GXSetTevAlphaOp

• Category: Texture Environment
• Matrix Status: Implemented
• Matrix Notes: Implemented alpha combiner op/bias/scale/clamp-enable/output configuration.
• Matrix Link: Gfx-GX-API-Matrix

Official SDK (Reference)

• Manual page: reference/man/gfx/gx/Tev/GXSetTevAlphaOp.html
• SDK source: reference/ACGC-PC-Port/src/static/dolphin/gx/GXTev.c (GXSetTevAlphaOp)
• SDK behavior:
  • Programs TEV alpha op, bias, scale, clamp flag, and destination register for one stage.
  • Supports add/sub ops and HW2 compare ops (GX_TEV_COMP_*).
  • For compare ops, HW register encoding forces compare-mode path (bias field encoded as compare selector).
  • SDK debug path asserts on invalid stage.

libPorpoise Implementation

• Public API declaration: include/dolphin/gx/GXTev.h
• Runtime implementation: src/gx/pc_gx.c (GXSetTevAlphaOp)
• Behavior:
  • Stores op/bias/scale/clamp/out_reg per TEV stage and marks TEV state dirty.
  • BP display-list decode path maps compare-encoded BP state into GX_TEV_COMP_* op values before calling setter.

SDK vs Porpoise Diff

• Signature parity:
  • Signatures match.
• Behavioral parity:
  • Add/sub op state wiring matches.
• Known divergence:
  • SDK compare-op behavior is explicitly encoded in TEV pipeline semantics; current PC shader tevStage path handles add/sub but does not fully implement GX_TEV_COMP_* alpha compare semantics yet.
  • SDK debug asserts invalid stage; Porpoise fail-soft ignores out-of-range stage.

Validation Checklist

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

Working Notes

• No runtime code change required in this pass; compare-op divergence is documented for follow-up.