src/gallium/drivers/llvmpipe/lp_bld_blend_soa.c

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  27
  28
  29 /**
  30  * @file
  31  * Blend LLVM IR generation -- SoA layout.
  32  *
  33  * Blending in SoA is much faster than AoS, especially when separate rgb/alpha
  34  * factors/functions are used, since no channel masking/shuffling is necessary
  35  * and we can achieve the full throughput of the SIMD operations. Furthermore
  36  * the fragment shader output is also in SoA, so it fits nicely with the rest of
  37  * the fragment pipeline.
  38  *
  39  * The drawback is that to be displayed the color buffer needs to be in AoS
  40  * layout, so we need to tile/untile the color buffer before/after rendering.
  41  * A color buffer like
  42  *
  43  *  R11 G11 B11 A11 R12 G12 B12 A12  R13 G13 B13 A13 R14 G14 B14 A14  ...
  44  *  R21 G21 B21 A21 R22 G22 B22 A22  R23 G23 B23 A23 R24 G24 B24 A24  ...
  45  *
  46  *  R31 G31 B31 A31 R32 G32 B32 A32  R33 G33 B33 A33 R34 G34 B34 A34  ...
  47  *  R41 G41 B41 A41 R42 G42 B42 A42  R43 G43 B43 A43 R44 G44 B44 A44  ...
  48  *
  49  *  ... ... ... ... ... ... ... ...  ... ... ... ... ... ... ... ...  ...
  50  *
  51  * will actually be stored in memory as
  52  *
  53  *  R11 R12 R21 R22 R13 R14 R23 R24 ... G11 G12 G21 G22 G13 G14 G23 G24 ... B11 B12 B21 B22 B13 B14 B23 B24 ... A11 A12 A21 A22 A13 A14 A23 A24 ...
  54  *  R31 R32 R41 R42 R33 R34 R43 R44 ... G31 G32 G41 G42 G33 G34 G43 G44 ... B31 B32 B41 B42 B33 B34 B43 B44 ... A31 A32 A41 A42 A33 A34 A43 A44 ...
  55  *  ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...
  56  *
  57  * NOTE: Run lp_blend_test after any change to this file.
  58  *
  59  * You can also run lp_blend_test to obtain AoS vs SoA benchmarks. Invoking it
  60  * as:
  61  *
  62  *  lp_blend_test -o blend.tsv
  63  *
  64  * will generate a tab-seperated-file with the test results and performance
  65  * measurements.
  66  *
  67  * @author Jose Fonseca <jfonseca@vmware.com>
  68  */
  69
  70
  71 #include "pipe/p_state.h"
  72
  73 #include "lp_bld_type.h"
  74 #include "lp_bld_arit.h"
  75 #include "lp_bld_blend.h"
  76
  77
  78 /**
  79  * We may the same values several times, so we keep them here to avoid
  80  * recomputing them. Also reusing the values allows us to do simplifications
  81  * that LLVM optimization passes wouldn't normally be able to do.
  82  */
  83 struct lp_build_blend_soa_context
  84 {
  85    struct lp_build_context base;
  86
  87    LLVMValueRef src[4];
  88    LLVMValueRef dst[4];
  89    LLVMValueRef con[4];
  90
  91    LLVMValueRef inv_src[4];
  92    LLVMValueRef inv_dst[4];
  93    LLVMValueRef inv_con[4];
  94
  95    LLVMValueRef src_alpha_saturate;
  96
  97    /**
  98     * We store all factors in a table in order to eliminate redundant
  99     * multiplications later.
 100     */
 101    LLVMValueRef factor[2][2][4];
 102
 103    /**
 104     * Table with all terms.
 105     */
 106    LLVMValueRef term[2][4];
 107 };
 108
 109
 110 static LLVMValueRef
 111 lp_build_blend_soa_factor(struct lp_build_blend_soa_context *bld,
 112                           unsigned factor, unsigned i)
 113 {
 114    /*
 115     * Compute src/first term RGB
 116     */
 117    switch (factor) {
 118    case PIPE_BLENDFACTOR_ONE:
 119       return bld->base.one;
 120    case PIPE_BLENDFACTOR_SRC_COLOR:
 121       return bld->src[i];
 122    case PIPE_BLENDFACTOR_SRC_ALPHA:
 123       return bld->src[3];
 124    case PIPE_BLENDFACTOR_DST_COLOR:
 125       return bld->dst[i];
 126    case PIPE_BLENDFACTOR_DST_ALPHA:
 127       return bld->dst[3];
 128    case PIPE_BLENDFACTOR_SRC_ALPHA_SATURATE:
 129       if(i == 3)
 130          return bld->base.one;
 131       else {
 132          if(!bld->inv_dst[3])
 133             bld->inv_dst[3] = lp_build_comp(&bld->base, bld->dst[3]);
 134          if(!bld->src_alpha_saturate)
 135             bld->src_alpha_saturate = lp_build_min(&bld->base, bld->src[3], bld->inv_dst[3]);
 136          return bld->src_alpha_saturate;
 137       }
 138    case PIPE_BLENDFACTOR_CONST_COLOR:
 139       return bld->con[i];
 140    case PIPE_BLENDFACTOR_CONST_ALPHA:
 141       return bld->con[3];
 142    case PIPE_BLENDFACTOR_SRC1_COLOR:
 143       /* TODO */
 144       assert(0);
 145       return bld->base.zero;
 146    case PIPE_BLENDFACTOR_SRC1_ALPHA:
 147       /* TODO */
 148       assert(0);
 149       return bld->base.zero;
 150    case PIPE_BLENDFACTOR_ZERO:
 151       return bld->base.zero;
 152    case PIPE_BLENDFACTOR_INV_SRC_COLOR:
 153       if(!bld->inv_src[i])
 154          bld->inv_src[i] = lp_build_comp(&bld->base, bld->src[i]);
 155       return bld->inv_src[i];
 156    case PIPE_BLENDFACTOR_INV_SRC_ALPHA:
 157       if(!bld->inv_src[3])
 158          bld->inv_src[3] = lp_build_comp(&bld->base, bld->src[3]);
 159       return bld->inv_src[3];
 160    case PIPE_BLENDFACTOR_INV_DST_COLOR:
 161       if(!bld->inv_dst[i])
 162          bld->inv_dst[i] = lp_build_comp(&bld->base, bld->dst[i]);
 163       return bld->inv_dst[i];
 164    case PIPE_BLENDFACTOR_INV_DST_ALPHA:
 165       if(!bld->inv_dst[3])
 166          bld->inv_dst[3] = lp_build_comp(&bld->base, bld->dst[3]);
 167       return bld->inv_dst[3];
 168    case PIPE_BLENDFACTOR_INV_CONST_COLOR:
 169       if(!bld->inv_con[i])
 170          bld->inv_con[i] = lp_build_comp(&bld->base, bld->con[i]);
 171       return bld->inv_con[i];
 172    case PIPE_BLENDFACTOR_INV_CONST_ALPHA:
 173       if(!bld->inv_con[3])
 174          bld->inv_con[3] = lp_build_comp(&bld->base, bld->con[3]);
 175       return bld->inv_con[3];
 176    case PIPE_BLENDFACTOR_INV_SRC1_COLOR:
 177       /* TODO */
 178       assert(0);
 179       return bld->base.zero;
 180    case PIPE_BLENDFACTOR_INV_SRC1_ALPHA:
 181       /* TODO */
 182       assert(0);
 183       return bld->base.zero;
 184    default:
 185       assert(0);
 186       return bld->base.zero;
 187    }
 188 }
 189
 190
 191 /**
 192  * Generate blend code in SOA mode.
 193  * \param src  src/fragment color
 194  * \param dst  dst/framebuffer color
 195  * \param con  constant blend color
 196  * \param res  the result/output
 197  */
 198 void
 199 lp_build_blend_soa(LLVMBuilderRef builder,
 200                    const struct pipe_blend_state *blend,
 201                    struct lp_type type,
 202                    LLVMValueRef src[4],
 203                    LLVMValueRef dst[4],
 204                    LLVMValueRef con[4],
 205                    LLVMValueRef res[4])
 206 {
 207    struct lp_build_blend_soa_context bld;
 208    unsigned i, j, k;
 209
 210    /* Setup build context */
 211    memset(&bld, 0, sizeof bld);
 212    lp_build_context_init(&bld.base, builder, type);
 213    for (i = 0; i < 4; ++i) {
 214       bld.src[i] = src[i];
 215       bld.dst[i] = dst[i];
 216       bld.con[i] = con[i];
 217    }
 218
 219    for (i = 0; i < 4; ++i) {
 220       if (blend->rt[0].colormask & (1 << i)) {
 221          if (blend->logicop_enable) {
 222             if(!type.floating) {
 223                res[i] = lp_build_logicop(builder, blend->logicop_func, src[i], dst[i]);
 224             }
 225             else
 226                res[i] = dst[i];
 227          }
 228          else if (blend->rt[0].blend_enable) {
 229             unsigned src_factor = i < 3 ? blend->rt[0].rgb_src_factor : blend->rt[0].alpha_src_factor;
 230             unsigned dst_factor = i < 3 ? blend->rt[0].rgb_dst_factor : blend->rt[0].alpha_dst_factor;
 231             unsigned func = i < 3 ? blend->rt[0].rgb_func : blend->rt[0].alpha_func;
 232             boolean func_commutative = lp_build_blend_func_commutative(func);
 233
 234             /* It makes no sense to blend unless values are normalized */
 235             assert(type.norm);
 236
 237             /*
 238              * Compute src/dst factors.
 239              */
 240
 241             bld.factor[0][0][i] = src[i];
 242             bld.factor[0][1][i] = lp_build_blend_soa_factor(&bld, src_factor, i);
 243             bld.factor[1][0][i] = dst[i];
 244             bld.factor[1][1][i] = lp_build_blend_soa_factor(&bld, dst_factor, i);
 245
 246             /*
 247              * Compute src/dst terms
 248              */
 249
 250             for(k = 0; k < 2; ++k) {
 251                /* See if this multiplication has been previously computed */
 252                for(j = 0; j < i; ++j) {
 253                   if((bld.factor[k][0][j] == bld.factor[k][0][i] &&
 254                       bld.factor[k][1][j] == bld.factor[k][1][i]) ||
 255                      (bld.factor[k][0][j] == bld.factor[k][1][i] &&
 256                       bld.factor[k][1][j] == bld.factor[k][0][i]))
 257                      break;
 258                }
 259
 260                if(j < i)
 261                   bld.term[k][i] = bld.term[k][j];
 262                else
 263                   bld.term[k][i] = lp_build_mul(&bld.base, bld.factor[k][0][i], bld.factor[k][1][i]);
 264             }
 265
 266             /*
 267              * Combine terms
 268              */
 269
 270             /* See if this function has been previously applied */
 271             for(j = 0; j < i; ++j) {
 272                unsigned prev_func = j < 3 ? blend->rt[0].rgb_func : blend->rt[0].alpha_func;
 273                unsigned func_reverse = lp_build_blend_func_reverse(func, prev_func);
 274
 275                if((!func_reverse &&
 276                    bld.term[0][j] == bld.term[0][i] &&
 277                    bld.term[1][j] == bld.term[1][i]) ||
 278                   ((func_commutative || func_reverse) &&
 279                    bld.term[0][j] == bld.term[1][i] &&
 280                    bld.term[1][j] == bld.term[0][i]))
 281                   break;
 282             }
 283
 284             if(j < i)
 285                res[i] = res[j];
 286             else
 287                res[i] = lp_build_blend_func(&bld.base, func, bld.term[0][i], bld.term[1][i]);
 288          }
 289          else {
 290             res[i] = src[i];
 291          }
 292       }
 293       else {
 294          res[i] = dst[i];
 295       }
 296    }
 297 }