(b, CHAN_MAX);
+		  /* Av = Af */
+	       }
+	       break;
+	    case GL_RGBA:
+	       for (i=0;i<n;i++) {
+                  GLuint r = rgba[i][RCOMP] + texel[i][RCOMP];
+                  GLuint g = rgba[i][GCOMP] + texel[i][GCOMP];
+                  GLuint b = rgba[i][BCOMP] + texel[i][BCOMP];
+		  rgba[i][RCOMP] = MIN2(r, CHAN_MAX);
+		  rgba[i][GCOMP] = MIN2(g, CHAN_MAX);
+		  rgba[i][BCOMP] = MIN2(b, CHAN_MAX);
+                  rgba[i][ACOMP] = CHAN_PRODUCT(rgba[i][ACOMP], texel[i][ACOMP]);
+               }
+               break;
+            default:
+               gl_problem(ctx, "Bad format (GL_ADD) in apply_texture");
+               return;
+	 }
+	 break;
+
+      case GL_COMBINE_EXT:    /*  GL_EXT_combine_ext; we modify texel array */
+         switch (format) {
+            case GL_ALPHA:
+               for (i=0;i<n;i++)
+                  texel[i][RCOMP] = texel[i][GCOMP] = texel[i][BCOMP] = 0;
+               break;
+            case GL_LUMINANCE:
+               for (i=0;i<n;i++) {
+                  /* Cv = Lt */
+                  GLchan Lt = texel[i][RCOMP];
+                  texel[i][GCOMP] = texel[i][BCOMP] = Lt;
+                  /* Av = 1 */
+                  texel[i][ACOMP] = CHAN_MAX;
+               }
+               break;
+            case GL_LUMINANCE_ALPHA:
+               for (i=0;i<n;i++) {
+                  GLchan Lt = texel[i][RCOMP];
+                  /* Cv = Lt */
+                  texel[i][GCOMP] = texel[i][BCOMP] = Lt;
+               }
+               break;
+            case GL_INTENSITY:
+               for (i=0;i<n;i++) {
+                  /* Cv = It */
+                  GLchan It = texel[i][RCOMP];
+                  texel[i][GCOMP] = texel[i][BCOMP] = It;
+                  /* Av = It */
+                  texel[i][ACOMP] = It;
+               }
+               break;
+            case GL_RGB:
+               for (i=0;i<n;i++) {
+                  /* Av = 1 */
+                  texel[i][ACOMP] = CHAN_MAX;
+               }
+               break;
+            case GL_RGBA:  /* do nothing. */
+               break;
+            default:
+               gl_problem(ctx, "Bad format in apply_texture (GL_COMBINE_EXT)");
+               return;
+         }
+         _mesa_texture_combine(ctx, texUnit, n, primary_rgba, texel, rgba);
+         break;
+
+      default:
+         gl_problem(ctx, "Bad env mode in apply_texture");
+         return;
+   }
+}
+
+
+
+/*
+ * Apply a unit of texture mapping to the incoming fragments.
+ */
+void gl_texture_pixels( GLcontext *ctx, GLuint texUnit, GLuint n,
+                        const GLfloat s[], const GLfloat t[],
+                        const GLfloat r[], GLfloat lambda[],
+                        GLchan primary_rgba[][4], GLchan rgba[][4] )
+{
+   const GLuint mask = TEXTURE0_ANY << (texUnit * 4);
+
+   if (ctx->Texture.ReallyEnabled & mask) {
+      const struct gl_texture_unit *textureUnit = &ctx->Texture.Unit[texUnit];
+
+      if (textureUnit->Current && textureUnit->Current->SampleFunc) {
+         GLchan texel[PB_SIZE][4];
+
+	 if (textureUnit->LodBias != 0.0F) {
+	    /* apply LOD bias, but don't clamp yet */
+            GLuint i;
+	    for (i=0;i<n;i++) {
+	       lambda[i] += textureUnit->LodBias;
+	    }
+	 }
+
+         if (textureUnit->Current->MinLod != -1000.0
+             || textureUnit->Current->MaxLod != 1000.0) {
+            /* apply LOD clamping to lambda */
+            GLfloat min = textureUnit->Current->MinLod;
+            GLfloat max = textureUnit->Current->MaxLod;
+            GLuint i;
+            for (i=0;i<n;i++) {
+               GLfloat l = lambda[i];
+               lambda[i] = CLAMP(l, min, max);
+            }
+         }
+
+         /* fetch texture images from device driver, if needed */
+         if (ctx->Driver.GetTexImage) {
+            if (!_mesa_get_teximages_from_driver(ctx, textureUnit->Current)) {
+               return;
+            }
+         }
+
+         /* Sample the texture. */
+         (*textureUnit->Current->SampleFunc)( textureUnit->Current, n,
+                                             s, t, r, lambda, texel );
+
+         apply_texture( ctx, textureUnit, n, primary_rgba, texel, rgba );
+      }
+   }
+}