6eb11fbf71
Each 8×8-tile workgroup previously had all 64 threads walk the entire item list, re-reading every item from the SSBO 64× and running the per-pixel reject for items that never touch the tile — O(tiles × N) item loads dominated by SSBO traffic. The workgroup now streams the item list in chunks of 64: each thread loads one item, tests its AABB against the whole tile, and the survivors are compacted — in original buffer order — into shared memory. Every thread then runs the unchanged per-pixel accumulate over only those survivors. This drops SSBO traffic ~64× (each item read once per workgroup instead of once per pixel) and shrinks the inner loop to the items that actually overlap the tile. Draw order is preserved exactly: chunks run in array order and the in-chunk compaction is a stable in-order scan, so later items still overdraw earlier ones (no atomic-append nondeterminism). The inner loop body is byte-for-byte the original per-pixel logic, so output is pixel-identical — the cull only decides which items reach it. Threads no longer early-return so every thread reaches the workgroup barriers. Applied to ui-quads, ui-circles, ui-images and ui-text; shared helpers (uiTileBounds / uiAabbOverlapsTile) live in ui-shared.glsl. Resolves #46 Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
109 lines
3.8 KiB
GLSL
109 lines
3.8 KiB
GLSL
#version 460
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#extension GL_GOOGLE_include_directive : enable
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#include "ui-shared.glsl"
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// One workgroup per 8×8 screen tile. The workgroup cooperatively streams the
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// GlyphItem list in chunks of 64 (see ui-shared.glsl), culling each chunk
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// against the tile and compacting survivors — in buffer order — into shared
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// memory; every thread then accumulates over only those survivors.
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layout(push_constant) uniform PC {
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UIDispatchHeader hdr;
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uint fontTextureSlot;
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uint fontSamplerSlot;
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uint _p0;
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uint _p1;
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} pc;
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layout(local_size_x = 8, local_size_y = 8, local_size_z = 1) in;
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// SDF tuning — must match Crafter::FontAtlas::kOnEdgeValue / kPixelDistScale.
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const float ON_EDGE = 128.0 / 255.0;
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const float DIST_SCALE = 32.0;
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shared vec4 s_rect[UI_CHUNK];
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shared vec4 s_uv[UI_CHUNK];
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shared vec4 s_color[UI_CHUNK];
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shared uint s_keep[UI_CHUNK];
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shared uint s_order[UI_CHUNK];
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shared uint s_count;
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void main() {
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ivec2 screenPx;
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bool valid = uiResolveScreenPixel(pc.hdr, screenPx);
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vec4 dst = vec4(0.0);
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vec2 sp = vec2(0.0);
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if (valid) {
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dst = imageLoad(uiImages[pc.hdr.outImage], screenPx);
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sp = vec2(screenPx) + 0.5;
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}
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vec2 tileMin, tileMax;
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uiTileBounds(tileMin, tileMax);
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uint lid = gl_LocalInvocationIndex;
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for (uint base = 0u; base < pc.hdr.itemCount; base += UI_CHUNK) {
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uint idx = base + lid;
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bool keep = false;
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if (idx < pc.hdr.itemCount) {
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s_rect[lid] = uiGlyphHeap[pc.hdr.itemBuffer].items[idx].rect;
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s_uv[lid] = uiGlyphHeap[pc.hdr.itemBuffer].items[idx].uv;
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s_color[lid] = uiGlyphHeap[pc.hdr.itemBuffer].items[idx].color;
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keep = uiAabbOverlapsTile(s_rect[lid].xy, s_rect[lid].xy + s_rect[lid].zw,
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tileMin, tileMax);
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}
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s_keep[lid] = keep ? 1u : 0u;
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barrier();
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if (lid == 0u) {
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uint n = 0u;
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uint lim = min(UI_CHUNK, pc.hdr.itemCount - base);
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for (uint k = 0u; k < lim; ++k)
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if (s_keep[k] != 0u) s_order[n++] = k;
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s_count = n;
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}
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barrier();
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if (valid) {
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for (uint j = 0u; j < s_count; ++j) {
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uint c = s_order[j];
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vec2 lo = s_rect[c].xy;
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vec2 hi = s_rect[c].xy + s_rect[c].zw;
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if (sp.x < lo.x || sp.y < lo.y) continue;
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if (sp.x >= hi.x || sp.y >= hi.y) continue;
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vec2 t = (sp - s_rect[c].xy) / s_rect[c].zw;
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vec2 uv = mix(s_uv[c].xy, s_uv[c].zw, t);
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float sdf = texture(
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sampler2D(uiTextures[nonuniformEXT(pc.fontTextureSlot)],
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uiSamplers[nonuniformEXT(pc.fontSamplerSlot)]),
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uv
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).r;
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// Distance in atlas-pixels (negative inside the glyph).
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float dAtlas = (ON_EDGE - sdf) * DIST_SCALE;
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// Atlas-px per screen-px along this glyph's transform — keeps AA crisp
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// at any rendering size. uvSpan * atlasSize / screenSpan.
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vec2 uvSpan = s_uv[c].zw - s_uv[c].xy;
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// FontAtlas::kAtlasSize = 1024.
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vec2 atlasPerScreen = (uvSpan * 1024.0) / s_rect[c].zw;
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float scalePx = max(atlasPerScreen.x, atlasPerScreen.y);
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// 1-screen-px AA band, expressed in atlas-pixel units of dAtlas.
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float band = max(scalePx, 0.0001);
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float a = clamp(0.5 - dAtlas / band, 0.0, 1.0);
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if (a <= 0.0) continue;
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vec4 col = s_color[c];
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vec4 src = vec4(col.rgb, col.a * a);
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dst = uiBlendOver(dst, src);
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}
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}
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barrier();
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}
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if (valid) imageStore(uiImages[pc.hdr.outImage], screenPx, dst);
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}
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