src/gallium/drivers/llvmpipe/lp_bld_blend_soa.c

/**************************************************************************
 *
 * Copyright 2009 VMware, Inc.
 * All Rights Reserved.
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 * copy of this software and associated documentation files (the
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 * permit persons to whom the Software is furnished to do so, subject to
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 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
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 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
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/**
 * @file
 * Blend LLVM IR generation -- SoA.
 *
 * @author Jose Fonseca <jfonseca@vmware.com>
 */


#include "pipe/p_state.h"

#include "lp_bld_type.h"
#include "lp_bld_const.h"
#include "lp_bld_arit.h"
#include "lp_bld_blend.h"


/**
 * We may the same values several times, so we keep them here to avoid
 * recomputing them. Also reusing the values allows us to do simplifications
 * that LLVM optimization passes wouldn't normally be able to do.
 */
struct lp_build_blend_soa_context
{
   struct lp_build_context base;

   LLVMValueRef src[4];
   LLVMValueRef dst[4];
   LLVMValueRef con[4];

   LLVMValueRef inv_src[4];
   LLVMValueRef inv_dst[4];
   LLVMValueRef inv_con[4];

   LLVMValueRef src_alpha_saturate;

   /**
    * We store all factors in a table in order to eliminate redundant
    * multiplications later.
    */
   LLVMValueRef factor[2][2][4];

   /**
    * Table with all terms.
    */
   LLVMValueRef term[2][4];
};


static LLVMValueRef
lp_build_blend_soa_factor(struct lp_build_blend_soa_context *bld,
                          unsigned factor, unsigned i)
{
   /*
    * Compute src/first term RGB
    */
   switch (factor) {
   case PIPE_BLENDFACTOR_ONE:
      return bld->base.one;
   case PIPE_BLENDFACTOR_SRC_COLOR:
      return bld->src[i];
   case PIPE_BLENDFACTOR_SRC_ALPHA:
      return bld->src[3];
   case PIPE_BLENDFACTOR_DST_COLOR:
      return bld->dst[i];
   case PIPE_BLENDFACTOR_DST_ALPHA:
      return bld->dst[3];
   case PIPE_BLENDFACTOR_SRC_ALPHA_SATURATE:
      if(i == 3)
         return bld->base.one;
      else {
         if(!bld->inv_dst[3])
            bld->inv_dst[3] = lp_build_comp(&bld->base, bld->dst[3]);
         if(!bld->src_alpha_saturate)
            bld->src_alpha_saturate = lp_build_min(&bld->base, bld->src[3], bld->inv_dst[3]);
         return bld->src_alpha_saturate;
      }
   case PIPE_BLENDFACTOR_CONST_COLOR:
      return bld->con[i];
   case PIPE_BLENDFACTOR_CONST_ALPHA:
      return bld->con[3];
   case PIPE_BLENDFACTOR_SRC1_COLOR:
      /* TODO */
      assert(0);
      return bld->base.zero;
   case PIPE_BLENDFACTOR_SRC1_ALPHA:
      /* TODO */
      assert(0);
      return bld->base.zero;
   case PIPE_BLENDFACTOR_ZERO:
      return bld->base.zero;
   case PIPE_BLENDFACTOR_INV_SRC_COLOR:
      if(!bld->inv_src[i])
         bld->inv_src[i] = lp_build_comp(&bld->base, bld->src[i]);
      return bld->inv_src[i];
   case PIPE_BLENDFACTOR_INV_SRC_ALPHA:
      if(!bld->inv_src[3])
         bld->inv_src[3] = lp_build_comp(&bld->base, bld->src[3]);
      return bld->inv_src[3];
   case PIPE_BLENDFACTOR_INV_DST_COLOR:
      if(!bld->inv_dst[i])
         bld->inv_dst[i] = lp_build_comp(&bld->base, bld->dst[i]);
      return bld->inv_dst[i];
   case PIPE_BLENDFACTOR_INV_DST_ALPHA:
      if(!bld->inv_dst[3])
         bld->inv_dst[3] = lp_build_comp(&bld->base, bld->dst[3]);
      return bld->inv_dst[3];
   case PIPE_BLENDFACTOR_INV_CONST_COLOR:
      if(!bld->inv_con[i])
         bld->inv_con[i] = lp_build_comp(&bld->base, bld->con[i]);
      return bld->inv_con[i];
   case PIPE_BLENDFACTOR_INV_CONST_ALPHA:
      if(!bld->inv_con[3])
         bld->inv_con[3] = lp_build_comp(&bld->base, bld->con[3]);
      return bld->inv_con[3];
   case PIPE_BLENDFACTOR_INV_SRC1_COLOR:
      /* TODO */
      assert(0);
      return bld->base.zero;
   case PIPE_BLENDFACTOR_INV_SRC1_ALPHA:
      /* TODO */
      assert(0);
      return bld->base.zero;
   default:
      assert(0);
      return bld->base.zero;
   }
}


/**
 * Generate blend code in SOA mode.
 * \param src  src/fragment color
 * \param dst  dst/framebuffer color
 * \param con  constant blend color
 * \param res  the result/output
 */
void
lp_build_blend_soa(LLVMBuilderRef builder,
                   const struct pipe_blend_state *blend,
                   union lp_type type,
                   LLVMValueRef src[4],
                   LLVMValueRef dst[4],
                   LLVMValueRef con[4],
                   LLVMValueRef res[4])
{
   struct lp_build_blend_soa_context bld;
   unsigned i, j, k;

   /* Setup build context */
   memset(&bld, 0, sizeof bld);
   lp_build_context_init(&bld.base, builder, type);
   for (i = 0; i < 4; ++i) {
      bld.src[i] = src[i];
      bld.dst[i] = dst[i];
      bld.con[i] = con[i];
   }

   for (i = 0; i < 4; ++i) {
      if (blend->colormask & (1 << i)) {
         if (blend->logicop_enable) {
            if(!type.floating) {
               res[i] = lp_build_logicop(builder, blend->logicop_func, src[i], dst[i]);
            }
            else
               res[i] = dst[i];
         }
         else if (blend->blend_enable) {
            unsigned src_factor = i < 3 ? blend->rgb_src_factor : blend->alpha_src_factor;
            unsigned dst_factor = i < 3 ? blend->rgb_dst_factor : blend->alpha_dst_factor;
            unsigned func = i < 3 ? blend->rgb_func : blend->alpha_func;
            boolean func_commutative = lp_build_blend_func_commutative(func);

            /* It makes no sense to blend unless values are normalized */
            assert(type.norm);

            /*
             * Compute src/dst factors.
             */

            bld.factor[0][0][i] = src[i];
            bld.factor[0][1][i] = lp_build_blend_soa_factor(&bld, src_factor, i);
            bld.factor[1][0][i] = dst[i];
            bld.factor[1][1][i] = lp_build_blend_soa_factor(&bld, dst_factor, i);

            /*
             * Compute src/dst terms
             */

            for(k = 0; k < 2; ++k) {
               /* See if this multiplication has been previously computed */
               for(j = 0; j < i; ++j) {
                  if((bld.factor[k][0][j] == bld.factor[k][0][i] &&
                      bld.factor[k][1][j] == bld.factor[k][1][i]) ||
                     (bld.factor[k][0][j] == bld.factor[k][1][i] &&
                      bld.factor[k][1][j] == bld.factor[k][0][i]))
                     break;
               }

               if(j < i)
                  bld.term[k][i] = bld.term[k][j];
               else
                  bld.term[k][i] = lp_build_mul(&bld.base, bld.factor[k][0][i], bld.factor[k][1][i]);
            }

            /*
             * Combine terms
             */

            /* See if this function has been previously applied */
            for(j = 0; j < i; ++j) {
               unsigned prev_func = j < 3 ? blend->rgb_func : blend->alpha_func;
               unsigned func_reverse = lp_build_blend_func_reverse(func, prev_func);

               if((!func_reverse &&
                   bld.term[0][j] == bld.term[0][i] &&
                   bld.term[1][j] == bld.term[1][i]) ||
                  ((func_commutative || func_reverse) &&
                   bld.term[0][j] == bld.term[1][i] &&
                   bld.term[1][j] == bld.term[0][i]))
                  break;
            }

            if(j < i)
               res[i] = res[j];
            else
               res[i] = lp_build_blend_func(&bld.base, func, bld.term[0][i], bld.term[1][i]);
         }
         else {
            res[i] = src[i];
         }
      }
      else {
         res[i] = dst[i];
      }
   }
}