Initial revision

1 files changed, 327 insertions, 0 deletions

diff --git a/src/mesa/main/fog.c b/src/mesa/main/fog.c
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+++ b/src/mesa/main/fog.c
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+/* $Id: fog.c,v 1.1 1999/08/19 00:55:41 jtg Exp $ */
+
+/*
+ * Mesa 3-D graphics library
+ * Version:  3.1
+ * 
+ * Copyright (C) 1999  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.
+ */
+
+
+#ifdef PC_HEADER
+#include "all.h"
+#else
+#include <math.h>
+#include <stdlib.h>
+#include "context.h"
+#include "fog.h"
+#include "macros.h"
+#include "mmath.h"
+#include "types.h"
+#ifdef XFree86Server
+#include "GL/xf86glx.h"
+#endif
+#endif
+
+
+
+void gl_Fogfv( GLcontext *ctx, GLenum pname, const GLfloat *params )
+{
+   GLenum m;
+
+   switch (pname) {
+      case GL_FOG_MODE:
+         m = (GLenum) (GLint) *params;
+	 if (m==GL_LINEAR || m==GL_EXP || m==GL_EXP2) {
+	    ctx->Fog.Mode = m;
+	 }
+	 else {
+	    gl_error( ctx, GL_INVALID_ENUM, "glFog" );
+            return;
+	 }
+	 break;
+      case GL_FOG_DENSITY:
+	 if (*params<0.0) {
+	    gl_error( ctx, GL_INVALID_VALUE, "glFog" );
+            return;
+	 }
+	 else {
+	    ctx->Fog.Density = *params;
+	 }
+	 break;
+      case GL_FOG_START:
+#if 0
+         /* Prior to OpenGL 1.1, this was an error */
+         if (*params<0.0F) {
+            gl_error( ctx, GL_INVALID_VALUE, "glFog(GL_FOG_START)" );
+            return;
+         }
+#endif
+	 ctx->Fog.Start = *params;
+	 break;
+      case GL_FOG_END:
+#if 0
+         /* Prior to OpenGL 1.1, this was an error */
+         if (*params<0.0F) {
+            gl_error( ctx, GL_INVALID_VALUE, "glFog(GL_FOG_END)" );
+            return;
+         }
+#endif
+	 ctx->Fog.End = *params;
+	 break;
+      case GL_FOG_INDEX:
+	 ctx->Fog.Index = *params;
+	 break;
+      case GL_FOG_COLOR:
+	 ctx->Fog.Color[0] = params[0];
+	 ctx->Fog.Color[1] = params[1];
+	 ctx->Fog.Color[2] = params[2];
+	 ctx->Fog.Color[3] = params[3];
+         break;
+      default:
+         gl_error( ctx, GL_INVALID_ENUM, "glFog" );
+         return;
+   }
+
+   if (ctx->Driver.Fogfv) {
+      (*ctx->Driver.Fogfv)( ctx, pname, params );
+   }
+
+   ctx->NewState |= NEW_FOG;
+}
+
+
+typedef void (*fog_func)( struct vertex_buffer *VB, GLuint side, 
+			  GLubyte flag );
+
+
+static fog_func fog_ci_tab[2];
+static fog_func fog_rgba_tab[2];
+
+/*
+ * Compute the fogged color for an array of vertices.
+ * Input:  n - number of vertices
+ *         v - array of vertices
+ *         color - the original vertex colors
+ * Output:  color - the fogged colors
+ * 
+ */
+#define TAG(x) x##_raw
+#define CULLCHECK
+#define IDX 0
+#include "fog_tmp.h"
+
+#define TAG(x) x##_masked
+#define CULLCHECK if (cullmask[i]&flag)
+#define IDX 1
+#include "fog_tmp.h"
+
+void gl_init_fog( void )
+{
+   init_fog_tab_masked();
+   init_fog_tab_raw();
+}
+
+/*
+ * Compute fog for the vertices in the vertex buffer.
+ */
+void gl_fog_vertices( struct vertex_buffer *VB )
+{
+   GLcontext *ctx = VB->ctx;
+   GLuint i = VB->CullMode & 1;
+
+   if (ctx->Visual->RGBAflag) {
+      /* Fog RGB colors */
+      if (ctx->TriangleCaps & DD_TRI_LIGHT_TWOSIDE) {
+	 fog_rgba_tab[i]( VB, 0, VERT_FACE_FRONT );
+	 fog_rgba_tab[i]( VB, 1, VERT_FACE_REAR );
+      } else {
+	 fog_rgba_tab[i]( VB, 0, VERT_FACE_FRONT|VERT_FACE_REAR );
+      }
+   }
+   else {
+      /* Fog color indexes */
+      if (ctx->TriangleCaps & DD_TRI_LIGHT_TWOSIDE) {
+	 fog_ci_tab[i]( VB, 0, VERT_FACE_FRONT );
+         fog_ci_tab[i]( VB, 1, VERT_FACE_REAR );
+      } else {
+	 fog_ci_tab[i]( VB, 0, VERT_FACE_FRONT|VERT_FACE_REAR );
+      }
+   }
+}
+
+/*
+ * Apply fog to an array of RGBA pixels.
+ * Input:  n - number of pixels
+ *         z - array of integer depth values
+ *         red, green, blue, alpha - pixel colors
+ * Output:  red, green, blue, alpha - fogged pixel colors
+ */
+void gl_fog_rgba_pixels( const GLcontext *ctx,
+                         GLuint n, const GLdepth z[], GLubyte rgba[][4] )
+{
+   GLfloat c = ctx->ProjectionMatrix.m[10];
+   GLfloat d = ctx->ProjectionMatrix.m[14];
+   GLuint i;
+
+   GLfloat rFog = ctx->Fog.Color[0] * 255.0F;
+   GLfloat gFog = ctx->Fog.Color[1] * 255.0F;
+   GLfloat bFog = ctx->Fog.Color[2] * 255.0F;
+
+   GLfloat tz = ctx->Viewport.WindowMap.m[MAT_TZ];
+   GLfloat szInv = 1.0F / ctx->Viewport.WindowMap.m[MAT_SZ];
+
+   switch (ctx->Fog.Mode) {
+      case GL_LINEAR:
+         {
+            GLfloat fogEnd = ctx->Fog.End;
+            GLfloat fogScale = 1.0F / (ctx->Fog.End - ctx->Fog.Start);
+            for (i=0;i<n;i++) {
+               GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
+               GLfloat eyez = -d / (c+ndcz);
+               GLfloat f, g;
+               if (eyez < 0.0)  eyez = -eyez;
+               f = (fogEnd - eyez) * fogScale;
+               f = CLAMP( f, 0.0F, 1.0F );
+               g = 1.0F - f;
+               rgba[i][RCOMP] = (GLint) (f * rgba[i][RCOMP] + g * rFog);
+               rgba[i][GCOMP] = (GLint) (f * rgba[i][GCOMP] + g * gFog);
+               rgba[i][BCOMP] = (GLint) (f * rgba[i][BCOMP] + g * bFog);
+            }
+         }
+	 break;
+      case GL_EXP:
+	 for (i=0;i<n;i++) {
+	    GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
+	    GLfloat eyez = d / (c+ndcz);
+            GLfloat f, g;
+	    if (eyez < 0.0)
+               eyez = -eyez;
+	    f = exp( -ctx->Fog.Density * eyez );
+            g = 1.0F - f;
+            rgba[i][RCOMP] = (GLint) (f * rgba[i][RCOMP] + g * rFog);
+            rgba[i][GCOMP] = (GLint) (f * rgba[i][GCOMP] + g * gFog);
+            rgba[i][BCOMP] = (GLint) (f * rgba[i][BCOMP] + g * bFog);
+	 }
+	 break;
+      case GL_EXP2:
+         {
+            GLfloat negDensitySquared = -ctx->Fog.Density * ctx->Fog.Density;
+            for (i=0;i<n;i++) {
+               GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
+               GLfloat eyez = d / (c+ndcz);
+               GLfloat f, g;
+               GLfloat tmp = negDensitySquared * eyez * eyez;
+#ifdef __alpha__
+               /* XXX this underflow check may be needed for other systems */
+               if (tmp < FLT_MIN_10_EXP)
+                  f = exp( FLT_MIN_10_EXP );
+               else
+#endif
+                  f = exp( tmp );
+               g = 1.0F - f;
+               rgba[i][RCOMP] = (GLint) (f * rgba[i][RCOMP] + g * rFog);
+               rgba[i][GCOMP] = (GLint) (f * rgba[i][GCOMP] + g * gFog);
+               rgba[i][BCOMP] = (GLint) (f * rgba[i][BCOMP] + g * bFog);
+            }
+         }
+	 break;
+      default:
+         gl_problem(ctx, "Bad fog mode in gl_fog_rgba_pixels");
+         return;
+   }
+}
+
+
+
+
+/*
+ * Apply fog to an array of color index pixels.
+ * Input:  n - number of pixels
+ *         z - array of integer depth values
+ *         index - pixel color indexes
+ * Output:  index - fogged pixel color indexes
+ */
+void gl_fog_ci_pixels( const GLcontext *ctx,
+                       GLuint n, const GLdepth z[], GLuint index[] )
+{
+   GLfloat c = ctx->ProjectionMatrix.m[10];
+   GLfloat d = ctx->ProjectionMatrix.m[14];
+   GLuint i;
+
+   GLfloat tz = ctx->Viewport.WindowMap.m[MAT_TZ];
+   GLfloat szInv = 1.0F / ctx->Viewport.WindowMap.m[MAT_SZ];
+
+   switch (ctx->Fog.Mode) {
+      case GL_LINEAR:
+         {
+            GLfloat fogEnd = ctx->Fog.End;
+            GLfloat fogScale = 1.0F / (ctx->Fog.End - ctx->Fog.Start);
+            for (i=0;i<n;i++) {
+               GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
+               GLfloat eyez = -d / (c+ndcz);
+               GLfloat f;
+               if (eyez < 0.0)  eyez = -eyez;
+               f = (fogEnd - eyez) * fogScale;
+               f = CLAMP( f, 0.0F, 1.0F );
+               index[i] = (GLuint) ((GLfloat) index[i] + (1.0F-f) * ctx->Fog.Index);
+            }
+	 }
+	 break;
+      case GL_EXP:
+         for (i=0;i<n;i++) {
+	    GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
+	    GLfloat eyez = -d / (c+ndcz);
+            GLfloat f;
+	    if (eyez < 0.0)
+               eyez = -eyez;
+	    f = exp( -ctx->Fog.Density * eyez );
+	    f = CLAMP( f, 0.0F, 1.0F );
+	    index[i] = (GLuint) ((GLfloat) index[i] + (1.0F-f) * ctx->Fog.Index);
+	 }
+	 break;
+      case GL_EXP2:
+         {
+            GLfloat negDensitySquared = -ctx->Fog.Density * ctx->Fog.Density;
+            for (i=0;i<n;i++) {
+               GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
+               GLfloat eyez = -d / (c+ndcz);
+               GLfloat tmp, f;
+               if (eyez < 0.0)
+                  eyez = -eyez;
+               tmp = negDensitySquared * eyez * eyez;
+#ifdef __alpha__
+               /* XXX this underflow check may be needed for other systems */
+               if (tmp < FLT_MIN_10_EXP)
+                  f = exp( FLT_MIN_10_EXP );
+               else
+#endif
+               f = exp( tmp );
+               f = CLAMP( f, 0.0F, 1.0F );
+               index[i] = (GLuint) ((GLfloat) index[i] + (1.0F-f) * ctx->Fog.Index);
+            }
+	 }
+	 break;
+      default:
+         gl_problem(ctx, "Bad fog mode in gl_fog_ci_pixels");
+         return;
+   }
+}
+