Blending on PSX

[Micky]

I already have Halkun's PSX doc and did some Google search, but there are two bits still unclear:
- There is a special case for colour 0x0000. If it is marked as transparent, does it take part as "black" in the blend operation, or is it like an alpha-kill that doesn't write the pixel into the frame buffer at all?
- What are the rules for untextured polys? Do they just get blended as a whole if alpha blend is enabled?

[Gemini]

1) Pure black is always invisible, no matter the attributes of a primitive.
2) Simple polygons follow exactly the same rules as other draw primitives with tpage flags indicating transparency is enabled.

[Micky]

Thank you, that's a massive improvement. I wasn't totally sure about the 0x0000 thing, but it makes a significant difference.