src/gallium/drivers/softpipe/sp_quad_depth_test.c

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   3  * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
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  27
  28 /**
  29  * \brief  Quad depth testing
  30  */
  31
  32 #include "pipe/p_defines.h"
  33 #include "pipe/p_util.h"
  34 #include "sp_context.h"
  35 #include "sp_headers.h"
  36 #include "sp_surface.h"
  37 #include "sp_quad.h"
  38 #include "sp_tile_cache.h"
  39
  40
  41 /**
  42  * Do depth testing for a quad.
  43  * Not static since it's used by the stencil code.
  44  */
  45
  46 /*
  47  * To increase efficiency, we should probably have multiple versions
  48  * of this function that are specifically for Z16, Z32 and FP Z buffers.
  49  * Try to effectively do that with codegen...
  50  */
  51
  52 void
  53 sp_depth_test_quad(struct quad_stage *qs, struct quad_header *quad)
  54 {
  55    struct softpipe_context *softpipe = qs->softpipe;
  56    struct pipe_surface *ps = softpipe->framebuffer.zsbuf;
  57    const enum pipe_format format = ps->format;
  58    unsigned bzzzz[QUAD_SIZE];  /**< Z values fetched from depth buffer */
  59    unsigned qzzzz[QUAD_SIZE];  /**< Z values from the quad */
  60    unsigned zmask = 0;
  61    unsigned j;
  62    struct softpipe_cached_tile *tile
  63       = sp_get_cached_tile(softpipe, softpipe->zsbuf_cache, quad->x0, quad->y0);
  64
  65    assert(ps); /* shouldn't get here if there's no zbuffer */
  66
  67    /*
  68     * Convert quad's float depth values to int depth values (qzzzz).
  69     * If the Z buffer stores integer values, we _have_ to do the depth
  70     * compares with integers (not floats).  Otherwise, the float->int->float
  71     * conversion of Z values (which isn't an identity function) will cause
  72     * Z-fighting errors.
  73     *
  74     * Also, get the zbuffer values (bzzzz) from the cached tile.
  75     */
  76    switch (format) {
  77    case PIPE_FORMAT_Z16_UNORM:
  78       {
  79          float scale = 65535.0;
  80
  81          for (j = 0; j < QUAD_SIZE; j++) {
  82             qzzzz[j] = (unsigned) (quad->outputs.depth[j] * scale);
  83          }
  84
  85          for (j = 0; j < QUAD_SIZE; j++) {
  86             int x = quad->x0 % TILE_SIZE + (j & 1);
  87             int y = quad->y0 % TILE_SIZE + (j >> 1);
  88             bzzzz[j] = tile->data.depth16[y][x];
  89          }
  90       }
  91       break;
  92    case PIPE_FORMAT_Z32_UNORM:
  93       {
  94          double scale = (double) (uint) ~0UL;
  95
  96          for (j = 0; j < QUAD_SIZE; j++) {
  97             qzzzz[j] = (unsigned) (quad->outputs.depth[j] * scale);
  98          }
  99
 100          for (j = 0; j < QUAD_SIZE; j++) {
 101             int x = quad->x0 % TILE_SIZE + (j & 1);
 102             int y = quad->y0 % TILE_SIZE + (j >> 1);
 103             bzzzz[j] = tile->data.depth32[y][x];
 104          }
 105       }
 106       break;
 107    case PIPE_FORMAT_S8Z24_UNORM:
 108       {
 109          float scale = (float) ((1 << 24) - 1);
 110
 111          for (j = 0; j < QUAD_SIZE; j++) {
 112             qzzzz[j] = (unsigned) (quad->outputs.depth[j] * scale);
 113          }
 114
 115          for (j = 0; j < QUAD_SIZE; j++) {
 116             int x = quad->x0 % TILE_SIZE + (j & 1);
 117             int y = quad->y0 % TILE_SIZE + (j >> 1);
 118             bzzzz[j] = tile->data.depth32[y][x] & 0xffffff;
 119          }
 120       }
 121       break;
 122    case PIPE_FORMAT_Z24S8_UNORM:
 123       {
 124          float scale = (float) ((1 << 24) - 1);
 125
 126          for (j = 0; j < QUAD_SIZE; j++) {
 127             qzzzz[j] = (unsigned) (quad->outputs.depth[j] * scale);
 128          }
 129
 130          for (j = 0; j < QUAD_SIZE; j++) {
 131             int x = quad->x0 % TILE_SIZE + (j & 1);
 132             int y = quad->y0 % TILE_SIZE + (j >> 1);
 133             bzzzz[j] = tile->data.depth32[y][x] >> 8;
 134          }
 135       }
 136       break;
 137    default:
 138       assert(0);
 139    }
 140
 141    switch (softpipe->depth_stencil->depth.func) {
 142    case PIPE_FUNC_NEVER:
 143       /* zmask = 0 */
 144       break;
 145    case PIPE_FUNC_LESS:
 146       /* Note this is pretty much a single sse or cell instruction.
 147        * Like this:  quad->mask &= (quad->outputs.depth < zzzz);
 148        */
 149       for (j = 0; j < QUAD_SIZE; j++) {
 150          if (qzzzz[j] < bzzzz[j])
 151             zmask |= 1 << j;
 152       }
 153       break;
 154    case PIPE_FUNC_EQUAL:
 155       for (j = 0; j < QUAD_SIZE; j++) {
 156          if (qzzzz[j] == bzzzz[j])
 157             zmask |= 1 << j;
 158       }
 159       break;
 160    case PIPE_FUNC_LEQUAL:
 161       for (j = 0; j < QUAD_SIZE; j++) {
 162          if (qzzzz[j] <= bzzzz[j])
 163             zmask |= (1 << j);
 164       }
 165       break;
 166    case PIPE_FUNC_GREATER:
 167       for (j = 0; j < QUAD_SIZE; j++) {
 168          if (qzzzz[j] > bzzzz[j])
 169             zmask |= (1 << j);
 170       }
 171       break;
 172    case PIPE_FUNC_NOTEQUAL:
 173       for (j = 0; j < QUAD_SIZE; j++) {
 174          if (qzzzz[j] != bzzzz[j])
 175             zmask |= (1 << j);
 176       }
 177       break;
 178    case PIPE_FUNC_GEQUAL:
 179       for (j = 0; j < QUAD_SIZE; j++) {
 180          if (qzzzz[j] >= bzzzz[j])
 181             zmask |= (1 << j);
 182       }
 183       break;
 184    case PIPE_FUNC_ALWAYS:
 185       zmask = MASK_ALL;
 186       break;
 187    default:
 188       abort();
 189    }
 190
 191    quad->mask &= zmask;
 192
 193    if (softpipe->depth_stencil->depth.writemask) {
 194
 195       /* This is also efficient with sse / spe instructions:
 196        */
 197       for (j = 0; j < QUAD_SIZE; j++) {
 198          if (quad->mask & (1 << j)) {
 199             bzzzz[j] = qzzzz[j];
 200          }
 201       }
 202
 203       /* put updated Z values back into cached tile */
 204       switch (format) {
 205       case PIPE_FORMAT_Z16_UNORM:
 206          for (j = 0; j < QUAD_SIZE; j++) {
 207             int x = quad->x0 % TILE_SIZE + (j & 1);
 208             int y = quad->y0 % TILE_SIZE + (j >> 1);
 209             tile->data.depth16[y][x] = (ushort) bzzzz[j];
 210          }
 211          break;
 212       case PIPE_FORMAT_Z32_UNORM:
 213          for (j = 0; j < QUAD_SIZE; j++) {
 214             int x = quad->x0 % TILE_SIZE + (j & 1);
 215             int y = quad->y0 % TILE_SIZE + (j >> 1);
 216             tile->data.depth32[y][x] = bzzzz[j];
 217          }
 218          break;
 219       case PIPE_FORMAT_S8Z24_UNORM:
 220          for (j = 0; j < QUAD_SIZE; j++) {
 221             int x = quad->x0 % TILE_SIZE + (j & 1);
 222             int y = quad->y0 % TILE_SIZE + (j >> 1);
 223             uint s8z24 = tile->data.depth32[y][x];
 224             s8z24 = (s8z24 & 0xff000000) | bzzzz[j];
 225             tile->data.depth32[y][x] = s8z24;
 226          }
 227          break;
 228       case PIPE_FORMAT_Z24S8_UNORM:
 229          for (j = 0; j < QUAD_SIZE; j++) {
 230             int x = quad->x0 % TILE_SIZE + (j & 1);
 231             int y = quad->y0 % TILE_SIZE + (j >> 1);
 232             uint z24s8 = tile->data.depth32[y][x];
 233             z24s8 = (z24s8 & 0xff) | (bzzzz[j] << 24);
 234             tile->data.depth32[y][x] = z24s8;
 235          }
 236          break;
 237       default:
 238          assert(0);
 239       }
 240    }
 241 }
 242
 243
 244 static void
 245 depth_test_quad(struct quad_stage *qs, struct quad_header *quad)
 246 {
 247    sp_depth_test_quad(qs, quad);
 248
 249    if (quad->mask)
 250       qs->next->run(qs->next, quad);
 251 }
 252
 253
 254 static void depth_test_begin(struct quad_stage *qs)
 255 {
 256    qs->next->begin(qs->next);
 257 }
 258
 259
 260 static void depth_test_destroy(struct quad_stage *qs)
 261 {
 262    FREE( qs );
 263 }
 264
 265
 266 struct quad_stage *sp_quad_depth_test_stage( struct softpipe_context *softpipe )
 267 {
 268    struct quad_stage *stage = CALLOC_STRUCT(quad_stage);
 269
 270    stage->softpipe = softpipe;
 271    stage->begin = depth_test_begin;
 272    stage->run = depth_test_quad;
 273    stage->destroy = depth_test_destroy;
 274
 275    return stage;
 276 }