src/gallium/drivers/llvmpipe/lp_rast_tri.c

   1 /**************************************************************************
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   3  * Copyright 2007-2009 VMware, Inc.
   4  * All Rights Reserved.
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   7  * copy of this software and associated documentation files (the
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  11  * permit persons to whom the Software is furnished to do so, subject to
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  13  *
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  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
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  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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  27
  28 /*
  29  * Rasterization for binned triangles within a tile
  30  */
  31
  32 #include <limits.h>
  33 #include "util/u_math.h"
  34 #include "lp_debug.h"
  35 #include "lp_rast_priv.h"
  36 #include "lp_tile_soa.h"
  37
  38
  39 /**
  40  * Map an index in [0,15] to an x,y position, multiplied by 4.
  41  * This is used to get the position of each subtile in a 4x4
  42  * grid of edge step values.
  43  */
  44 static const int pos_table4[16][2] = {
  45    { 0, 0 },
  46    { 4, 0 },
  47    { 0, 4 },
  48    { 4, 4 },
  49    { 8, 0 },
  50    { 12, 0 },
  51    { 8, 4 },
  52    { 12, 4 },
  53    { 0, 8 },
  54    { 4, 8 },
  55    { 0, 12 },
  56    { 4, 12 },
  57    { 8, 8 },
  58    { 12, 8 },
  59    { 8, 12 },
  60    { 12, 12 }
  61 };
  62
  63
  64 static const int pos_table16[16][2] = {
  65    { 0, 0 },
  66    { 16, 0 },
  67    { 0, 16 },
  68    { 16, 16 },
  69    { 32, 0 },
  70    { 48, 0 },
  71    { 32, 16 },
  72    { 48, 16 },
  73    { 0, 32 },
  74    { 16, 32 },
  75    { 0, 48 },
  76    { 16, 48 },
  77    { 32, 32 },
  78    { 48, 32 },
  79    { 32, 48 },
  80    { 48, 48 }
  81 };
  82
  83
  84 /**
  85  * Shade all pixels in a 4x4 block.
  86  */
  87 static void
  88 block_full_4( struct lp_rasterizer_task *rast_task,
  89               const struct lp_rast_triangle *tri,
  90               int x, int y )
  91 {
  92    lp_rast_shade_quads_all(rast_task->rast,
  93                            rast_task->thread_index,
  94                            &tri->inputs,
  95                            x, y);
  96 }
  97
  98
  99 /**
 100  * Shade all pixels in a 16x16 block.
 101  */
 102 static void
 103 block_full_16( struct lp_rasterizer_task *rast_task,
 104                const struct lp_rast_triangle *tri,
 105                int x, int y )
 106 {
 107    unsigned ix, iy;
 108    assert(x % 16 == 0);
 109    assert(y % 16 == 0);
 110    for (iy = 0; iy < 16; iy += 4)
 111       for (ix = 0; ix < 16; ix += 4)
 112          block_full_4(rast_task, tri, x + ix, y + iy);
 113 }
 114
 115
 116 /**
 117  * Pass the 4x4 pixel block to the shader function.
 118  * Determination of which of the 16 pixels lies inside the triangle
 119  * will be done as part of the fragment shader.
 120  */
 121 static void
 122 do_block_4( struct lp_rasterizer_task *rast_task,
 123             const struct lp_rast_triangle *tri,
 124             int x, int y,
 125             int c1,
 126             int c2,
 127             int c3 )
 128 {
 129    lp_rast_shade_quads(rast_task->rast,
 130                        rast_task->thread_index,
 131                        &tri->inputs,
 132                        x, y,
 133                        -c1, -c2, -c3);
 134 }
 135
 136
 137 /**
 138  * Evaluate a 16x16 block of pixels to determine which 4x4 subblocks are in/out
 139  * of the triangle's bounds.
 140  */
 141 static void
 142 do_block_16( struct lp_rasterizer_task *rast_task,
 143              const struct lp_rast_triangle *tri,
 144              int x, int y,
 145              int c1,
 146              int c2,
 147              int c3 )
 148 {
 149    const int ei1 = tri->ei1 * 4;
 150    const int ei2 = tri->ei2 * 4;
 151    const int ei3 = tri->ei3 * 4;
 152
 153    const int eo1 = tri->eo1 * 4;
 154    const int eo2 = tri->eo2 * 4;
 155    const int eo3 = tri->eo3 * 4;
 156
 157    int i;
 158
 159    assert(x % 16 == 0);
 160    assert(y % 16 == 0);
 161
 162    for (i = 0; i < 16; i++) {
 163       int cx1 = c1 + (tri->inputs.step[0][i] * 4);
 164       int cx2 = c2 + (tri->inputs.step[1][i] * 4);
 165       int cx3 = c3 + (tri->inputs.step[2][i] * 4);
 166
 167       if (cx1 + eo1 < 0 ||
 168           cx2 + eo2 < 0 ||
 169           cx3 + eo3 < 0) {
 170          /* the block is completely outside the triangle - nop */
 171       }
 172       else {
 173          int px = x + pos_table4[i][0];
 174          int py = y + pos_table4[i][1];
 175          if (cx1 + ei1 > 0 &&
 176              cx2 + ei2 > 0 &&
 177              cx3 + ei3 > 0) {
 178             /* the block is completely inside the triangle */
 179             block_full_4(rast_task, tri, px, py);
 180          }
 181          else {
 182             /* the block is partially in/out of the triangle */
 183             do_block_4(rast_task, tri, px, py, cx1, cx2, cx3);
 184          }
 185       }
 186    }
 187 }
 188
 189
 190 /**
 191  * Scan the tile in chunks and figure out which pixels to rasterize
 192  * for this triangle.
 193  */
 194 void
 195 lp_rast_triangle( struct lp_rasterizer *rast,
 196                   unsigned thread_index,
 197                   const union lp_rast_cmd_arg arg )
 198 {
 199    struct lp_rasterizer_task *rast_task = &rast->tasks[thread_index];
 200    const struct lp_rast_triangle *tri = arg.triangle;
 201
 202    int x = rast_task->x;
 203    int y = rast_task->y;
 204    unsigned i;
 205
 206    int c1 = tri->c1 + tri->dx12 * y - tri->dy12 * x;
 207    int c2 = tri->c2 + tri->dx23 * y - tri->dy23 * x;
 208    int c3 = tri->c3 + tri->dx31 * y - tri->dy31 * x;
 209
 210    int ei1 = tri->ei1 * 16;
 211    int ei2 = tri->ei2 * 16;
 212    int ei3 = tri->ei3 * 16;
 213
 214    int eo1 = tri->eo1 * 16;
 215    int eo2 = tri->eo2 * 16;
 216    int eo3 = tri->eo3 * 16;
 217
 218    LP_DBG(DEBUG_RAST, "lp_rast_triangle\n");
 219
 220    /* Walk over the tile to build a list of 4x4 pixel blocks which will
 221     * be filled/shaded.  We do this at two granularities: 16x16 blocks
 222     * and then 4x4 blocks.
 223     */
 224    for (i = 0; i < 16; i++) {
 225       int cx1 = c1 + (tri->inputs.step[0][i] * 16);
 226       int cx2 = c2 + (tri->inputs.step[1][i] * 16);
 227       int cx3 = c3 + (tri->inputs.step[2][i] * 16);
 228
 229       if (cx1 + eo1 < 0 ||
 230           cx2 + eo2 < 0 ||
 231           cx3 + eo3 < 0) {
 232          /* the block is completely outside the triangle - nop */
 233       }
 234       else {
 235          int px = x + pos_table16[i][0];
 236          int py = y + pos_table16[i][1];
 237
 238          if (cx1 + ei1 > 0 &&
 239              cx2 + ei2 > 0 &&
 240              cx3 + ei3 > 0) {
 241             /* the block is completely inside the triangle */
 242             block_full_16(rast_task, tri, px, py);
 243          }
 244          else {
 245             /* the block is partially in/out of the triangle */
 246             do_block_16(rast_task, tri, px, py, cx1, cx2, cx3);
 247          }
 248       }
 249    }
 250 }