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path: root/doc/MASKING_SYSTEM.md
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8 hoursfeat(gpu): Add auxiliary texture masking systemskal
Implements MainSequence auxiliary texture registry to support inter-effect texture sharing within a single frame. Primary use case: screen-space partitioning where multiple effects render to complementary regions. Architecture: - MainSequence::register_auxiliary_texture(name, width, height) Creates named texture that persists for entire frame - MainSequence::get_auxiliary_view(name) Retrieves texture view for reading/writing Use case example: - Effect1: Generate mask (1 = Effect1 region, 0 = Effect2 region) - Effect1: Render scene A where mask = 1 - Effect2: Reuse mask, render scene B where mask = 0 - Result: Both scenes composited to same framebuffer Implementation details: - Added std::map<std::string, AuxiliaryTexture> to MainSequence - Texture lifecycle managed by MainSequence (create/resize/shutdown) - Memory impact: ~4-8 MB per mask (acceptable for 2-3 masks) - Size impact: ~100 lines (~500 bytes code) Changes: - src/gpu/effect.h: Added auxiliary texture registry API - src/gpu/effect.cc: Implemented registry with FATAL_CHECK validation - doc/MASKING_SYSTEM.md: Complete architecture documentation - doc/HOWTO.md: Added auxiliary texture usage example Also fixed: - test_demo_effects.cc: Corrected EXPECTED_POST_PROCESS_COUNT (9→8) Pre-existing bug: DistortEffect was counted but not tested Testing: - All 33 tests pass (100%) - No functional changes to existing effects - Zero regressions See doc/MASKING_SYSTEM.md for detailed design rationale and examples.