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Blending in the fixed-function pipe

Started by Scoob Droolins Mar 17, 2005 at 3:53 PM 1 replies 750+ views

Original Post

Mar 17, 2005 at 3:53 PM

A typical older video card will show these caps: MaxTextureBlendStages = 8, MaxSimultaneousTextures = 2. So, can I do the following DX7 blend in one pass, which is (Tex1 + Tex2) * Diffuse: Stage0: ColorOp=SelectArg1, ColorArg1=Texture Stage1: ColorOp=Add, ColorArg1=Texture, ColorArg2=Current Stage2: ColorOp=Modulate, ColorArg1=Diffuse, ColorArg2=Current Using 3 stages, but only the first two contain bound textures. Just wondering if I'm interpreting the SDK docs correctly? Thanks for any info.

jollyjeffers

Mar 17, 2005 at 4:13 PM

Your best bet is to try it and see [smile]

But, and its been a while, if I remember correctly, then the MaxSimultaneousTextures field (being 2) means it'll only use the stage-0 and stage-1 fields of IDirect3DDevice9::SetTexture( ), which directly map to your texture stage states #0 and #1. Thus, no, you cant.

As I said, its been a while - so I could be wrong.
Jack

Muhammad Haggag

Mar 17, 2005 at 4:35 PM

I believe it could work - you only have 2 bound textures on 2 stages. Theoretically, you can use the remaining 6 stages for whatever you want. Practically, old cards have a fixed blending equation that they try to map your TSS to. Usually they can't - they only support using the 8 stages in very special cases.

EDIT: In short, try it and see [smile]

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