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In multi-texture (MT) mode the static PIXI.WebGLRenderer.textureArray cache records which texture is bound to each texture unit. Several code paths rebound units without updating it, and WebGLSpriteBatch.renderBatch bound the first texture of a batch on whichever unit was active, so sprites drew with the wrong texture. Only one texture per batch was uploaded in MT mode, so late-loaded or changed canvas textures rendered blank or stale.

Cache correctness

• Add PIXI.WebGLRenderer.invalidateTextureUnit(unit?).
• updateTexture / updateCompressedTexture now record the bound texture in the cache.
• renderBatch no longer binds the first texture on the active unit in MT mode (non-MT path unchanged).
• Invalidate the cache where other code rebinds units: initContext, PixiShader (initMultitexShader, initSampler2D, syncUniforms), Rope, Creature, WebGLFilterManager push/pop, FilterTexture._CreateFramebuffer.

Upload gap

• WebGLSpriteBatch.render, renderTilingSprite (new bindMultiTexture helper) and WebGLFastSpriteBatch.renderSprite/render now flush and updateTexture dirty base textures; sprites whose texture isn't loaded yet are skipped.

Filters

• pushFilter now unbinds unit 0 after creating/resizing the filter texture. Previously the old renderBatch bind hid a feedback loop (filter target left bound while rendered to), which Chrome reported as GL errors once the bind was removed.

Testing

• Test page with 24 prioritized textures (more than fit without unit conflicts), Rope, filtered sprite, tilesprite, sprite batch, late-loaded texture and changing Text, with temporary instrumentation (not committed) comparing the cache to actual GL bindings. Before: ~92k stale-unit hits in 2.5 s and mostly black sprites. After: 0 hits and everything renders. Non-MT mode renders correctly.
• eslint src and npm run build-test pass.

Known, not addressed here

• Context loss/restore via WEBGL_lose_context doesn't recover, before or after this change (shaders/buffers from the old context are reused; Cache.clearGLTextures doesn't mark textures dirty).
• In MT mode Rope doesn't set aTextureIndex for the strip shader, so it can sample the wrong unit.

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[Copilot]

🟡 Changes recommended

Texture-binding errors remain during TileSprite uploads, first-use shader initialization, and RenderTexture resizing.

3 open issues

• Flush before TileSprite tiling texture upload · New
• Invalidate texture cache when FilterTexture resizes · New
• Restore textures after first-time sprite shader initialization · New

_{Review effort: Balanced}

[Copilot]

Flushed the sprite batch before the eager TileSprite texture upload in 6cb50ea.

[Copilot]

Restored the cached texture bindings after first-use multi-texture shader initialization in 6cb50ea.

[Copilot]

🟡 Changes recommended

Removing the batch rebind leaves a RenderTexture feedback loop that can cause WebGL to reject draws using prioritized source textures.

3 open issues

• Unbind RenderTexture from sampler units before WebGL rendering · New
• Restore textures after first-time sprite shader initialization
• Flush before TileSprite tiling texture upload

1 resolved since last review

• Invalidate texture cache when FilterTexture resizes

_{Review effort: Balanced}

[Copilot]

🟡 Changes recommended

The shared texture cache can still cause incorrect sampling across renderers now that the draw-time binding is removed.

4 open issues

• Scope texture binding cache by WebGL context · New
• Unbind RenderTexture from sampler units before WebGL rendering
• Restore textures after first-time sprite shader initialization
• Flush before TileSprite tiling texture upload

_{Review effort: Balanced}