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_const.h"
  75 #include "lp_bld_arit.h"
  76 #include "lp_bld_blend.h"
  77
  78
  79 /**
  80  * We may the same values several times, so we keep them here to avoid
  81  * recomputing them. Also reusing the values allows us to do simplifications
  82  * that LLVM optimization passes wouldn't normally be able to do.
  83  */
  84 struct lp_build_blend_soa_context
  85 {
  86    struct lp_build_context base;
  87
  88    LLVMValueRef src[4];
  89    LLVMValueRef dst[4];
  90    LLVMValueRef con[4];
  91
  92    LLVMValueRef inv_src[4];
  93    LLVMValueRef inv_dst[4];
  94    LLVMValueRef inv_con[4];
  95
  96    LLVMValueRef src_alpha_saturate;
  97
  98    /**
  99     * We store all factors in a table in order to eliminate redundant
 100     * multiplications later.
 101     */
 102    LLVMValueRef factor[2][2][4];
 103
 104    /**
 105     * Table with all terms.
 106     */
 107    LLVMValueRef term[2][4];
 108 };
 109
 110
 111 static LLVMValueRef
 112 lp_build_blend_soa_factor(struct lp_build_blend_soa_context *bld,
 113                           unsigned factor, unsigned i)
 114 {
 115    /*
 116     * Compute src/first term RGB
 117     */
 118    switch (factor) {
 119    case PIPE_BLENDFACTOR_ONE:
 120       return bld->base.one;
 121    case PIPE_BLENDFACTOR_SRC_COLOR:
 122       return bld->src[i];
 123    case PIPE_BLENDFACTOR_SRC_ALPHA:
 124       return bld->src[3];
 125    case PIPE_BLENDFACTOR_DST_COLOR:
 126       return bld->dst[i];
 127    case PIPE_BLENDFACTOR_DST_ALPHA:
 128       return bld->dst[3];
 129    case PIPE_BLENDFACTOR_SRC_ALPHA_SATURATE:
 130       if(i == 3)
 131          return bld->base.one;
 132       else {
 133          if(!bld->inv_dst[3])
 134             bld->inv_dst[3] = lp_build_comp(&bld->base, bld->dst[3]);
 135          if(!bld->src_alpha_saturate)
 136             bld->src_alpha_saturate = lp_build_min(&bld->base, bld->src[3], bld->inv_dst[3]);
 137          return bld->src_alpha_saturate;
 138       }
 139    case PIPE_BLENDFACTOR_CONST_COLOR:
 140       return bld->con[i];
 141    case PIPE_BLENDFACTOR_CONST_ALPHA:
 142       return bld->con[3];
 143    case PIPE_BLENDFACTOR_SRC1_COLOR:
 144       /* TODO */
 145       assert(0);
 146       return bld->base.zero;
 147    case PIPE_BLENDFACTOR_SRC1_ALPHA:
 148       /* TODO */
 149       assert(0);
 150       return bld->base.zero;
 151    case PIPE_BLENDFACTOR_ZERO:
 152       return bld->base.zero;
 153    case PIPE_BLENDFACTOR_INV_SRC_COLOR:
 154       if(!bld->inv_src[i])
 155          bld->inv_src[i] = lp_build_comp(&bld->base, bld->src[i]);
 156       return bld->inv_src[i];
 157    case PIPE_BLENDFACTOR_INV_SRC_ALPHA:
 158       if(!bld->inv_src[3])
 159          bld->inv_src[3] = lp_build_comp(&bld->base, bld->src[3]);
 160       return bld->inv_src[3];
 161    case PIPE_BLENDFACTOR_INV_DST_COLOR:
 162       if(!bld->inv_dst[i])
 163          bld->inv_dst[i] = lp_build_comp(&bld->base, bld->dst[i]);
 164       return bld->inv_dst[i];
 165    case PIPE_BLENDFACTOR_INV_DST_ALPHA:
 166       if(!bld->inv_dst[3])
 167          bld->inv_dst[3] = lp_build_comp(&bld->base, bld->dst[3]);
 168       return bld->inv_dst[3];
 169    case PIPE_BLENDFACTOR_INV_CONST_COLOR:
 170       if(!bld->inv_con[i])
 171          bld->inv_con[i] = lp_build_comp(&bld->base, bld->con[i]);
 172       return bld->inv_con[i];
 173    case PIPE_BLENDFACTOR_INV_CONST_ALPHA:
 174       if(!bld->inv_con[3])
 175          bld->inv_con[3] = lp_build_comp(&bld->base, bld->con[3]);
 176       return bld->inv_con[3];
 177    case PIPE_BLENDFACTOR_INV_SRC1_COLOR:
 178       /* TODO */
 179       assert(0);
 180       return bld->base.zero;
 181    case PIPE_BLENDFACTOR_INV_SRC1_ALPHA:
 182       /* TODO */
 183       assert(0);
 184       return bld->base.zero;
 185    default:
 186       assert(0);
 187       return bld->base.zero;
 188    }
 189 }
 190
 191
 192 /**
 193  * Generate blend code in SOA mode.
 194  * \param src  src/fragment color
 195  * \param dst  dst/framebuffer color
 196  * \param con  constant blend color
 197  * \param res  the result/output
 198  */
 199 void
 200 lp_build_blend_soa(LLVMBuilderRef builder,
 201                    const struct pipe_blend_state *blend,
 202                    struct lp_type type,
 203                    LLVMValueRef src[4],
 204                    LLVMValueRef dst[4],
 205                    LLVMValueRef con[4],
 206                    LLVMValueRef res[4])
 207 {
 208    struct lp_build_blend_soa_context bld;
 209    unsigned i, j, k;
 210
 211    /* Setup build context */
 212    memset(&bld, 0, sizeof bld);
 213    lp_build_context_init(&bld.base, builder, type);
 214    for (i = 0; i < 4; ++i) {
 215       bld.src[i] = src[i];
 216       bld.dst[i] = dst[i];
 217       bld.con[i] = con[i];
 218    }
 219
 220    for (i = 0; i < 4; ++i) {
 221       if (blend->colormask & (1 << i)) {
 222          if (blend->logicop_enable) {
 223             if(!type.floating) {
 224                res[i] = lp_build_logicop(builder, blend->logicop_func, src[i], dst[i]);
 225             }
 226             else
 227                res[i] = dst[i];
 228          }
 229          else if (blend->blend_enable) {
 230             unsigned src_factor = i < 3 ? blend->rgb_src_factor : blend->alpha_src_factor;
 231             unsigned dst_factor = i < 3 ? blend->rgb_dst_factor : blend->alpha_dst_factor;
 232             unsigned func = i < 3 ? blend->rgb_func : blend->alpha_func;
 233             boolean func_commutative = lp_build_blend_func_commutative(func);
 234
 235             /* It makes no sense to blend unless values are normalized */
 236             assert(type.norm);
 237
 238             /*
 239              * Compute src/dst factors.
 240              */
 241
 242             bld.factor[0][0][i] = src[i];
 243             bld.factor[0][1][i] = lp_build_blend_soa_factor(&bld, src_factor, i);
 244             bld.factor[1][0][i] = dst[i];
 245             bld.factor[1][1][i] = lp_build_blend_soa_factor(&bld, dst_factor, i);
 246
 247             /*
 248              * Compute src/dst terms
 249              */
 250
 251             for(k = 0; k < 2; ++k) {
 252                /* See if this multiplication has been previously computed */
 253                for(j = 0; j < i; ++j) {
 254                   if((bld.factor[k][0][j] == bld.factor[k][0][i] &&
 255                       bld.factor[k][1][j] == bld.factor[k][1][i]) ||
 256                      (bld.factor[k][0][j] == bld.factor[k][1][i] &&
 257                       bld.factor[k][1][j] == bld.factor[k][0][i]))
 258                      break;
 259                }
 260
 261                if(j < i)
 262                   bld.term[k][i] = bld.term[k][j];
 263                else
 264                   bld.term[k][i] = lp_build_mul(&bld.base, bld.factor[k][0][i], bld.factor[k][1][i]);
 265             }
 266
 267             /*
 268              * Combine terms
 269              */
 270
 271             /* See if this function has been previously applied */
 272             for(j = 0; j < i; ++j) {
 273                unsigned prev_func = j < 3 ? blend->rgb_func : blend->alpha_func;
 274                unsigned func_reverse = lp_build_blend_func_reverse(func, prev_func);
 275
 276                if((!func_reverse &&
 277                    bld.term[0][j] == bld.term[0][i] &&
 278                    bld.term[1][j] == bld.term[1][i]) ||
 279                   ((func_commutative || func_reverse) &&
 280                    bld.term[0][j] == bld.term[1][i] &&
 281                    bld.term[1][j] == bld.term[0][i]))
 282                   break;
 283             }
 284
 285             if(j < i)
 286                res[i] = res[j];
 287             else
 288                res[i] = lp_build_blend_func(&bld.base, func, bld.term[0][i], bld.term[1][i]);
 289          }
 290          else {
 291             res[i] = src[i];
 292          }
 293       }
 294       else {
 295          res[i] = dst[i];
 296       }
 297    }
 298 }