API Per Pixel Alpha-Blending

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3 comments, last by TroneX 21 years ago
I want to create a splash screen which basically presents itself as a non-rectangular image which has "fuzzy" edges that blend out. For this I already have the image which an alpha mask containing the alpha values for each pixel. To get this working with windows 9x as well, I first make a screenshot of the part of the screen, I want to blend over the splash screen. Having this, I now want to alpha blend my splash screen over the screenshot (on a per-pixel basis) and write the result back to the screen. How do I do this? There are several API functions from MS which seem to be able to do this, but I cannot figure out, how they work. Next problem is, that I need a fileformat which can be read without problems (preferebly BMP) and which also contains the alpha values in a way that the API functions understands them .. Does anyone have an example for this? Buy BomberFUN online now for only EUR/USD 19,95 at http://www.bomberfun.com
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Allright ... in case you already thought of a solution, thanks a lot. But Actually, I finally managed to solve that problem on my own ;-)

Regards,
TroneX

Buy BomberFUN online now for only EUR/USD 19,95 at http://www.bomberfun.com
are there 32 bit bitmaps? what did you do?
Programmers of the world, UNTIE!
I actually use the targa file format now (.tga) which is perfectly suitable for my needs, since it does not only support any bitrate but is even capable of including alpha masks ;-)

For this I found some sample code on the net which let''s me load a tga file into the memory and also pre multiplies the pixels with the alpha values.

Greetz,
Tronex

Buy BomberFUN online now for only EUR/USD 19,95 at http://www.bomberfun.com
cool. Thanks!
Programmers of the world, UNTIE!

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