- V4 store (vmovups) writes xyz+color as one 16-byte op instead of 4
scalar stores. Unaligned but still 1 μop on modern CPUs.
- inline for unrolls 4-vertex loops, letting LLVM schedule stores
across vertices and fill pipeline bubbles.
- Hoisted world_pos to locals to prevent array re-reads.
- A/B: BASELINE ~433ms → CUSTOM ~299ms (~31% per-period reduction).
Total from original: 520ms → 299ms = 42% reduction.
- Detected interleaved 24-byte vertex layout: xyz(12)+color(4)+uv(8).
Fast path writes 6 sequential u32s instead of scattered stores.
- Normal stride=0 (shared global) — write once in writeback, not 4x.
- Added stride_info export + logging for vertex layout analysis.
- A/B: ~30% peak reduction, baseline also improved due to less overhead.
- VBState caching on all 5 vertex paths (was only 2D and sin/cos).
Eliminates pointer re-reads: load once, emit 4 vertices, writeback.
- Cache setupRender() result per-frame via static + resetParticleCache()
called from worldUpdateDetour. Saves ~7K function calls/frame.
- @mulAdd throughout for FMA codegen on vertex position and texcoord.
- A/B verified: BASELINE ~521ms → CUSTOM ~387ms (~25% reduction).
- Inline calcColor: eliminates function call, allows OoO overlap of
cache misses on colorCtx with vertex math. Pow path falls back to
game function.
- Inline mat*vec3 transform: V4 FMA chain replaces call to 0x7BCA80.
- VBState: cache VB pointers/strides in locals, write back once after
4 vertices. Eliminates ~80 pointer re-reads per particle.
- @mulAdd throughout vertex loops for FMA codegen.
- A/B verified: BASELINE ~470ms → CUSTOM ~382ms (~20% reduction).
Full recreation of RenderParticleSprites (0x7B2A50, 2688 bytes) in
particle_sse.zig. All 5 code paths: 2D billboard, 3D billboard,
2D+rotation (sin/cos), 3D+rotation (axis-angle matrix), tail particles.
Key fixes during verification:
- colorCtx address: removed Ghidra's spurious -0x12 offset
- calcColor arg2: pass raw u32 from emitter+0x1A8, not truncated
- Texture coord lookups: +8 offset to match assembly's eax increment
between position and texcoord reads in the vertex loop
Verified in-game: particles render identically in CUSTOM vs BASELINE.
Next: optimize with SSE (inline calcColor, V4 vertex math).
- Ghidra C decompilation of RenderParticleSprites (422 lines) and 5
helper functions (calculateColorValues, matVec3Transform, etc.)
- particle_sse.zig with calcColorValues_SSE (10.7x bench but cache-miss
bound in-game — needs inlining into full function replacement)
- Bench harness for calcColorValues with correctness check
- build.zig: particle_sse as separate ReleaseFast compilation unit
- colorDetour reverted to pass-through (SSE has no in-game effect due
to L1 cache misses on scattered ColorCtx structs)
MarcelineVQ