tile_alloc.comp raw

   1  // SPDX-License-Identifier: Apache-2.0 OR MIT OR Unlicense
   2  
   3  // Allocation and initialization of tiles for paths.
   4  
   5  #version 450
   6  #extension GL_GOOGLE_include_directive : enable
   7  
   8  #include "mem.h"
   9  #include "setup.h"
  10  
  11  #define LG_TILE_ALLOC_WG (7 + LG_WG_FACTOR)
  12  #define TILE_ALLOC_WG (1 << LG_TILE_ALLOC_WG)
  13  
  14  layout(local_size_x = TILE_ALLOC_WG, local_size_y = 1) in;
  15  
  16  layout(set = 0, binding = 1) readonly buffer ConfigBuf {
  17      Config conf;
  18  };
  19  
  20  #include "annotated.h"
  21  #include "tile.h"
  22  
  23  // scale factors useful for converting coordinates to tiles
  24  #define SX (1.0 / float(TILE_WIDTH_PX))
  25  #define SY (1.0 / float(TILE_HEIGHT_PX))
  26  
  27  shared uint sh_tile_count[TILE_ALLOC_WG];
  28  shared MallocResult sh_tile_alloc;
  29  
  30  void main() {
  31      uint th_ix = gl_LocalInvocationID.x;
  32      uint element_ix = gl_GlobalInvocationID.x;
  33      PathRef path_ref = PathRef(conf.tile_alloc.offset + element_ix * Path_size);
  34      AnnotatedRef ref = AnnotatedRef(conf.anno_alloc.offset + element_ix * Annotated_size);
  35  
  36      uint tag = Annotated_Nop;
  37      if (element_ix < conf.n_elements) {
  38          tag = Annotated_tag(conf.anno_alloc, ref).tag;
  39      }
  40      int x0 = 0, y0 = 0, x1 = 0, y1 = 0;
  41      switch (tag) {
  42      case Annotated_Color:
  43      case Annotated_Image:
  44      case Annotated_BeginClip:
  45      case Annotated_EndClip:
  46          // Note: we take advantage of the fact that fills, strokes, and
  47          // clips have compatible layout.
  48          AnnoEndClip clip = Annotated_EndClip_read(conf.anno_alloc, ref);
  49          x0 = int(floor(clip.bbox.x * SX));
  50          y0 = int(floor(clip.bbox.y * SY));
  51          x1 = int(ceil(clip.bbox.z * SX));
  52          y1 = int(ceil(clip.bbox.w * SY));
  53          break;
  54      }
  55      x0 = clamp(x0, 0, int(conf.width_in_tiles));
  56      y0 = clamp(y0, 0, int(conf.height_in_tiles));
  57      x1 = clamp(x1, 0, int(conf.width_in_tiles));
  58      y1 = clamp(y1, 0, int(conf.height_in_tiles));
  59  
  60      Path path;
  61      path.bbox = uvec4(x0, y0, x1, y1);
  62      uint tile_count = (x1 - x0) * (y1 - y0);
  63      if (tag == Annotated_EndClip) {
  64          // Don't actually allocate tiles for an end clip, but we do want
  65          // the path structure (especially bbox) allocated for it.
  66          tile_count = 0;
  67      }
  68  
  69      sh_tile_count[th_ix] = tile_count;
  70      uint total_tile_count = tile_count;
  71      // Prefix sum of sh_tile_count
  72      for (uint i = 0; i < LG_TILE_ALLOC_WG; i++) {
  73          barrier();
  74          if (th_ix >= (1 << i)) {
  75              total_tile_count += sh_tile_count[th_ix - (1 << i)];
  76          }
  77          barrier();
  78          sh_tile_count[th_ix] = total_tile_count;
  79      }
  80      if (th_ix == TILE_ALLOC_WG - 1) {
  81          sh_tile_alloc = malloc(total_tile_count * Tile_size);
  82      }
  83      barrier();
  84      MallocResult alloc_start = sh_tile_alloc;
  85      if (alloc_start.failed || mem_error != NO_ERROR) {
  86          return;
  87      }
  88  
  89      if (element_ix < conf.n_elements) {
  90          uint tile_subix = th_ix > 0 ? sh_tile_count[th_ix - 1] : 0;
  91          Alloc tiles_alloc = slice_mem(alloc_start.alloc, Tile_size * tile_subix, Tile_size * tile_count);
  92          path.tiles = TileRef(tiles_alloc.offset);
  93          Path_write(conf.tile_alloc, path_ref, path);
  94      }
  95  
  96      // Zero out allocated tiles efficiently
  97      uint total_count = sh_tile_count[TILE_ALLOC_WG - 1] * (Tile_size / 4);
  98      uint start_ix = alloc_start.alloc.offset >> 2;
  99      for (uint i = th_ix; i < total_count; i += TILE_ALLOC_WG) {
 100          // Note: this interleaving is faster than using Tile_write
 101          // by a significant amount.
 102          write_mem(alloc_start.alloc, start_ix + i, 0);
 103      }
 104  }
 105