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Pellebert

2D MMX Alpha Blending

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I''ve read the document about Alpha Blending with MMX and tried the example. But i have a little problem. My grafic card uses the 5-5-5 type of 16-bit color mode, and the mmx-effect looks very wierd on my computer. Is there anyone who knows how to fix to code so it also works in 555 mode??? You can find the article here: http://www.gamedev.net/reference/programming/graphics/article817.asp

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Ahh, the code is for a 565 mode. What you need to do is replace any 0x3f masks with 0x1f (3f hex is 111111 binary, you want 5 bits not six) then change any bit shifts of 11 to 10, red is one bit more to the right in 555 mode.

hope this helps, if you post your code then I could show you exactly whats wrong with it.

happy coding

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did you download the sourcecode? it claims to run on 555 systems as well, although the author says he hasn''t tested it.
it would be very interesting if it does, as i am using the same alpha blitter and don''t have a testplatform with RGB555

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If I remember it correct it should work if you change his masks, one (or a few?) of them was incorrect in the 555 version.



"I think, therefore I am...I think"

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