scaling alpha, color array, fixed function...

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0 comments, last by Brother Bob 19 years, 4 months ago
Is there a way to scale the alpha component of a color array when rendering, only using the fixed function pipeline. I know you can scale the RGB component up by 2 or 4 times but i dont think this affects the alpha. This would be easily done with vertex programs / glsl etc but i need to create a fallback for cards that dont support it. What i'm looking for is blending in a detail layer to a surface as the viewer gets closer to it, the detail and base layer uses the same geometry data (vertex, color, texture arrays). This is why i want to modify the alpha component of the color stream (scale it), doing this on the cpu per frame(s) will be too slow. So is there anyway i can do this, different method then what i'm planning to use, or should i just thrash the low end and use vp/fp/glsl programs to do it. btw I dont have register combiner support either :( Thanks in advance
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GL_ALPHA_SCALE is exactly the same as GL_RGB_SCALE, but for the alpha channel.

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