Fix up some fragment program texture enable issues.

Implemented TXD instruction.

8 files changed, 141 insertions, 137 deletions

diff --git a/src/mesa/main/enable.c b/src/mesa/main/enable.c
index eb46976abb..9192abd4ac 100644
--- a/src/mesa/main/enable.c
+++ b/src/mesa/main/enable.c
@@ -1,4 +1,4 @@
-/* $Id: enable.c,v 1.75 2003/03/01 01:50:20 brianp Exp $ */
+/* $Id: enable.c,v 1.76 2003/03/15 17:33:25 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -884,7 +884,7 @@ void _mesa_set_enable( GLcontext *ctx, GLenum cap, GLboolean state )
          CHECK_EXTENSION(NV_fragment_program, cap);
          if (ctx->FragmentProgram.Enabled == state)
             return;
-         FLUSH_VERTICES(ctx, _NEW_PROGRAM);
+         FLUSH_VERTICES(ctx, _NEW_PROGRAM | _NEW_TEXTURE);
          ctx->FragmentProgram.Enabled = state;
          break;
 #endif /* FEATURE_NV_fragment_program */
diff --git a/src/mesa/main/nvfragparse.c b/src/mesa/main/nvfragparse.c
index 60b15bcd06..0f75d6c36f 100644
--- a/src/mesa/main/nvfragparse.c
+++ b/src/mesa/main/nvfragparse.c
@@ -1,4 +1,4 @@
-/* $Id: nvfragparse.c,v 1.13 2003/03/14 15:40:59 brianp Exp $ */
+/* $Id: nvfragparse.c,v 1.14 2003/03/15 17:33:26 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -42,20 +42,6 @@
 #include "nvprogram.h"
 
 
-#define FRAG_ATTRIB_WPOS  0
-#define FRAG_ATTRIB_COL0  1
-#define FRAG_ATTRIB_COL1  2
-#define FRAG_ATTRIB_FOGC  3
-#define FRAG_ATTRIB_TEX0  4
-#define FRAG_ATTRIB_TEX1  5
-#define FRAG_ATTRIB_TEX2  6
-#define FRAG_ATTRIB_TEX3  7
-#define FRAG_ATTRIB_TEX4  8
-#define FRAG_ATTRIB_TEX5  9
-#define FRAG_ATTRIB_TEX6  10
-#define FRAG_ATTRIB_TEX7  11
-
-
 #define INPUT_1V     1
 #define INPUT_2V     2
 #define INPUT_3V     3
diff --git a/src/mesa/main/nvfragprog.h b/src/mesa/main/nvfragprog.h
index d7e23627a4..8d1ed13f21 100644
--- a/src/mesa/main/nvfragprog.h
+++ b/src/mesa/main/nvfragprog.h
@@ -1,4 +1,4 @@
-/* $Id: nvfragprog.h,v 1.4 2003/03/14 15:40:59 brianp Exp $ */
+/* $Id: nvfragprog.h,v 1.5 2003/03/15 17:33:26 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -36,6 +36,21 @@
 #include "config.h"
 
 
+/* Fragment input registers / attributes */
+#define FRAG_ATTRIB_WPOS  0
+#define FRAG_ATTRIB_COL0  1
+#define FRAG_ATTRIB_COL1  2
+#define FRAG_ATTRIB_FOGC  3
+#define FRAG_ATTRIB_TEX0  4
+#define FRAG_ATTRIB_TEX1  5
+#define FRAG_ATTRIB_TEX2  6
+#define FRAG_ATTRIB_TEX3  7
+#define FRAG_ATTRIB_TEX4  8
+#define FRAG_ATTRIB_TEX5  9
+#define FRAG_ATTRIB_TEX6  10
+#define FRAG_ATTRIB_TEX7  11
+
+
 /* Location of register sets within the whole register file */
 #define FP_INPUT_REG_START  0
 #define FP_INPUT_REG_END    (FP_INPUT_REG_START + MAX_NV_FRAGMENT_PROGRAM_INPUTS - 1)
diff --git a/src/mesa/main/state.c b/src/mesa/main/state.c
index 1051bda11d..f4f6a1cb6e 100644
--- a/src/mesa/main/state.c
+++ b/src/mesa/main/state.c
@@ -1,4 +1,4 @@
-/* $Id: state.c,v 1.99 2003/03/01 01:50:22 brianp Exp $ */
+/* $Id: state.c,v 1.100 2003/03/15 17:33:26 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -813,17 +813,26 @@ update_texture_state( GLcontext *ctx )
     */
    for (unit = 0; unit < ctx->Const.MaxTextureUnits; unit++) {
       struct gl_texture_unit *texUnit = &ctx->Texture.Unit[unit];
+      GLuint enableBits;
 
       texUnit->_ReallyEnabled = 0;
       texUnit->_GenFlags = 0;
 
-      if (!texUnit->Enabled)
-	 continue;
+      /* Get the bitmask of texture enables */
+      if (ctx->FragmentProgram.Enabled && ctx->FragmentProgram.Current) {
+         enableBits = ctx->FragmentProgram.Current->TexturesUsed[unit];
+      }
+      else {
+         if (!texUnit->Enabled)
+            continue;
+         enableBits = texUnit->Enabled;
+      }
 
       /* Look for the highest-priority texture target that's enabled and
-       * complete.  That's the one we'll use for texturing.
+       * complete.  That's the one we'll use for texturing.  If we're using
+       * a fragment program we're guaranteed that bitcount(enabledBits) <= 1.
        */
-      if (texUnit->Enabled & TEXTURE_CUBE_BIT) {
+      if (enableBits & TEXTURE_CUBE_BIT) {
          struct gl_texture_object *texObj = texUnit->CurrentCubeMap;
          if (!texObj->Complete) {
             _mesa_test_texobj_completeness(ctx, texObj);
@@ -834,7 +843,7 @@ update_texture_state( GLcontext *ctx )
          }
       }
 
-      if (!texUnit->_ReallyEnabled && (texUnit->Enabled & TEXTURE_3D_BIT)) {
+      if (!texUnit->_ReallyEnabled && (enableBits & TEXTURE_3D_BIT)) {
          struct gl_texture_object *texObj = texUnit->Current3D;
          if (!texObj->Complete) {
             _mesa_test_texobj_completeness(ctx, texObj);
@@ -845,7 +854,7 @@ update_texture_state( GLcontext *ctx )
          }
       }
 
-      if (!texUnit->_ReallyEnabled && (texUnit->Enabled & TEXTURE_RECT_BIT)) {
+      if (!texUnit->_ReallyEnabled && (enableBits & TEXTURE_RECT_BIT)) {
          struct gl_texture_object *texObj = texUnit->CurrentRect;
          if (!texObj->Complete) {
             _mesa_test_texobj_completeness(ctx, texObj);
@@ -856,7 +865,7 @@ update_texture_state( GLcontext *ctx )
          }
       }
 
-      if (!texUnit->_ReallyEnabled && (texUnit->Enabled & TEXTURE_2D_BIT)) {
+      if (!texUnit->_ReallyEnabled && (enableBits & TEXTURE_2D_BIT)) {
          struct gl_texture_object *texObj = texUnit->Current2D;
          if (!texObj->Complete) {
             _mesa_test_texobj_completeness(ctx, texObj);
@@ -867,7 +876,7 @@ update_texture_state( GLcontext *ctx )
          }
       }
 
-      if (!texUnit->_ReallyEnabled && (texUnit->Enabled & TEXTURE_1D_BIT)) {
+      if (!texUnit->_ReallyEnabled && (enableBits & TEXTURE_1D_BIT)) {
          struct gl_texture_object *texObj = texUnit->Current1D;
          if (!texObj->Complete) {
             _mesa_test_texobj_completeness(ctx, texObj);
diff --git a/src/mesa/swrast/s_context.c b/src/mesa/swrast/s_context.c
index 6ed0c42e4d..29b73df365 100644
--- a/src/mesa/swrast/s_context.c
+++ b/src/mesa/swrast/s_context.c
@@ -1,4 +1,4 @@
-/* $Id: s_context.c,v 1.46 2003/03/14 15:41:00 brianp Exp $ */
+/* $Id: s_context.c,v 1.47 2003/03/15 17:33:27 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -306,35 +306,6 @@ _swrast_validate_texture_sample( GLcontext *ctx, GLuint texUnit,
       }
    }
 
-   if (ctx->FragmentProgram.Enabled) {
-      ASSERT(ctx->FragmentProgram.Current);
-      /* only one target can be referenced per unit per fragment program */
-      switch (ctx->FragmentProgram.Current->TexturesUsed[texUnit]) {
-      case TEXTURE_1D_BIT:
-         tObj = ctx->Texture.Unit[texUnit].Current1D;
-         break;
-      case TEXTURE_2D_BIT:
-         tObj = ctx->Texture.Unit[texUnit].Current2D;
-         break;
-      case TEXTURE_3D_BIT:
-         tObj = ctx->Texture.Unit[texUnit].Current3D;
-         break;
-      case TEXTURE_CUBE_BIT:
-         tObj = ctx->Texture.Unit[texUnit].CurrentCubeMap;
-         break;
-      case TEXTURE_RECT_BIT:
-         tObj = ctx->Texture.Unit[texUnit].CurrentRect;
-         break;
-      default:
-         _mesa_problem(ctx, "Bad texture in _swrast_validate_texture_sample");
-         return;
-      }
-      if (!tObj->Complete) {
-         _mesa_test_texobj_completeness(ctx,
-                                        (struct gl_texture_object *) tObj );
-      }
-   }
-
    swrast->TextureSample[texUnit] =
       _swrast_choose_texture_sample_func( ctx, tObj );
 
diff --git a/src/mesa/swrast/s_nvfragprog.c b/src/mesa/swrast/s_nvfragprog.c
index c55080c0aa..b139b8cc55 100644
--- a/src/mesa/swrast/s_nvfragprog.c
+++ b/src/mesa/swrast/s_nvfragprog.c
@@ -1,4 +1,4 @@
-/* $Id: s_nvfragprog.c,v 1.7 2003/03/14 15:41:00 brianp Exp $ */
+/* $Id: s_nvfragprog.c,v 1.8 2003/03/15 17:33:27 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -33,6 +33,7 @@
 #include "macros.h"
 
 #include "s_nvfragprog.h"
+#include "s_span.h"
 #include "s_texture.h"
 
 
@@ -46,30 +47,9 @@ fetch_texel( GLcontext *ctx, const GLfloat texcoord[4], GLuint unit,
    const GLfloat *lambda = NULL;
    GLchan rgba[4];
    SWcontext *swrast = SWRAST_CONTEXT(ctx);
-   const struct gl_texture_object *texObj = NULL;
-
-   switch (targetBit) {
-      case TEXTURE_1D_BIT:
-         texObj = ctx->Texture.Unit[unit].Current1D;
-         break;
-      case TEXTURE_2D_BIT:
-         texObj = ctx->Texture.Unit[unit].Current2D;
-         break;
-      case TEXTURE_3D_BIT:
-         texObj = ctx->Texture.Unit[unit].Current3D;
-         break;
-      case TEXTURE_CUBE_BIT:
-         texObj = ctx->Texture.Unit[unit].CurrentCubeMap;
-         break;
-      case TEXTURE_RECT_BIT:
-         texObj = ctx->Texture.Unit[unit].CurrentRect;
-         break;
-      default:
-         _mesa_problem(ctx, "Invalid target in fetch_texel");
-   }
 
-   swrast->TextureSample[unit](ctx, unit, texObj, 1,
-                               (const GLfloat (*)[4]) texcoord,
+   swrast->TextureSample[unit](ctx, unit, ctx->Texture.Unit[unit]._Current,
+                               1, (const GLfloat (*)[4]) texcoord,
                                lambda, &rgba);
    color[0] = CHAN_TO_FLOAT(rgba[0]);
    color[1] = CHAN_TO_FLOAT(rgba[1]);
@@ -83,11 +63,30 @@ fetch_texel( GLcontext *ctx, const GLfloat texcoord[4], GLuint unit,
  */
 static void
 fetch_texel_deriv( GLcontext *ctx, const GLfloat texcoord[4],
-                   const GLfloat dtdx[4], const GLfloat dtdy[4],
+                   const GLfloat texdx[4], const GLfloat texdy[4],
                    GLuint unit, GLuint targetBit, GLfloat color[4] )
 {
-   /* XXX to do */
+   SWcontext *swrast = SWRAST_CONTEXT(ctx);
+   const struct gl_texture_object *texObj = ctx->Texture.Unit[unit]._Current;
+   const struct gl_texture_image *texImg = texObj->Image[texObj->BaseLevel];
+   const GLfloat texW = (GLfloat) texImg->WidthScale;
+   const GLfloat texH = (GLfloat) texImg->HeightScale;
+   GLchan rgba[4];
 
+   GLfloat lambda = _mesa_compute_lambda(texdx[0], texdy[0], /* ds/dx, ds/dy */
+                                         texdx[1], texdy[1], /* dt/dx, dt/dy */
+                                         texdx[3], texdy[2], /* dq/dx, dq/dy */
+                                         texW, texH,
+                                         texcoord[0], texcoord[1], texcoord[3],
+                                         1.0F / texcoord[3]);
+
+   swrast->TextureSample[unit](ctx, unit, ctx->Texture.Unit[unit]._Current,
+                               1, (const GLfloat (*)[4]) texcoord,
+                               &lambda, &rgba);
+   color[0] = CHAN_TO_FLOAT(rgba[0]);
+   color[1] = CHAN_TO_FLOAT(rgba[1]);
+   color[2] = CHAN_TO_FLOAT(rgba[2]);
+   color[3] = CHAN_TO_FLOAT(rgba[3]);
 }
 
 
@@ -300,6 +299,15 @@ execute_program(GLcontext *ctx, const struct fragment_program *program)
             {
                GLfloat a[4], result[4];
                fetch_vector4( &inst->SrcReg[0], machine, a );
+               /* XXX - UGH! this is going to be a mess to implement!
+                * If we need the partial derivative of a texture coord
+                * or color, that's not too bad, but for an arbitrary register
+                * this will require a recursive solution.  That is, we'll have
+                * to run another instance of this program with WPOS.x or .y
+                * incremented by one, stopping at the preceeding instruction.
+                * Then, read the register from that other instance and compute
+                * the difference.  Yuck!
+                */
                result[0] = 0; /* XXX fix */
                result[1] = 0;
                result[2] = 0;
@@ -701,6 +709,7 @@ execute_program(GLcontext *ctx, const struct fragment_program *program)
             {
                GLfloat texcoord[4], color[4];
                fetch_vector4( &inst->SrcReg[0], machine, texcoord );
+               /* XXX: Undo perspective divide from interpolate_texcoords() */
                fetch_texel( ctx, texcoord, inst->TexSrcUnit,
                             inst->TexSrcBit, color );
                store_vector4( inst, machine, color );
@@ -723,9 +732,7 @@ execute_program(GLcontext *ctx, const struct fragment_program *program)
             {
                GLfloat texcoord[4], color[4];
                fetch_vector4( &inst->SrcReg[0], machine, texcoord );
-               texcoord[0] /= texcoord[3];
-               texcoord[1] /= texcoord[3];
-               texcoord[2] /= texcoord[3];
+               /* Already did perspective divide in interpolate_texcoords() */
                fetch_texel( ctx, texcoord, inst->TexSrcUnit,
                             inst->TexSrcBit, color );
                store_vector4( inst, machine, color );
@@ -807,56 +814,63 @@ execute_program(GLcontext *ctx, const struct fragment_program *program)
 void
 _swrast_exec_nv_fragment_program( GLcontext *ctx, struct sw_span *span )
 {
+   const struct fragment_program *program = ctx->FragmentProgram.Current;
    GLuint i;
 
    for (i = 0; i < span->end; i++) {
       if (span->array->mask[i]) {
-         GLfloat *wpos = ctx->FragmentProgram.Machine.Registers[0];
-         GLfloat *col0 = ctx->FragmentProgram.Machine.Registers[1];
-         GLfloat *col1 = ctx->FragmentProgram.Machine.Registers[2];
-         GLfloat *fogc = ctx->FragmentProgram.Machine.Registers[3];
          const GLfloat *colOut = ctx->FragmentProgram.Machine.Registers[FP_OUTPUT_REG_START];
-         GLuint j;
+         GLuint u;
 
-         /* Clear temporary registers XXX use memzero() */
+         /* Clear temporary registers */
          _mesa_bzero(ctx->FragmentProgram.Machine.Registers +FP_TEMP_REG_START,
                      MAX_NV_FRAGMENT_PROGRAM_TEMPS * 4 * sizeof(GLfloat));
 
          /*
           * Load input registers - yes this is all very inefficient for now.
           */
-         wpos[0] = span->x + i;
-         wpos[1] = span->y + i;
-         wpos[2] = (GLfloat) span->array->z[i] / ctx->DepthMaxF;
-         wpos[3] = 1.0; /* XXX should be 1/w */
-
-         col0[0] = CHAN_TO_FLOAT(span->array->rgba[i][RCOMP]);
-         col0[1] = CHAN_TO_FLOAT(span->array->rgba[i][GCOMP]);
-         col0[2] = CHAN_TO_FLOAT(span->array->rgba[i][BCOMP]);
-         col0[3] = CHAN_TO_FLOAT(span->array->rgba[i][ACOMP]);
-
-         col1[0] = CHAN_TO_FLOAT(span->array->spec[i][RCOMP]);
-         col1[1] = CHAN_TO_FLOAT(span->array->spec[i][GCOMP]);
-         col1[2] = CHAN_TO_FLOAT(span->array->spec[i][BCOMP]);
-         col1[3] = CHAN_TO_FLOAT(span->array->spec[i][ACOMP]);
-
-         fogc[0] = span->array->fog[i];
-         fogc[1] = 0.0F;
-         fogc[2] = 0.0F;
-         fogc[3] = 0.0F;
-
-         for (j = 0; j < ctx->Const.MaxTextureCoordUnits; j++) {
-            if (ctx->Texture.Unit[j]._ReallyEnabled) {
-               COPY_4V(ctx->FragmentProgram.Machine.Registers[4 + j],
-                       span->array->texcoords[j][i]);
-            }
-            else {
-               COPY_4V(ctx->FragmentProgram.Machine.Registers[4 + j],
-                       ctx->Current.Attrib[VERT_ATTRIB_TEX0 + j]);
+         if (program->InputsRead & (1 << FRAG_ATTRIB_WPOS)) {
+            GLfloat *wpos = ctx->FragmentProgram.Machine.Registers[0];
+            wpos[0] = span->x + i;
+            wpos[1] = span->y + i;
+            wpos[2] = (GLfloat) span->array->z[i] / ctx->DepthMaxF;
+            wpos[3] = 1.0; /* XXX should be 1/w */
+         }
+         if (program->InputsRead & (1 << FRAG_ATTRIB_COL0)) {
+            GLfloat *col0 = ctx->FragmentProgram.Machine.Registers[1];
+            col0[0] = CHAN_TO_FLOAT(span->array->rgba[i][RCOMP]);
+            col0[1] = CHAN_TO_FLOAT(span->array->rgba[i][GCOMP]);
+            col0[2] = CHAN_TO_FLOAT(span->array->rgba[i][BCOMP]);
+            col0[3] = CHAN_TO_FLOAT(span->array->rgba[i][ACOMP]);
+         }
+         if (program->InputsRead & (1 << FRAG_ATTRIB_COL1)) {
+            GLfloat *col1 = ctx->FragmentProgram.Machine.Registers[2];
+            col1[0] = CHAN_TO_FLOAT(span->array->spec[i][RCOMP]);
+            col1[1] = CHAN_TO_FLOAT(span->array->spec[i][GCOMP]);
+            col1[2] = CHAN_TO_FLOAT(span->array->spec[i][BCOMP]);
+            col1[3] = CHAN_TO_FLOAT(span->array->spec[i][ACOMP]);
+         }
+         if (program->InputsRead & (1 << FRAG_ATTRIB_FOGC)) {
+            GLfloat *fogc = ctx->FragmentProgram.Machine.Registers[3];
+            fogc[0] = span->array->fog[i];
+            fogc[1] = 0.0F;
+            fogc[2] = 0.0F;
+            fogc[3] = 0.0F;
+         }
+         for (u = 0; u < ctx->Const.MaxTextureCoordUnits; u++) {
+            if (program->InputsRead & (1 << (FRAG_ATTRIB_TEX0 + u))) {
+               if (ctx->Texture.Unit[u]._ReallyEnabled) {
+                  COPY_4V(ctx->FragmentProgram.Machine.Registers[4 + u],
+                          span->array->texcoords[u][i]);
+               }
+               else {
+                  COPY_4V(ctx->FragmentProgram.Machine.Registers[4 + u],
+                          ctx->Current.Attrib[VERT_ATTRIB_TEX0 + u]);
+               }
             }
          }
 
-         if (!execute_program(ctx, ctx->FragmentProgram.Current))
+         if (!execute_program(ctx, program))
             span->array->mask[i] = GL_FALSE;  /* killed fragment */
 
          /* Store output registers */
diff --git a/src/mesa/swrast/s_span.c b/src/mesa/swrast/s_span.c
index 2106b87c5b..cb02ab924d 100644
--- a/src/mesa/swrast/s_span.c
+++ b/src/mesa/swrast/s_span.c
@@ -1,4 +1,4 @@
-/* $Id: s_span.c,v 1.57 2003/03/04 16:34:03 brianp Exp $ */
+/* $Id: s_span.c,v 1.58 2003/03/15 17:33:27 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -321,10 +321,10 @@ compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy,
 /*
  * This is a faster approximation
  */
-static GLfloat
-compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy,
-               GLfloat dqdx, GLfloat dqdy, GLfloat texW, GLfloat texH,
-               GLfloat s, GLfloat t, GLfloat q, GLfloat invQ)
+GLfloat
+_mesa_compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy,
+                     GLfloat dqdx, GLfloat dqdy, GLfloat texW, GLfloat texH,
+                     GLfloat s, GLfloat t, GLfloat q, GLfloat invQ)
 {
    GLfloat dsdx2 = (s + dsdx) / (q + dqdx) - s * invQ;
    GLfloat dtdx2 = (t + dtdx) / (q + dqdx) - t * invQ;
@@ -361,7 +361,8 @@ interpolate_texcoords(GLcontext *ctx, struct sw_span *span)
          if (ctx->Texture.Unit[u]._ReallyEnabled) {
             const struct gl_texture_object *obj =ctx->Texture.Unit[u]._Current;
             const struct gl_texture_image *img = obj->Image[obj->BaseLevel];
-            GLboolean needLambda = (obj->MinFilter != obj->MagFilter);
+            const GLboolean needLambda = (obj->MinFilter != obj->MagFilter)
+               || ctx->FragmentProgram.Enabled;
             if (needLambda) {
                GLfloat (*texcoord)[4] = span->array->texcoords[u];
                GLfloat *lambda = span->array->lambda[u];
@@ -384,9 +385,10 @@ interpolate_texcoords(GLcontext *ctx, struct sw_span *span)
                   texcoord[i][0] = s * invQ;
                   texcoord[i][1] = t * invQ;
                   texcoord[i][2] = r * invQ;
-                  lambda[i] = compute_lambda(dsdx, dsdy, dtdx, dtdy,
-                                             dqdx, dqdy, texW, texH,
-                                             s, t, q, invQ);
+                  texcoord[i][3] = q;
+                  lambda[i] = _mesa_compute_lambda(dsdx, dsdy, dtdx, dtdy,
+                                                   dqdx, dqdy, texW, texH,
+                                                   s, t, q, invQ);
                   s += dsdx;
                   t += dtdx;
                   r += drdx;
@@ -440,7 +442,8 @@ interpolate_texcoords(GLcontext *ctx, struct sw_span *span)
       /* single texture */
       const struct gl_texture_object *obj = ctx->Texture.Unit[0]._Current;
       const struct gl_texture_image *img = obj->Image[obj->BaseLevel];
-      GLboolean needLambda = (obj->MinFilter != obj->MagFilter);
+      const GLboolean needLambda = (obj->MinFilter != obj->MagFilter)
+         || ctx->FragmentProgram.Enabled;
       span->arrayMask |= SPAN_TEXTURE;
       if (needLambda) {
          /* just texture unit 0, with lambda */
@@ -462,12 +465,13 @@ interpolate_texcoords(GLcontext *ctx, struct sw_span *span)
          GLuint i;
          for (i = 0; i < span->end; i++) {
             const GLfloat invQ = (q == 0.0F) ? 1.0F : (1.0F / q);
-            lambda[i] = compute_lambda(dsdx, dsdy, dtdx, dtdy,
-                                       dqdx, dqdy, texW, texH,
-                                       s, t, q, invQ);
+            lambda[i] = _mesa_compute_lambda(dsdx, dsdy, dtdx, dtdy,
+                                             dqdx, dqdy, texW, texH,
+                                             s, t, q, invQ);
             texcoord[i][0] = s * invQ;
             texcoord[i][1] = t * invQ;
             texcoord[i][2] = r * invQ;
+            texcoord[i][3] = q;
             s += dsdx;
             t += dtdx;
             r += drdx;
diff --git a/src/mesa/swrast/s_span.h b/src/mesa/swrast/s_span.h
index be577ed6e5..d43aa1ae39 100644
--- a/src/mesa/swrast/s_span.h
+++ b/src/mesa/swrast/s_span.h
@@ -1,10 +1,10 @@
-/* $Id: s_span.h,v 1.17 2002/06/15 02:38:17 brianp Exp $ */
+/* $Id: s_span.h,v 1.18 2003/03/15 17:33:28 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
- * Version:  4.1
+ * Version:  5.1
  *
- * Copyright (C) 1999-2002  Brian Paul   All Rights Reserved.
+ * Copyright (C) 1999-2003  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"),
@@ -48,6 +48,11 @@ _mesa_span_default_color( GLcontext *ctx, struct sw_span *span );
 extern void
 _mesa_span_default_texcoords( GLcontext *ctx, struct sw_span *span );
 
+extern GLfloat
+_mesa_compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy,
+                     GLfloat dqdx, GLfloat dqdy, GLfloat texW, GLfloat texH,
+                     GLfloat s, GLfloat t, GLfloat q, GLfloat invQ);
+
 extern void
 _mesa_write_index_span( GLcontext *ctx, struct sw_span *span);