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PeterV

Writing alpha values to backbuffer

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Hi, I´ve rendered a few objects to the screen that had each their own alpha value output in the pixel shader. When I lock the back buffer and read the pixels I want to be able to identify the objects by reading the alpha value. (This in done in the tools, not in the game, slow speed is not an issue) What I don´t understand is that all alpha values in the back buffer are 0. I can read the all colors, those are exactly what I put out in the pixel shader, but the alpha values are not affected. Is that normal behavior? How do I make the alpha channel behave the same as the three color channels? Peter

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What is the pixel format of your backbuffer? Are you using something that contains an alpha channel (such as D3DFMT_A8R8G8B8)?

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