Refactor "class" texture environments to be implemented in terms of

ARB_texture_env_combine state.

1 files changed, 291 insertions, 96 deletions

diff --git a/src/mesa/main/texstate.c b/src/mesa/main/texstate.c
index e27c42e07b6..8cb247e413b 100644
--- a/src/mesa/main/texstate.c
+++ b/src/mesa/main/texstate.c
@@ -22,6 +22,11 @@
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
+/** 
+ * \file texstate.c
+ *
+ * Texture state handling.
+ */
 
 #include "glheader.h"
 #include "colormac.h"
@@ -50,6 +55,20 @@
 #define ENUM_TO_DOUBLE(X) ((GLdouble)(X))
 #endif
 
+/**
+ * Default texture combine environment state.  This is used to initialize
+ * a context's texture units and as the basis for converting "classic"
+ * texture environmnets to ARB_texture_env_combine style values.
+ */
+static const struct gl_tex_env_combine_state default_combine_state = {
+   GL_MODULATE, GL_MODULATE,
+   { GL_TEXTURE, GL_PREVIOUS, GL_CONSTANT },
+   { GL_TEXTURE, GL_PREVIOUS, GL_CONSTANT },
+   { GL_SRC_COLOR, GL_SRC_COLOR, GL_SRC_ALPHA },
+   { GL_SRC_ALPHA, GL_SRC_ALPHA, GL_SRC_ALPHA },
+   0, 0,
+   2, 2
+};
 
 
 void
@@ -92,14 +111,14 @@ _mesa_copy_texture_state( const GLcontext *src, GLcontext *dst )
       dst->Texture.Unit[i].LodBias = src->Texture.Unit[i].LodBias;
 
       /* GL_EXT_texture_env_combine */
-      dst->Texture.Unit[i].CombineModeRGB = src->Texture.Unit[i].CombineModeRGB;
-      dst->Texture.Unit[i].CombineModeA = src->Texture.Unit[i].CombineModeA;
-      COPY_3V(dst->Texture.Unit[i].CombineSourceRGB, src->Texture.Unit[i].CombineSourceRGB);
-      COPY_3V(dst->Texture.Unit[i].CombineSourceA, src->Texture.Unit[i].CombineSourceA);
-      COPY_3V(dst->Texture.Unit[i].CombineOperandRGB, src->Texture.Unit[i].CombineOperandRGB);
-      COPY_3V(dst->Texture.Unit[i].CombineOperandA, src->Texture.Unit[i].CombineOperandA);
-      dst->Texture.Unit[i].CombineScaleShiftRGB = src->Texture.Unit[i].CombineScaleShiftRGB;
-      dst->Texture.Unit[i].CombineScaleShiftA = src->Texture.Unit[i].CombineScaleShiftA;
+      dst->Texture.Unit[i].Combine.ModeRGB = src->Texture.Unit[i].Combine.ModeRGB;
+      dst->Texture.Unit[i].Combine.ModeA = src->Texture.Unit[i].Combine.ModeA;
+      COPY_3V(dst->Texture.Unit[i].Combine.SourceRGB, src->Texture.Unit[i].Combine.SourceRGB);
+      COPY_3V(dst->Texture.Unit[i].Combine.SourceA, src->Texture.Unit[i].Combine.SourceA);
+      COPY_3V(dst->Texture.Unit[i].Combine.OperandRGB, src->Texture.Unit[i].Combine.OperandRGB);
+      COPY_3V(dst->Texture.Unit[i].Combine.OperandA, src->Texture.Unit[i].Combine.OperandA);
+      dst->Texture.Unit[i].Combine.ScaleShiftRGB = src->Texture.Unit[i].Combine.ScaleShiftRGB;
+      dst->Texture.Unit[i].Combine.ScaleShiftA = src->Texture.Unit[i].Combine.ScaleShiftA;
 
       /* texture object state */
       _mesa_copy_texture_object(dst->Texture.Unit[i].Current1D,
@@ -125,22 +144,22 @@ _mesa_print_texunit_state( GLcontext *ctx, GLuint unit )
    const struct gl_texture_unit *texUnit = ctx->Texture.Unit + unit;
    _mesa_printf("Texture Unit %d\n", unit);
    _mesa_printf("  GL_TEXTURE_ENV_MODE = %s\n", _mesa_lookup_enum_by_nr(texUnit->EnvMode));
-   _mesa_printf("  GL_COMBINE_RGB = %s\n", _mesa_lookup_enum_by_nr(texUnit->CombineModeRGB));
-   _mesa_printf("  GL_COMBINE_ALPHA = %s\n", _mesa_lookup_enum_by_nr(texUnit->CombineModeA));
-   _mesa_printf("  GL_SOURCE0_RGB = %s\n", _mesa_lookup_enum_by_nr(texUnit->CombineSourceRGB[0]));
-   _mesa_printf("  GL_SOURCE1_RGB = %s\n", _mesa_lookup_enum_by_nr(texUnit->CombineSourceRGB[1]));
-   _mesa_printf("  GL_SOURCE2_RGB = %s\n", _mesa_lookup_enum_by_nr(texUnit->CombineSourceRGB[2]));
-   _mesa_printf("  GL_SOURCE0_ALPHA = %s\n", _mesa_lookup_enum_by_nr(texUnit->CombineSourceA[0]));
-   _mesa_printf("  GL_SOURCE1_ALPHA = %s\n", _mesa_lookup_enum_by_nr(texUnit->CombineSourceA[1]));
-   _mesa_printf("  GL_SOURCE2_ALPHA = %s\n", _mesa_lookup_enum_by_nr(texUnit->CombineSourceA[2]));
-   _mesa_printf("  GL_OPERAND0_RGB = %s\n", _mesa_lookup_enum_by_nr(texUnit->CombineOperandRGB[0]));
-   _mesa_printf("  GL_OPERAND1_RGB = %s\n", _mesa_lookup_enum_by_nr(texUnit->CombineOperandRGB[1]));
-   _mesa_printf("  GL_OPERAND2_RGB = %s\n", _mesa_lookup_enum_by_nr(texUnit->CombineOperandRGB[2]));
-   _mesa_printf("  GL_OPERAND0_ALPHA = %s\n", _mesa_lookup_enum_by_nr(texUnit->CombineOperandA[0]));
-   _mesa_printf("  GL_OPERAND1_ALPHA = %s\n", _mesa_lookup_enum_by_nr(texUnit->CombineOperandA[1]));
-   _mesa_printf("  GL_OPERAND2_ALPHA = %s\n", _mesa_lookup_enum_by_nr(texUnit->CombineOperandA[2]));
-   _mesa_printf("  GL_RGB_SCALE = %d\n", 1 << texUnit->CombineScaleShiftRGB);
-   _mesa_printf("  GL_ALPHA_SCALE = %d\n", 1 << texUnit->CombineScaleShiftA);
+   _mesa_printf("  GL_COMBINE_RGB = %s\n", _mesa_lookup_enum_by_nr(texUnit->Combine.ModeRGB));
+   _mesa_printf("  GL_COMBINE_ALPHA = %s\n", _mesa_lookup_enum_by_nr(texUnit->Combine.ModeA));
+   _mesa_printf("  GL_SOURCE0_RGB = %s\n", _mesa_lookup_enum_by_nr(texUnit->Combine.SourceRGB[0]));
+   _mesa_printf("  GL_SOURCE1_RGB = %s\n", _mesa_lookup_enum_by_nr(texUnit->Combine.SourceRGB[1]));
+   _mesa_printf("  GL_SOURCE2_RGB = %s\n", _mesa_lookup_enum_by_nr(texUnit->Combine.SourceRGB[2]));
+   _mesa_printf("  GL_SOURCE0_ALPHA = %s\n", _mesa_lookup_enum_by_nr(texUnit->Combine.SourceA[0]));
+   _mesa_printf("  GL_SOURCE1_ALPHA = %s\n", _mesa_lookup_enum_by_nr(texUnit->Combine.SourceA[1]));
+   _mesa_printf("  GL_SOURCE2_ALPHA = %s\n", _mesa_lookup_enum_by_nr(texUnit->Combine.SourceA[2]));
+   _mesa_printf("  GL_OPERAND0_RGB = %s\n", _mesa_lookup_enum_by_nr(texUnit->Combine.OperandRGB[0]));
+   _mesa_printf("  GL_OPERAND1_RGB = %s\n", _mesa_lookup_enum_by_nr(texUnit->Combine.OperandRGB[1]));
+   _mesa_printf("  GL_OPERAND2_RGB = %s\n", _mesa_lookup_enum_by_nr(texUnit->Combine.OperandRGB[2]));
+   _mesa_printf("  GL_OPERAND0_ALPHA = %s\n", _mesa_lookup_enum_by_nr(texUnit->Combine.OperandA[0]));
+   _mesa_printf("  GL_OPERAND1_ALPHA = %s\n", _mesa_lookup_enum_by_nr(texUnit->Combine.OperandA[1]));
+   _mesa_printf("  GL_OPERAND2_ALPHA = %s\n", _mesa_lookup_enum_by_nr(texUnit->Combine.OperandA[2]));
+   _mesa_printf("  GL_RGB_SCALE = %d\n", 1 << texUnit->Combine.ScaleShiftRGB);
+   _mesa_printf("  GL_ALPHA_SCALE = %d\n", 1 << texUnit->Combine.ScaleShiftA);
    _mesa_printf("  GL_TEXTURE_ENV_COLOR = (%f, %f, %f, %f)\n", texUnit->EnvColor[0], texUnit->EnvColor[1], texUnit->EnvColor[2], texUnit->EnvColor[3]);
 }
 
@@ -150,6 +169,125 @@ _mesa_print_texunit_state( GLcontext *ctx, GLuint unit )
 /*                       Texture Environment                          */
 /**********************************************************************/
 
+/**
+ * Convert "classic" texture environment to ARB_texture_env_combine style
+ * environments.
+ * 
+ * \param state  texture_env_combine state vector to be filled-in.
+ * \param mode   Classic texture environment mode (i.e., \c GL_REPLACE,
+ *               \c GL_BLEND, \c GL_DECAL, etc.).
+ * \param tex_base_format  Base format of the texture associated with the
+ *               texture unit.
+ */
+static void
+calculate_derived_texenv( struct gl_tex_env_combine_state * state,
+			  GLenum mode, GLenum tex_base_format )
+{
+   GLenum mode_rgb;
+   GLenum mode_a;
+
+   *state = default_combine_state;
+
+   switch( tex_base_format ) {
+   case GL_ALPHA:
+      state->SourceRGB[0] = GL_PREVIOUS;
+      break;
+
+   case GL_LUMINANCE_ALPHA:
+   case GL_INTENSITY:
+   case GL_RGBA:
+      break;
+
+   case GL_LUMINANCE:
+   case GL_RGB:
+   case GL_YCBCR_MESA:
+      state->SourceA[0] = GL_PREVIOUS;
+      break;
+      
+   default:
+      state->SourceRGB[0] = GL_PREVIOUS;
+      state->SourceA[0]   = GL_PREVIOUS;
+      state->ModeRGB      = GL_REPLACE;
+      state->ModeA        = GL_REPLACE;
+      ASSERT(0);
+      return;
+   }
+
+   switch( mode ) {
+   case GL_REPLACE:
+   case GL_MODULATE:
+      mode_rgb = (tex_base_format == GL_ALPHA) ? GL_REPLACE : mode;
+      mode_a   = mode;
+      break;
+   
+   case GL_DECAL:
+      mode_rgb = GL_INTERPOLATE;
+      mode_a   = GL_REPLACE;
+
+      state->SourceA[0] = GL_PREVIOUS;
+
+      /* Having alpha / luminance / intensity textures replace using the
+       * incoming fragment color matches the definition in NV_texture_shader.
+       * The 1.5 spec simply marks these as "undefined".
+       */
+      switch( tex_base_format ) {
+      case GL_ALPHA:
+      case GL_LUMINANCE:
+      case GL_LUMINANCE_ALPHA:
+      case GL_INTENSITY:
+	 state->SourceRGB[0] = GL_PREVIOUS;
+	 break;
+      case GL_RGB:
+      case GL_YCBCR_MESA:
+	 mode_rgb = GL_REPLACE;
+	 break;
+      case GL_RGBA:
+	 state->SourceRGB[2] = GL_TEXTURE;
+	 break;
+      }
+      break;
+
+   case GL_BLEND:
+      mode_rgb = GL_INTERPOLATE;
+      mode_a   = GL_MODULATE;
+
+      switch( tex_base_format ) {
+      case GL_ALPHA:
+	 mode_rgb = GL_REPLACE;
+	 break;
+      case GL_INTENSITY:
+	 mode_a = GL_INTERPOLATE;
+	 /* FALLTHROUGH */
+      case GL_LUMINANCE:
+      case GL_RGB:
+      case GL_LUMINANCE_ALPHA:
+      case GL_RGBA:
+      case GL_YCBCR_MESA:
+	 state->SourceRGB[2] = GL_TEXTURE;
+	 state->SourceA[2]   = GL_TEXTURE;
+	 state->SourceRGB[0] = GL_CONSTANT;
+	 state->OperandRGB[2] = GL_SRC_COLOR;
+	 break;
+      }
+      break;
+
+   case GL_ADD:
+      mode_rgb = (tex_base_format == GL_ALPHA) ? GL_REPLACE : GL_ADD;
+      mode_a   = (tex_base_format == GL_INTENSITY) ? GL_ADD : GL_MODULATE;
+      break;
+
+   default:
+      mode_rgb = GL_REPLACE;
+      mode_a   = GL_REPLACE;
+      ASSERT(0);
+      break;
+   }
+   
+   state->ModeRGB = (state->SourceRGB[0] != GL_PREVIOUS)
+       ? mode_rgb : GL_REPLACE;
+   state->ModeA   = (state->SourceA[0]   != GL_PREVIOUS)
+       ? mode_a   : GL_REPLACE;
+}
 
 void GLAPIENTRY
 _mesa_TexEnvfv( GLenum target, GLenum pname, const GLfloat *param )
@@ -179,6 +317,18 @@ _mesa_TexEnvfv( GLenum target, GLenum pname, const GLfloat *param )
                   return;
                FLUSH_VERTICES(ctx, _NEW_TEXTURE);
                texUnit->EnvMode = mode;
+
+	       /* FIXME: Is this needed here or is having it in
+		* FIXME: update_texture_state enough?
+		*/
+	       if ( mode == GL_COMBINE ) {
+		  texUnit->_CurrentCombine = & texUnit->Combine;
+	       }
+	       else if ( texUnit->_Current != NULL ) {
+		  calculate_derived_texenv( & texUnit->_EnvMode, mode,
+					     texUnit->_Current->Image[0][0]->Format );
+		  texUnit->_CurrentCombine = & texUnit->_EnvMode;
+	       }
             }
             else {
                TE_ERROR(GL_INVALID_ENUM, "glTexEnv(param=%s)", mode);
@@ -243,10 +393,10 @@ _mesa_TexEnvfv( GLenum target, GLenum pname, const GLfloat *param )
                TE_ERROR(GL_INVALID_ENUM, "glTexEnv(param=%s)", mode);
 	       return;
 	    }
-	    if (texUnit->CombineModeRGB == mode)
+	    if (texUnit->Combine.ModeRGB == mode)
 	       return;
 	    FLUSH_VERTICES(ctx, _NEW_TEXTURE);
-	    texUnit->CombineModeRGB = mode;
+	    texUnit->Combine.ModeRGB = mode;
 	 }
 	 else {
             TE_ERROR(GL_INVALID_ENUM, "glTexEnv(pname=%s)", pname);
@@ -284,10 +434,10 @@ _mesa_TexEnvfv( GLenum target, GLenum pname, const GLfloat *param )
 	       return;
 	    }
 
-	    if (texUnit->CombineModeA == mode)
+	    if (texUnit->Combine.ModeA == mode)
 		return;
 	    FLUSH_VERTICES(ctx, _NEW_TEXTURE);
-	    texUnit->CombineModeA = mode;
+	    texUnit->Combine.ModeA = mode;
 	 }
 	 else {
             TE_ERROR(GL_INVALID_ENUM, "glTexEnv(pname=%s)", pname);
@@ -311,10 +461,10 @@ _mesa_TexEnvfv( GLenum target, GLenum pname, const GLfloat *param )
                 (ctx->Extensions.ATI_texture_env_combine3 &&
                  (source == GL_ZERO || source == GL_ONE))) {
                /* legal */
-               if (texUnit->CombineSourceRGB[s] == source)
+               if (texUnit->Combine.SourceRGB[s] == source)
                   return;
 	       FLUSH_VERTICES(ctx, _NEW_TEXTURE);
-	       texUnit->CombineSourceRGB[s] = source;
+	       texUnit->Combine.SourceRGB[s] = source;
             }
             else {
                TE_ERROR(GL_INVALID_ENUM, "glTexEnv(param=%s)", source);
@@ -343,10 +493,10 @@ _mesa_TexEnvfv( GLenum target, GLenum pname, const GLfloat *param )
 		(ctx->Extensions.ATI_texture_env_combine3 &&
                  (source == GL_ZERO || source == GL_ONE))) {
                /* legal */
-	       if (texUnit->CombineSourceA[s] == source)
+	       if (texUnit->Combine.SourceA[s] == source)
                   return;
 	       FLUSH_VERTICES(ctx, _NEW_TEXTURE);
-	       texUnit->CombineSourceA[s] = source;
+	       texUnit->Combine.SourceA[s] = source;
             }
             else {
                TE_ERROR(GL_INVALID_ENUM, "glTexEnv(param=%s)", source);
@@ -369,10 +519,10 @@ _mesa_TexEnvfv( GLenum target, GLenum pname, const GLfloat *param )
 	    case GL_ONE_MINUS_SRC_COLOR:
 	    case GL_SRC_ALPHA:
 	    case GL_ONE_MINUS_SRC_ALPHA:
-	       if (texUnit->CombineOperandRGB[s] == operand)
+	       if (texUnit->Combine.OperandRGB[s] == operand)
 		  return;
 	       FLUSH_VERTICES(ctx, _NEW_TEXTURE);
-	       texUnit->CombineOperandRGB[s] = operand;
+	       texUnit->Combine.OperandRGB[s] = operand;
 	       break;
 	    default:
                TE_ERROR(GL_INVALID_ENUM, "glTexEnv(param=%s)", operand);
@@ -392,11 +542,11 @@ _mesa_TexEnvfv( GLenum target, GLenum pname, const GLfloat *param )
 	    switch (operand) {
 	    case GL_SRC_ALPHA:
 	    case GL_ONE_MINUS_SRC_ALPHA:
-	       if (texUnit->CombineOperandA[pname-GL_OPERAND0_ALPHA] ==
+	       if (texUnit->Combine.OperandA[pname-GL_OPERAND0_ALPHA] ==
 		   operand)
 		  return;
 	       FLUSH_VERTICES(ctx, _NEW_TEXTURE);
-	       texUnit->CombineOperandA[pname-GL_OPERAND0_ALPHA] = operand;
+	       texUnit->Combine.OperandA[pname-GL_OPERAND0_ALPHA] = operand;
 	       break;
 	    default:
                TE_ERROR(GL_INVALID_ENUM, "glTexEnv(param=%s)", operand);
@@ -417,10 +567,10 @@ _mesa_TexEnvfv( GLenum target, GLenum pname, const GLfloat *param )
 	    case GL_ONE_MINUS_SRC_COLOR: /* ARB combine only */
 	    case GL_SRC_ALPHA:
 	    case GL_ONE_MINUS_SRC_ALPHA: /* ARB combine only */
-	       if (texUnit->CombineOperandRGB[2] == operand)
+	       if (texUnit->Combine.OperandRGB[2] == operand)
 		  return;
 	       FLUSH_VERTICES(ctx, _NEW_TEXTURE);
-	       texUnit->CombineOperandRGB[2] = operand;
+	       texUnit->Combine.OperandRGB[2] = operand;
                break;
 	    default:
                TE_ERROR(GL_INVALID_ENUM, "glTexEnv(param=%s)", operand);
@@ -439,10 +589,10 @@ _mesa_TexEnvfv( GLenum target, GLenum pname, const GLfloat *param )
 	    switch (operand) {
 	    case GL_SRC_ALPHA:
 	    case GL_ONE_MINUS_SRC_ALPHA: /* ARB combine only */
-	       if (texUnit->CombineOperandA[2] == operand)
+	       if (texUnit->Combine.OperandA[2] == operand)
 		  return;
 	       FLUSH_VERTICES(ctx, _NEW_TEXTURE);
-	       texUnit->CombineOperandA[2] = operand;
+	       texUnit->Combine.OperandA[2] = operand;
 	       break;
 	    default:
                TE_ERROR(GL_INVALID_ENUM, "glTexEnv(param=%s)", operand);
@@ -472,10 +622,10 @@ _mesa_TexEnvfv( GLenum target, GLenum pname, const GLfloat *param )
                             "glTexEnv(GL_RGB_SCALE not 1, 2 or 4)" );
 	       return;
 	    }
-	    if (texUnit->CombineScaleShiftRGB == newshift)
+	    if (texUnit->Combine.ScaleShiftRGB == newshift)
 	       return;
 	    FLUSH_VERTICES(ctx, _NEW_TEXTURE);
-	    texUnit->CombineScaleShiftRGB = newshift;
+	    texUnit->Combine.ScaleShiftRGB = newshift;
 	 }
 	 else {
             TE_ERROR(GL_INVALID_ENUM, "glTexEnv(pname=%s)", pname);
@@ -500,10 +650,10 @@ _mesa_TexEnvfv( GLenum target, GLenum pname, const GLfloat *param )
                             "glTexEnv(GL_ALPHA_SCALE not 1, 2 or 4)" );
 	       return;
 	    }
-	    if (texUnit->CombineScaleShiftA == newshift)
+	    if (texUnit->Combine.ScaleShiftA == newshift)
 	       return;
 	    FLUSH_VERTICES(ctx, _NEW_TEXTURE);
-	    texUnit->CombineScaleShiftA = newshift;
+	    texUnit->Combine.ScaleShiftA = newshift;
 	 }
 	 else {
             TE_ERROR(GL_INVALID_ENUM, "glTexEnv(pname=%s)", pname);
@@ -634,7 +784,7 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_COMBINE_RGB:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLfloat) texUnit->CombineModeRGB;
+               *params = (GLfloat) texUnit->Combine.ModeRGB;
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnvfv(pname)");
@@ -643,7 +793,7 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_COMBINE_ALPHA:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLfloat) texUnit->CombineModeA;
+               *params = (GLfloat) texUnit->Combine.ModeA;
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnvfv(pname)");
@@ -652,7 +802,7 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_SOURCE0_RGB:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLfloat) texUnit->CombineSourceRGB[0];
+               *params = (GLfloat) texUnit->Combine.SourceRGB[0];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnvfv(pname)");
@@ -661,7 +811,7 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_SOURCE1_RGB:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLfloat) texUnit->CombineSourceRGB[1];
+               *params = (GLfloat) texUnit->Combine.SourceRGB[1];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnvfv(pname)");
@@ -670,7 +820,7 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_SOURCE2_RGB:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLfloat) texUnit->CombineSourceRGB[2];
+               *params = (GLfloat) texUnit->Combine.SourceRGB[2];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnvfv(pname)");
@@ -679,7 +829,7 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_SOURCE0_ALPHA:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLfloat) texUnit->CombineSourceA[0];
+               *params = (GLfloat) texUnit->Combine.SourceA[0];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnvfv(pname)");
@@ -688,7 +838,7 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_SOURCE1_ALPHA:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLfloat) texUnit->CombineSourceA[1];
+               *params = (GLfloat) texUnit->Combine.SourceA[1];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnvfv(pname)");
@@ -697,7 +847,7 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_SOURCE2_ALPHA:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLfloat) texUnit->CombineSourceA[2];
+               *params = (GLfloat) texUnit->Combine.SourceA[2];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnvfv(pname)");
@@ -706,7 +856,7 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_OPERAND0_RGB:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLfloat) texUnit->CombineOperandRGB[0];
+               *params = (GLfloat) texUnit->Combine.OperandRGB[0];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnvfv(pname)");
@@ -715,7 +865,7 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_OPERAND1_RGB:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLfloat) texUnit->CombineOperandRGB[1];
+               *params = (GLfloat) texUnit->Combine.OperandRGB[1];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnvfv(pname)");
@@ -724,7 +874,7 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_OPERAND2_RGB:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLfloat) texUnit->CombineOperandRGB[2];
+               *params = (GLfloat) texUnit->Combine.OperandRGB[2];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnvfv(pname)");
@@ -733,7 +883,7 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_OPERAND0_ALPHA:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLfloat) texUnit->CombineOperandA[0];
+               *params = (GLfloat) texUnit->Combine.OperandA[0];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnvfv(pname)");
@@ -742,7 +892,7 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_OPERAND1_ALPHA:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLfloat) texUnit->CombineOperandA[1];
+               *params = (GLfloat) texUnit->Combine.OperandA[1];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnvfv(pname)");
@@ -751,7 +901,7 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_OPERAND2_ALPHA:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLfloat) texUnit->CombineOperandA[2];
+               *params = (GLfloat) texUnit->Combine.OperandA[2];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnvfv(pname)");
@@ -760,9 +910,9 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_RGB_SCALE:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               if (texUnit->CombineScaleShiftRGB == 0)
+               if (texUnit->Combine.ScaleShiftRGB == 0)
                   *params = 1.0;
-               else if (texUnit->CombineScaleShiftRGB == 1)
+               else if (texUnit->Combine.ScaleShiftRGB == 1)
                   *params = 2.0;
                else
                   *params = 4.0;
@@ -775,9 +925,9 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
          case GL_ALPHA_SCALE:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               if (texUnit->CombineScaleShiftA == 0)
+               if (texUnit->Combine.ScaleShiftA == 0)
                   *params = 1.0;
-               else if (texUnit->CombineScaleShiftA == 1)
+               else if (texUnit->Combine.ScaleShiftA == 1)
                   *params = 2.0;
                else
                   *params = 4.0;
@@ -848,7 +998,7 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_COMBINE_RGB:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLint) texUnit->CombineModeRGB;
+               *params = (GLint) texUnit->Combine.ModeRGB;
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnviv(pname)");
@@ -857,7 +1007,7 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_COMBINE_ALPHA:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLint) texUnit->CombineModeA;
+               *params = (GLint) texUnit->Combine.ModeA;
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnviv(pname)");
@@ -866,7 +1016,7 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_SOURCE0_RGB:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLint) texUnit->CombineSourceRGB[0];
+               *params = (GLint) texUnit->Combine.SourceRGB[0];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnviv(pname)");
@@ -875,7 +1025,7 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_SOURCE1_RGB:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLint) texUnit->CombineSourceRGB[1];
+               *params = (GLint) texUnit->Combine.SourceRGB[1];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnviv(pname)");
@@ -884,7 +1034,7 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_SOURCE2_RGB:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLint) texUnit->CombineSourceRGB[2];
+               *params = (GLint) texUnit->Combine.SourceRGB[2];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnviv(pname)");
@@ -893,7 +1043,7 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_SOURCE0_ALPHA:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLint) texUnit->CombineSourceA[0];
+               *params = (GLint) texUnit->Combine.SourceA[0];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnviv(pname)");
@@ -902,7 +1052,7 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_SOURCE1_ALPHA:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLint) texUnit->CombineSourceA[1];
+               *params = (GLint) texUnit->Combine.SourceA[1];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnviv(pname)");
@@ -911,7 +1061,7 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_SOURCE2_ALPHA:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLint) texUnit->CombineSourceA[2];
+               *params = (GLint) texUnit->Combine.SourceA[2];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnviv(pname)");
@@ -920,7 +1070,7 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_OPERAND0_RGB:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLint) texUnit->CombineOperandRGB[0];
+               *params = (GLint) texUnit->Combine.OperandRGB[0];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnviv(pname)");
@@ -929,7 +1079,7 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_OPERAND1_RGB:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLint) texUnit->CombineOperandRGB[1];
+               *params = (GLint) texUnit->Combine.OperandRGB[1];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnviv(pname)");
@@ -938,7 +1088,7 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_OPERAND2_RGB:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLint) texUnit->CombineOperandRGB[2];
+               *params = (GLint) texUnit->Combine.OperandRGB[2];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnviv(pname)");
@@ -947,7 +1097,7 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_OPERAND0_ALPHA:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLint) texUnit->CombineOperandA[0];
+               *params = (GLint) texUnit->Combine.OperandA[0];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnviv(pname)");
@@ -956,7 +1106,7 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_OPERAND1_ALPHA:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLint) texUnit->CombineOperandA[1];
+               *params = (GLint) texUnit->Combine.OperandA[1];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnviv(pname)");
@@ -965,7 +1115,7 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_OPERAND2_ALPHA:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               *params = (GLint) texUnit->CombineOperandA[2];
+               *params = (GLint) texUnit->Combine.OperandA[2];
             }
             else {
                _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexEnviv(pname)");
@@ -974,9 +1124,9 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_RGB_SCALE:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               if (texUnit->CombineScaleShiftRGB == 0)
+               if (texUnit->Combine.ScaleShiftRGB == 0)
                   *params = 1;
-               else if (texUnit->CombineScaleShiftRGB == 1)
+               else if (texUnit->Combine.ScaleShiftRGB == 1)
                   *params = 2;
                else
                   *params = 4;
@@ -989,9 +1139,9 @@ _mesa_GetTexEnviv( GLenum target, GLenum pname, GLint *params )
          case GL_ALPHA_SCALE:
             if (ctx->Extensions.EXT_texture_env_combine ||
                 ctx->Extensions.ARB_texture_env_combine) {
-               if (texUnit->CombineScaleShiftA == 0)
+               if (texUnit->Combine.ScaleShiftA == 0)
                   *params = 1;
-               else if (texUnit->CombineScaleShiftA == 1)
+               else if (texUnit->Combine.ScaleShiftA == 1)
                   *params = 2;
                else
                   *params = 4;
@@ -2800,6 +2950,64 @@ update_texture_state( GLcontext *ctx )
       if (texUnit->_ReallyEnabled)
          ctx->Texture._EnabledUnits |= (1 << unit);
 
+      if ( texUnit->EnvMode == GL_COMBINE ) {
+	 texUnit->_CurrentCombine = & texUnit->Combine;
+      }
+      else {
+	 calculate_derived_texenv( & texUnit->_EnvMode, 
+				    texUnit->EnvMode,
+				    texUnit->_Current->Image[0][0]->Format );
+	 texUnit->_CurrentCombine = & texUnit->_EnvMode;
+      }
+
+      switch (texUnit->_CurrentCombine->ModeRGB) {
+      case GL_REPLACE:
+	 texUnit->_CurrentCombine->_NumArgsRGB = 1;
+	 break;
+      case GL_MODULATE:
+      case GL_ADD:
+      case GL_ADD_SIGNED:
+      case GL_SUBTRACT:
+      case GL_DOT3_RGB:
+      case GL_DOT3_RGBA:
+      case GL_DOT3_RGB_EXT:
+      case GL_DOT3_RGBA_EXT:
+	 texUnit->_CurrentCombine->_NumArgsRGB = 2;
+	 break;
+      case GL_INTERPOLATE:
+      case GL_MODULATE_ADD_ATI:
+      case GL_MODULATE_SIGNED_ADD_ATI:
+      case GL_MODULATE_SUBTRACT_ATI:
+	 texUnit->_CurrentCombine->_NumArgsRGB = 3;
+	 break;
+      default:
+	 texUnit->_CurrentCombine->_NumArgsRGB = 0;
+	 ASSERT(0);
+	 break;
+      }
+
+      switch (texUnit->_CurrentCombine->ModeA) {
+      case GL_REPLACE:
+	 texUnit->_CurrentCombine->_NumArgsA = 1;
+	 break;
+      case GL_MODULATE:
+      case GL_ADD:
+      case GL_ADD_SIGNED:
+      case GL_SUBTRACT:
+	 texUnit->_CurrentCombine->_NumArgsA = 2;
+	 break;
+      case GL_INTERPOLATE:
+      case GL_MODULATE_ADD_ATI:
+      case GL_MODULATE_SIGNED_ADD_ATI:
+      case GL_MODULATE_SUBTRACT_ATI:
+	 texUnit->_CurrentCombine->_NumArgsA = 3;
+	 break;
+      default:
+	 texUnit->_CurrentCombine->_NumArgsA = 0;
+	 ASSERT(0);
+	 break;
+      }
+
       if (texUnit->TexGenEnabled) {
 	 if (texUnit->TexGenEnabled & S_BIT) {
 	    texUnit->_GenFlags |= texUnit->_GenBitS;
@@ -2910,22 +3118,9 @@ init_texture_unit( GLcontext *ctx, GLuint unit )
    texUnit->EnvMode = GL_MODULATE;
    ASSIGN_4V( texUnit->EnvColor, 0.0, 0.0, 0.0, 0.0 );
 
-   texUnit->CombineModeRGB = GL_MODULATE;
-   texUnit->CombineModeA = GL_MODULATE;
-   texUnit->CombineSourceRGB[0] = GL_TEXTURE;
-   texUnit->CombineSourceRGB[1] = GL_PREVIOUS_EXT;
-   texUnit->CombineSourceRGB[2] = GL_CONSTANT_EXT;
-   texUnit->CombineSourceA[0] = GL_TEXTURE;
-   texUnit->CombineSourceA[1] = GL_PREVIOUS_EXT;
-   texUnit->CombineSourceA[2] = GL_CONSTANT_EXT;
-   texUnit->CombineOperandRGB[0] = GL_SRC_COLOR;
-   texUnit->CombineOperandRGB[1] = GL_SRC_COLOR;
-   texUnit->CombineOperandRGB[2] = GL_SRC_ALPHA;
-   texUnit->CombineOperandA[0] = GL_SRC_ALPHA;
-   texUnit->CombineOperandA[1] = GL_SRC_ALPHA;
-   texUnit->CombineOperandA[2] = GL_SRC_ALPHA;
-   texUnit->CombineScaleShiftRGB = 0;
-   texUnit->CombineScaleShiftA = 0;
+   texUnit->Combine = default_combine_state;
+   texUnit->_EnvMode = default_combine_state;
+   texUnit->_CurrentCombine = & texUnit->_EnvMode;
 
    texUnit->TexGenEnabled = 0;
    texUnit->GenModeS = GL_EYE_LINEAR;