docs: Phase 3 architecture — visuals, lighting, profiling pipeline

docs/visuals-architecture.md

@@ -0,0 +1,48 @@
+# Phase 3 — Visuals & Performance Architecture
+
+## Scope
+Art pass, baked lighting, performance profiling, LOD + occlusion culling for the competitive tactical shooter.
+
+## Dependency Chain (Kanban)
+
+```
+t_p3_artkit  (modular wall/floor kit + PBR materials 1K + art style guide)
+    └── t_p3_lighting  (LightmapGI baked lighting + reflection probes)
+           └── t_p3_profile  (perf budget + LOD + occlusion culling)
+```
+
+## Art Style
+
+- **Valorant-direction**, not AAA photorealistic
+- Clean silhouettes, team-colored zones (CT/blue, T/red-orange)
+- 1K PBR textures (base color, normal, roughness, metallic)
+- CC0-licensed or custom-created assets
+
+## Lighting Strategy
+
+- LightmapGI for all static geometry
+- Reflection probes at corridor junctions and open areas
+- No SDFGI or real-time GI
+- Lightmap texel density: 4-8 per unit walls/floors, 8-16 for focal surfaces
+
+## Performance Budget
+
+| Metric | Target |
+|--------|--------|
+| Frame time | 16ms (60fps) |
+| GPU budget | 8ms |
+| CPU budget | 6ms |
+| Draw calls | 1500-2000 per frame |
+| VRAM | 2GB texture pool |
+| LOD0 tris/wall | 500-2000 |
+
+## LOD Strategy
+
+- 3 LOD levels per modular asset
+- LOD1 at 15m (50% tris), LOD2 at 40m (25% tris), LOD3 at 80m
+- Occlusion culling via OccluderInstance3D auto-generation
+
+## Reference Hardware
+
+- GTX 1050 / RX 560 class GPU (or integrated graphics)
+- Godot Forward+ renderer