s_texcombine.c

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

/*
 * Mesa 3-D graphics library
 * Version:  6.5.1
 *
 * Copyright (C) 1999-2006  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 "imports.h"
#include "macros.h"
#include "pixel.h"

#include "s_context.h"
#include "s_texcombine.h"


#define PROD(A,B)   ( (GLuint)(A) * ((GLuint)(B)+1) )
#define S_PROD(A,B) ( (GLint)(A) * ((GLint)(B)+1) )
#if CHAN_BITS == 32
typedef GLfloat ChanTemp;
#else
typedef GLuint ChanTemp;
#endif


/**
 * Do texture application for GL_ARB/EXT_texture_env_combine.
 * This function also supports GL_{EXT,ARB}_texture_env_dot3 and
 * GL_ATI_texture_env_combine3.  Since "classic" texture environments are
 * implemented using GL_ARB_texture_env_combine-like state, this same function
 * is used for classic texture environment application as well.
 *
 * \param ctx          rendering context
 * \param textureUnit  the texture unit to apply
 * \param n            number of fragments to process (span width)
 * \param primary_rgba incoming fragment color array
 * \param texelBuffer  pointer to texel colors for all texture units
 * 
 * \param rgba         incoming colors, which get modified here
 */
static void
texture_combine( const GLcontext *ctx, GLuint unit, GLuint n,
                 CONST GLchan (*primary_rgba)[4],
                 CONST GLchan *texelBuffer,
                 GLchan (*rgba)[4] )
{
   const struct gl_texture_unit *textureUnit = &(ctx->Texture.Unit[unit]);
   const GLchan (*argRGB [3])[4];
   const GLchan (*argA [3])[4];
   const GLuint RGBshift = textureUnit->_CurrentCombine->ScaleShiftRGB;
   const GLuint Ashift   = textureUnit->_CurrentCombine->ScaleShiftA;
#if CHAN_TYPE == GL_FLOAT
   const GLchan RGBmult = (GLfloat) (1 << RGBshift);
   const GLchan Amult = (GLfloat) (1 << Ashift);
#else
   const GLint half = (CHAN_MAX + 1) / 2;
#endif
   static const GLchan one[4] = { CHAN_MAX, CHAN_MAX, CHAN_MAX, CHAN_MAX };
   static const GLchan zero[4] = { 0, 0, 0, 0 };
   const GLuint numColorArgs = textureUnit->_CurrentCombine->_NumArgsRGB;
   const GLuint numAlphaArgs = textureUnit->_CurrentCombine->_NumArgsA;
   GLchan ccolor[3][MAX_WIDTH][4];
   GLuint i, j;

   ASSERT(ctx->Extensions.EXT_texture_env_combine ||
          ctx->Extensions.ARB_texture_env_combine);
   ASSERT(SWRAST_CONTEXT(ctx)->_AnyTextureCombine);

   /*
   printf("modeRGB 0x%x  modeA 0x%x  srcRGB1 0x%x  srcA1 0x%x  srcRGB2 0x%x  srcA2 0x%x\n",
          textureUnit->_CurrentCombine->ModeRGB,
          textureUnit->_CurrentCombine->ModeA,
          textureUnit->_CurrentCombine->SourceRGB[0],
          textureUnit->_CurrentCombine->SourceA[0],
          textureUnit->_CurrentCombine->SourceRGB[1],
          textureUnit->_CurrentCombine->SourceA[1]);
   */

   /*
    * Do operand setup for up to 3 operands.  Loop over the terms.
    */
   for (j = 0; j < numColorArgs; j++) {
      const GLenum srcRGB = textureUnit->_CurrentCombine->SourceRGB[j];

      switch (srcRGB) {
         case GL_TEXTURE:
            argRGB[j] = (const GLchan (*)[4])
               (texelBuffer + unit * (n * 4 * sizeof(GLchan)));
            break;
         case GL_PRIMARY_COLOR:
            argRGB[j] = primary_rgba;
            break;
         case GL_PREVIOUS:
            argRGB[j] = (const GLchan (*)[4]) rgba;
            break;
         case GL_CONSTANT:
            {
               GLchan (*c)[4] = ccolor[j];
               GLchan red, green, blue, alpha;
               UNCLAMPED_FLOAT_TO_CHAN(red,   textureUnit->EnvColor[0]);
               UNCLAMPED_FLOAT_TO_CHAN(green, textureUnit->EnvColor[1]);
               UNCLAMPED_FLOAT_TO_CHAN(blue,  textureUnit->EnvColor[2]);
               UNCLAMPED_FLOAT_TO_CHAN(alpha, textureUnit->EnvColor[3]);
               for (i = 0; i < n; i++) {
                  c[i][RCOMP] = red;
                  c[i][GCOMP] = green;
                  c[i][BCOMP] = blue;
                  c[i][ACOMP] = alpha;
               }
               argRGB[j] = (const GLchan (*)[4]) ccolor[j];
            }
            break;
	 /* GL_ATI_texture_env_combine3 allows GL_ZERO & GL_ONE as sources.
	  */
	 case GL_ZERO:
            argRGB[j] = & zero;
            break;
	 case GL_ONE:
            argRGB[j] = & one;
            break;
         default:
            /* ARB_texture_env_crossbar source */
            {
               const GLuint srcUnit = srcRGB - GL_TEXTURE0;
               ASSERT(srcUnit < ctx->Const.MaxTextureUnits);
               if (!ctx->Texture.Unit[srcUnit]._ReallyEnabled)
                  return;
               argRGB[j] = (const GLchan (*)[4])
                  (texelBuffer + srcUnit * (n * 4 * sizeof(GLchan)));
            }
      }

      if (textureUnit->_CurrentCombine->OperandRGB[j] != GL_SRC_COLOR) {
         const GLchan (*src)[4] = argRGB[j];
         GLchan (*dst)[4] = ccolor[j];

         /* point to new arg[j] storage */
         argRGB[j] = (const GLchan (*)[4]) ccolor[j];

         if (textureUnit->_CurrentCombine->OperandRGB[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->_CurrentCombine->OperandRGB[j] == GL_SRC_ALPHA) {
            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 {
            ASSERT(textureUnit->_CurrentCombine->OperandRGB[j] ==GL_ONE_MINUS_SRC_ALPHA);
            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];
            }
         }
      }
   }

   /*
    * Set up the argA[i] pointers
    */
   for (j = 0; j < numAlphaArgs; j++) {
      const GLenum srcA = textureUnit->_CurrentCombine->SourceA[j];

      switch (srcA) {
         case GL_TEXTURE:
            argA[j] = (const GLchan (*)[4])
               (texelBuffer + unit * (n * 4 * sizeof(GLchan)));
            break;
         case GL_PRIMARY_COLOR:
            argA[j] = primary_rgba;
            break;
         case GL_PREVIOUS:
            argA[j] = (const GLchan (*)[4]) rgba;
            break;
         case GL_CONSTANT:
            {
               GLchan alpha, (*c)[4] = ccolor[j];
               UNCLAMPED_FLOAT_TO_CHAN(alpha, textureUnit->EnvColor[3]);
               for (i = 0; i < n; i++)
                  c[i][ACOMP] = alpha;
               argA[j] = (const GLchan (*)[4]) ccolor[j];
            }
            break;
	 /* GL_ATI_texture_env_combine3 allows GL_ZERO & GL_ONE as sources.
	  */
	 case GL_ZERO:
            argA[j] = & zero;
            break;
	 case GL_ONE:
            argA[j] = & one;
            break;
         default:
            /* ARB_texture_env_crossbar source */
            {
               const GLuint srcUnit = srcA - GL_TEXTURE0;
               ASSERT(srcUnit < ctx->Const.MaxTextureUnits);
               if (!ctx->Texture.Unit[srcUnit]._ReallyEnabled)
                  return;
               argA[j] = (const GLchan (*)[4])
                  (texelBuffer + srcUnit * (n * 4 * sizeof(GLchan)));
            }
      }

      if (textureUnit->_CurrentCombine->OperandA[j] == GL_ONE_MINUS_SRC_ALPHA) {
         const GLchan (*src)[4] = argA[j];
         GLchan (*dst)[4] = ccolor[j];
         argA[j] = (const GLchan (*)[4]) ccolor[j];
         for (i = 0; i < n; i++) {
            dst[i][ACOMP] = CHAN_MAX - src[i][ACOMP];
         }
      }
   }

   /*
    * Do the texture combine.
    */
   switch (textureUnit->_CurrentCombine->ModeRGB) {
      case GL_REPLACE:
         {
            const GLchan (*arg0)[4] = (const GLchan (*)[4]) argRGB[0];
            if (RGBshift) {
               for (i = 0; i < n; i++) {
#if CHAN_TYPE == GL_FLOAT
                  rgba[i][RCOMP] = arg0[i][RCOMP] * RGBmult;
                  rgba[i][GCOMP] = arg0[i][GCOMP] * RGBmult;
                  rgba[i][BCOMP] = arg0[i][BCOMP] * RGBmult;
#else
                  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);
#endif
               }
            }
            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];
#if CHAN_TYPE != GL_FLOAT
            const GLint shift = CHAN_BITS - RGBshift;
#endif
            for (i = 0; i < n; i++) {
#if CHAN_TYPE == GL_FLOAT
               rgba[i][RCOMP] = arg0[i][RCOMP] * arg1[i][RCOMP] * RGBmult;
               rgba[i][GCOMP] = arg0[i][GCOMP] * arg1[i][GCOMP] * RGBmult;
               rgba[i][BCOMP] = arg0[i][BCOMP] * arg1[i][BCOMP] * RGBmult;
#else
               GLuint r = PROD(arg0[i][RCOMP], arg1[i][RCOMP]) >> shift;
               GLuint g = PROD(arg0[i][GCOMP], arg1[i][GCOMP]) >> shift;
               GLuint b = PROD(arg0[i][BCOMP], 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);
#endif
            }
         }
         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++) {
#if CHAN_TYPE == GL_FLOAT
               rgba[i][RCOMP] = (arg0[i][RCOMP] + arg1[i][RCOMP]) * RGBmult;
               rgba[i][GCOMP] = (arg0[i][GCOMP] + arg1[i][GCOMP]) * RGBmult;
               rgba[i][BCOMP] = (arg0[i][BCOMP] + arg1[i][BCOMP]) * RGBmult;
#else
               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);
#endif
            }
         }
         break;
      case GL_ADD_SIGNED:
         {
            const GLchan (*arg0)[4] = (const GLchan (*)[4]) argRGB[0];
            const GLchan (*arg1)[4] = (const GLchan (*)[4]) argRGB[1];
            for (i = 0; i < n; i++) {
#if CHAN_TYPE == GL_FLOAT
               rgba[i][RCOMP] = (arg0[i][RCOMP] + arg1[i][RCOMP] - 0.5) * RGBmult;
               rgba[i][GCOMP] = (arg0[i][GCOMP] + arg1[i][GCOMP] - 0.5) * RGBmult;
               rgba[i][BCOMP] = (arg0[i][BCOMP] + arg1[i][BCOMP] - 0.5) * RGBmult;
#else
               GLint r = (GLint) arg0[i][RCOMP] + (GLint) arg1[i][RCOMP] -half;
               GLint g = (GLint) arg0[i][GCOMP] + (GLint) arg1[i][GCOMP] -half;
               GLint b = (GLint) arg0[i][BCOMP] + (GLint) arg1[i][BCOMP] -half;
               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);
#endif
            }
         }
         break;
      case GL_INTERPOLATE:
         {
            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];
#if CHAN_TYPE != GL_FLOAT
            const GLint shift = CHAN_BITS - RGBshift;
#endif
            for (i = 0; i < n; i++) {
#if CHAN_TYPE == GL_FLOAT
               rgba[i][RCOMP] = (arg0[i][RCOMP] * arg2[i][RCOMP] +
                      arg1[i][RCOMP] * (CHAN_MAXF - arg2[i][RCOMP])) * RGBmult;
               rgba[i][GCOMP] = (arg0[i][GCOMP] * arg2[i][GCOMP] +
                      arg1[i][GCOMP] * (CHAN_MAXF - arg2[i][GCOMP])) * RGBmult;
               rgba[i][BCOMP] = (arg0[i][BCOMP] * arg2[i][BCOMP] +
                      arg1[i][BCOMP] * (CHAN_MAXF - arg2[i][BCOMP])) * RGBmult;
#else
               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);
#endif
            }
         }
         break;
      case GL_SUBTRACT:
         {
            const GLchan (*arg0)[4] = (const GLchan (*)[4]) argRGB[0];
            const GLchan (*arg1)[4] = (const GLchan (*)[4]) argRGB[1];
            for (i = 0; i < n; i++) {
#if CHAN_TYPE == GL_FLOAT
               rgba[i][RCOMP] = (arg0[i][RCOMP] - arg1[i][RCOMP]) * RGBmult;
               rgba[i][GCOMP] = (arg0[i][GCOMP] - arg1[i][GCOMP]) * RGBmult;
               rgba[i][BCOMP] = (arg0[i][BCOMP] - arg1[i][BCOMP]) * RGBmult;
#else
               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) CLAMP(r, 0, CHAN_MAX);
               rgba[i][GCOMP] = (GLchan) CLAMP(g, 0, CHAN_MAX);
               rgba[i][BCOMP] = (GLchan) CLAMP(b, 0, CHAN_MAX);
#endif
            }
         }
         break;