s_texcombine.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

	       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:
               _mesa_problem(ctx, "Bad format (GL_REPLACE) in texture_apply");
               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:
               _mesa_problem(ctx, "Bad format (GL_MODULATE) in texture_apply");
               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 */
		  GLchan 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:
               _mesa_problem(ctx, "Bad format (GL_DECAL) in texture_apply");
               return;
	 }
	 break;

      case GL_BLEND:
         UNCLAMPED_FLOAT_TO_CHAN(Rc, texUnit->EnvColor[0]);
         UNCLAMPED_FLOAT_TO_CHAN(Gc, texUnit->EnvColor[1]);
         UNCLAMPED_FLOAT_TO_CHAN(Bc, texUnit->EnvColor[2]);
         UNCLAMPED_FLOAT_TO_CHAN(Ac, texUnit->EnvColor[3]);
	 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) + CcIt */
		  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:
               _mesa_problem(ctx, "Bad format (GL_BLEND) in texture_apply");
               return;
	 }
	 break;

     /* XXX don't clamp results if GLchan is float??? */

      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++) {
                  ChanTemp Lt = texel[i][RCOMP];
                  ChanTemp r = rgba[i][RCOMP] + Lt;
                  ChanTemp g = rgba[i][GCOMP] + Lt;
                  ChanTemp 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++) {
                  ChanTemp Lt = texel[i][RCOMP];
                  ChanTemp r = rgba[i][RCOMP] + Lt;
                  ChanTemp g = rgba[i][GCOMP] + Lt;
                  ChanTemp 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];
                  ChanTemp r = rgba[i][RCOMP] + It;
                  ChanTemp g = rgba[i][GCOMP] + It;
                  ChanTemp b = rgba[i][BCOMP] + It;
                  ChanTemp 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++) {
                  ChanTemp r = rgba[i][RCOMP] + texel[i][RCOMP];
                  ChanTemp g = rgba[i][GCOMP] + texel[i][GCOMP];
                  ChanTemp 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++) {
                  ChanTemp r = rgba[i][RCOMP] + texel[i][RCOMP];
                  ChanTemp g = rgba[i][GCOMP] + texel[i][GCOMP];
                  ChanTemp 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:
               _mesa_problem(ctx, "Bad format (GL_ADD) in texture_apply");
               return;
	 }
	 break;

      default:
         _mesa_problem(ctx, "Bad env mode in texture_apply");
         return;
   }
}



/**
 * Apply texture mapping to a span of fragments.
 */
void
_swrast_texture_span( GLcontext *ctx, SWspan *span )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);
   GLchan primary_rgba[MAX_WIDTH][4];
   GLuint unit;

   ASSERT(span->end < MAX_WIDTH);

   /*
    * Save copy of the incoming fragment colors (the GL_PRIMARY_COLOR)
    */
   if (swrast->_AnyTextureCombine)
      MEMCPY(primary_rgba, span->array->rgba, 4 * span->end * sizeof(GLchan));

   /*
    * Must do all texture sampling before combining in order to
    * accomodate GL_ARB_texture_env_crossbar.
    */
   for (unit = 0; unit < ctx->Const.MaxTextureUnits; unit++) {
      if (ctx->Texture.Unit[unit]._ReallyEnabled) {
         const GLfloat (*texcoords)[4]
            = (const GLfloat (*)[4])
            span->array->attribs[FRAG_ATTRIB_TEX0 + unit];
         const struct gl_texture_unit *texUnit = &ctx->Texture.Unit[unit];
         const struct gl_texture_object *curObj = texUnit->_Current;
         GLfloat *lambda = span->array->lambda[unit];
         GLchan (*texels)[4] = (GLchan (*)[4])
            (swrast->TexelBuffer + unit * (span->end * 4 * sizeof(GLchan)));

         /* adjust texture lod (lambda) */
         if (span->arrayMask & SPAN_LAMBDA) {
            if (texUnit->LodBias + curObj->LodBias != 0.0F) {
               /* apply LOD bias, but don't clamp yet */
               const GLfloat bias = CLAMP(texUnit->LodBias + curObj->LodBias,
                                          -ctx->Const.MaxTextureLodBias,
                                          ctx->Const.MaxTextureLodBias);
               GLuint i;
               for (i = 0; i < span->end; i++) {
                  lambda[i] += bias;
               }
            }

            if (curObj->MinLod != -1000.0 || curObj->MaxLod != 1000.0) {
               /* apply LOD clamping to lambda */
               const GLfloat min = curObj->MinLod;
               const GLfloat max = curObj->MaxLod;
               GLuint i;
               for (i = 0; i < span->end; i++) {
                  GLfloat l = lambda[i];
                  lambda[i] = CLAMP(l, min, max);
               }
            }
         }

         /* Sample the texture (span->end = number of fragments) */
         swrast->TextureSample[unit]( ctx, texUnit->_Current, span->end,
                                      texcoords, lambda, texels );

         /* GL_SGI_texture_color_table */
         if (texUnit->ColorTableEnabled) {
#if CHAN_TYPE == GL_UNSIGNED_BYTE
            _mesa_lookup_rgba_ubyte(&texUnit->ColorTable, span->end, texels);
#elif CHAN_TYPE == GL_UNSIGNED_SHORT
            _mesa_lookup_rgba_ubyte(&texUnit->ColorTable, span->end, texels);
#else
            _mesa_lookup_rgba_float(&texUnit->ColorTable, span->end, texels);
#endif
         }
      }
   }

   /*
    * OK, now apply the texture (aka texture combine/blend).
    * We modify the span->color.rgba values.
    */
   for (unit = 0; unit < ctx->Const.MaxTextureUnits; unit++) {
      if (ctx->Texture.Unit[unit]._ReallyEnabled) {
         const struct gl_texture_unit *texUnit = &ctx->Texture.Unit[unit];
         if (texUnit->_CurrentCombine != &texUnit->_EnvMode ) {
            texture_combine( ctx, unit, span->end,
                             (CONST GLchan (*)[4]) primary_rgba,
                             swrast->TexelBuffer,
                             span->array->rgba );
         }
         else {
            /* conventional texture blend */
            const GLchan (*texels)[4] = (const GLchan (*)[4])
               (swrast->TexelBuffer + unit *
                (span->end * 4 * sizeof(GLchan)));
            texture_apply( ctx, texUnit, span->end,
                           (CONST GLchan (*)[4]) primary_rgba, texels,
                           span->array->rgba );
         }
      }
   }
}