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>
103 lines
3.8 KiB
GLSL
103 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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// QuadItem 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 runs the per-pixel accumulate over only those
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// survivors. Item order in the buffer == draw order on screen.
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layout(push_constant) uniform PC {
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UIDispatchHeader hdr;
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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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// Per-chunk cooperative-cull scratch (one slot per workgroup thread).
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shared vec4 s_rect[UI_CHUNK];
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shared vec4 s_color[UI_CHUNK];
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shared vec4 s_corners[UI_CHUNK];
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shared vec4 s_outline[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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// NOTE: do not early-return — every thread must reach the barriers below.
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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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// Cooperative load: each thread reads one item member-by-member
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// (the NVIDIA descriptor-heap workaround) into shared and culls it.
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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] = uiQuadHeap[pc.hdr.itemBuffer].items[idx].rect;
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s_color[lid] = uiQuadHeap[pc.hdr.itemBuffer].items[idx].color;
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s_corners[lid] = uiQuadHeap[pc.hdr.itemBuffer].items[idx].corners;
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s_outline[lid] = uiQuadHeap[pc.hdr.itemBuffer].items[idx].outline;
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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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// Stable in-order compaction of this chunk's survivors.
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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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// Cheap pre-test against the item's axis-aligned rect.
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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 halfSize = s_rect[c].zw * 0.5;
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vec2 p = sp - (s_rect[c].xy + halfSize);
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float d = uiSdRoundRect(p, halfSize, s_corners[c]);
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vec4 outline = s_outline[c];
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float bodyA = clamp(0.5 - d, 0.0, 1.0);
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if (bodyA <= 0.0 && outline.x <= 0.0) continue;
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vec4 col = s_color[c];
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vec4 src = vec4(col.rgb, col.a * bodyA);
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if (outline.x > 0.0) {
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float t = abs(d + outline.x * 0.5) - outline.x * 0.5;
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float outlineA = clamp(0.5 - t, 0.0, 1.0);
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src.rgb = mix(src.rgb, outline.yzw, outlineA);
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src.a = max(src.a, outlineA);
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}
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if (src.a <= 0.0) continue;
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dst = uiBlendOver(dst, src);
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}
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}
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barrier(); // done reading shared for this chunk before it's overwritten
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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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