mesa: pin mesa-wink 60202246 (wink head); GL 4.1's texture limits by default

third_party/mesa moves from 5f5572e6 to 60202246, the wink branch's head
(gl/perf rebased onto upstream wink 0dd84167). Its webgpu.cpp needs
emdawnwebgpu v20250822 (WGPUTextureFormat_R16Unorm, std::span), which
the wink branch pins and patches itself: web/build-mesa-wasm.sh now gets
it from the checkout's wink/build.sh (--until=emdawn) when the checkout
has wink/lib/emdawn.sh, and keeps fetch-emdawnwebgpu.sh otherwise (as it
already does for Tint). The page build's JS is byte-identical to GL's
mods/gpu build of the same commit.

gpu-device.js asks for GL 4.1's texture limits (16384 texels a side,
2048 array layers; clamped to the adapter's) unless the page says
otherwise: `?gllimits=0` is WebGPU's defaults (GL 4.0), 43 adds GL 4.3's
compute limits (GL 4.6, which drew Muck's 3D scene black: per run only).
At 4.0 Unity drops Muck's grass geometry shader and the grass is dots;
with this Mesa at 4.2 it draws blades (mpg3).

Checks on edger:
- Replays, GL's mods/gpu against this build (upin), 300 frames with
  readback: Noita 92f095c5 for both, HK 9eece5c5 for both; 0 rejects
  and 0 validation errors each.
- GL's 4-slot bind-group repro (mods/tinyu, the rebased tree with a
  4-slot cache), full Noita trace with --query stream=1: 2,777 frames,
  0 validation errors (5f5572e6 had 2,668 from frame 1343).
- browser-gui --gl --arch x86 and --arch x64 with this build and the new
  default: 12 ok and 0 failures each (234 and 213 frames).
- HK in the page (hp14, full fjit + the unit, this Mesa, no ?gllimits):
  the menu at 41.8 presents/s (hp13 on 5f5572e6: 39.6-39.9); first frame
  110 s with a CPU profile of 80 s running (hp13: 87 s without one).
- Muck (mpg5, fjit + unit) died with SIGILL at ~30 s, before any GL:
  the function JIT, not Mesa (being run down separately); the grass
  check with the default is still to come.

docs/gl-path.md: open items 2 (grass) and 5 (the repro) closed.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_1896c5b302a54696aaa92c5f4047f20b

docs/gl-path.md

@@ -51,21 +51,21 @@ push** (rebased onto upstream wink 0dd84167; nothing pushed):
    - replay it with `replay-run.mjs gpu TRACE --query readback=1`;
    - bisect the shader variants with `shaders.mjs`;
    - then re-apply e204fa1b's two web files.
-2. *Grass is still dots* at GL 4.0 after the -0.0 fix (U mp27; the sea is
-   back). Next: the geometry-shader emulation's output for the grass program
-   (its source is in the Muck trace; `shaders.mjs`). It may resolve with
-   item 1 at GL 4.1+, where Unity's 410 source compiles natively.
+2. *Grass:* fixed at GL 4.2 by GL 4.1's texture limits with mesa-wink
+   60202246 (U mpg3: blades, 36.6-38.1 presents/s). gex's pin is 60202246
+   and `?gllimits=41` is the default since U's pin commit on merge/unity
+   (`?gllimits=0` turns it off; 43 stays per run, item 1).
 3. *Noita's world fps* is bound by its job hand-off, not by GL: the main
    thread is parked about 37% waiting on job threads, and KLock is 0.14%
    (stream F's area). The page's GL submit is no longer the limit
    (CLIENT_ARRAY: 55.5 vs 51.1 world fps on the old path, pewasm 47.2).
 4. Remaining E1: GL draw/pointer calls are on the fast path, but the page
    gain is below noise.
-5. *The 4-slot bind-group repro on the rebased tree* (`$G/urep5.sh`, mods
-   tinyu) timed out at 1200 s with no output. Rerun it the way trep2.sh ran
-   the earlier ones (full trace, `--query stream=1`, timeout 1500, no
-   maxframes) before moving gex's pin; expect 0 validation errors from
-   frame 1343 on.
+5. *The 4-slot bind-group repro on the rebased tree:* done (U,
+   2026-10-09, `scratch/unity/urep-pin.sh` on edger, run like trep2.sh:
+   full trace, `--query stream=1`, timeout 1500): mods/tinyu replays all
+   2,777 frames (3,403 batches) of Noita's trace with 0 validation errors
+   (5f5572e6 and +6d3a4cfd had 2,668 and 2,720 from frame 1343).
 
 Tooling (unchanged):
 

web/build-mesa-wasm.sh

@@ -20,7 +20,26 @@ else
 fi
 OUT=${1:-$DEFAULT_OUT}
 BUILD=$OUT/build
-EMDAWN=${GEX_EMDAWN_DIR:-$($ROOT/web/fetch-emdawnwebgpu.sh)}
+# emdawnwebgpu: a Mesa checkout that pins its own (the wink branch:
+# wink/lib/emdawn.sh, a release matched to its Tint and patched by
+# wink/tools/patch-emdawnwebgpu.py) supplies it; else gex's own fetch.
+if [ -z "${GEX_EMDAWN_DIR:-}" ] && [ -f "$MESA/wink/lib/emdawn.sh" ]; then
+    WINK_CACHE=${GEX_MESA_WINK_CACHE:-${TMPDIR:-/tmp}/gex-mesa-wink-cache}
+    EMSDK_ROOT=$(CDPATH='' cd -- "$(dirname "$(command -v emcc)")/../.." && pwd)
+    emdawn_log=$(WINK_ALLOW_ANY_EMSDK=1 bash "$MESA/wink/build.sh" --variant=mt --until=emdawn \
+        --cache="$WINK_CACHE" --build-dir="$WINK_CACHE/build" --emsdk="$EMSDK_ROOT" 2>&1) || {
+        echo "$emdawn_log" | tail -20 >&2
+        exit 1
+    }
+    EMDAWN=$(echo "$emdawn_log" | sed -n 's/^\[emdawn\] \(ready\|cached\) at //p' | tail -1)
+    [ -f "$EMDAWN/webgpu/include/webgpu/webgpu.h" ] || {
+        echo "$emdawn_log" | tail -20 >&2
+        echo "no emdawnwebgpu from wink/build.sh" >&2
+        exit 1
+    }
+else
+    EMDAWN=${GEX_EMDAWN_DIR:-$($ROOT/web/fetch-emdawnwebgpu.sh)}
+fi
 TINT_OUT=${GEX_MESA_TINT:-${TMPDIR:-/tmp}/gex-mesa-wasm/mesa-tint-pthread}
 TINT_TMP=${GEX_MESA_TINT_TMP:-${TMPDIR:-/tmp}/gex-mesa-tint-build}
 

web/src/compositor-worker.js

@@ -1440,7 +1440,7 @@ self.onmessage = ({ data: m }) => {
       canvas = m.canvas;
       presentOverride = m.present ?? null;
       // The compositor draws with WebGPU on the device Mesa will use.
-      if (m.glLimits) globalThis.GEX_GL_LIMITS = m.glLimits;
+      if (m.glLimits != null) globalThis.GEX_GL_LIMITS = m.glLimits;
       requestGexDevice().then((gpu) => {
         comp = new Compositor(m.canvas, m.channel, m.stats ? new Int32Array(m.stats) : null, gpu);
         comp.setDirect(m.direct);

web/src/compositor.js

@@ -137,10 +137,11 @@ export class Compositor {
     // is the canvas, fitted to the viewport; compositing only when needed.
     const direct = pq?.get('direct') === '1';
     this.#pointerLock = pq?.get('pointerlock') === '1';
-    // `?gllimits=41|43`: the device asks for GL 4.1's texture limits (and
-    // 4.3's compute ones), raising the GL version Mesa's context earns
-    // (gpu-device.js). Off by default: at 4.6 Muck's 3D scene drew black.
-    const glLimits = Number(pq?.get('gllimits')) || 0;
+    // `?gllimits=40|41|43`: the device asks for WebGPU's default limits,
+    // GL 4.1's texture limits (the default), or 4.3's compute ones too,
+    // which decide the GL version Mesa's context earns (gpu-device.js). At
+    // 4.6 Muck's 3D scene drew black, so 43 is only per run.
+    const glLimits = pq?.has('gllimits') ? Number(pq.get('gllimits')) || 0 : null;
     worker.postMessage(
       { kind: 'init', canvas: offscreen, channel, stats: this.#stats, present, direct, glLimits },
       [offscreen],

web/src/gpu-device.js

@@ -44,17 +44,20 @@ export function requestGexDevice() {
       maxStorageBuffersInVertexStage: 16,
       maxStorageBuffersInFragmentStage: 16,
       maxColorAttachmentBytesPerSample: 64,
-      // Not by default yet: GL 4.1's texture limits and GL 4.3's compute
-      // ones (all of them make the context GL 4.6) drew Muck's 3D scene
-      // black (U, mp26); `?gllimits=` below asks for them per run.
+      // GL 4.3's compute limits (with them the context is GL 4.6) drew
+      // Muck's 3D scene black (U, mp26), so they are only per run; GL 4.1's
+      // texture limits are the default, below.
     };
-    // `?gllimits=41|43` (GEX_GL_LIMITS, set by the compositor worker): GL 4.1
-    // wants 16384 texels a side and 2048 array layers, GL 4.3's compute
-    // shaders 1024 invocations a workgroup and 32 KiB of shared memory;
-    // WebGPU's defaults (8192, 256; 256, 16 KiB) keep the context at GL 4.0.
-    // Unity drops shaders whose target the context is below (Muck's grass
-    // geometry shader: "Shader Unsupported ... All passes removed").
-    const glLimits = Number(globalThis.GEX_GL_LIMITS) || 0;
+    // `?gllimits=40|41|43` (GEX_GL_LIMITS, set by the compositor worker;
+    // 41 when unset): GL 4.1 wants 16384 texels a side and 2048 array
+    // layers, GL 4.3's compute shaders 1024 invocations a workgroup and
+    // 32 KiB of shared memory; WebGPU's defaults (8192, 256; 256, 16 KiB)
+    // keep the context at GL 4.0. Unity drops shaders whose target the
+    // context is below: at 4.0 Muck's grass geometry shader ("Shader
+    // Unsupported ... All passes removed") left the grass as dots; at 4.2
+    // with mesa-wink 60202246 it draws blades (U, mpg3).
+    const glLimitsSet = globalThis.GEX_GL_LIMITS;
+    const glLimits = glLimitsSet === undefined ? 41 : Number(glLimitsSet) || 0;
     if (glLimits >= 41) {
       Object.assign(want, { maxTextureDimension1D: 16384, maxTextureDimension2D: 16384,
         maxTextureDimension3D: 2048, maxTextureArrayLayers: 2048 });