GXSetTevSwapMode (HW2)

• Category: Texture Environment
• Matrix Status: Implemented
• Matrix Notes: Implemented per-stage raster/texture swap selectors with BP-field-width masking (2-bit each).
• Matrix Link: Gfx-GX-API-Matrix

Official SDK (Reference)

• Manual page: reference/man/gfx/gx/Tev/GXSetTevSwapMode.html
• SDK source: reference/ACGC-PC-Port/src/static/dolphin/gx/GXTev.c (GXSetTevSwapMode)
• SDK behavior:
  • HW2-only API selecting swap-table entries for raster and texture inputs on one TEV stage.
  • Writes ras_sel and tex_sel as 2-bit fields in TEV stage register.
  • SDK debug path checks GX-begin and asserts stage < 16.

libPorpoise Implementation

• Public API declaration: include/dolphin/gx/GXTev.h
• Runtime implementation: src/gx/pc_gx.c (GXSetTevSwapMode)
• Shader consumption:
  • Per-stage selectors uploaded via u_tev_swap[].
  • Applied with u_swap_table[] in src/gx/shaders/default.frag (applySwap path for stage tex/ras colors).
• Behavior:
  • Stores per-stage raster/texture swap selectors and marks TEV-stage state dirty.
  • Applies 2-bit masking (& 0x3) for each selector to mirror BP field semantics.
  • Guards writes with stage < 16.

SDK vs Porpoise Diff

• Signature parity:
  • Signatures match (GXTevStageID, GXTevSwapSel, GXTevSwapSel).
• Behavioral parity:
  • Per-stage raster/texture swap selector behavior is implemented and drives shader swap routing.
  • Selector bit-width semantics now match hardware fields.
• Known divergence:
  • SDK writes packed BP register state directly; Porpoise stores decoded state and evaluates in shader.

Validation Checklist

• GX demo coverage checked
• Pikmin usage path checked
• Matrix status updated if needed
• Notes updated with concrete file/function references

Working Notes

• Runtime parity tweak in this pass: 2-bit selector masking added.