How to mark certain pixels as Alpha (Erase Pixels) |
Parikshit Singh
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I want to erase pixels , mark them as alpha. I have tried the following
code. Uint32 *pixels = (Uint32 *)surface->pixels; pixels[20 * surface->w + 20] = SDL_MapRGBA(surface->format,255,255,255,0); surface->pixels = pixels; Though , 20x20 is still not alpha , I have tried it with SDL_MapRGBA(surface->format,0,0,0,255) and it paints the pixels as black. _______________________________________________ SDL mailing list http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org |
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How to mark certain pixels as Alpha (Erase Pixels) |
David Olofson
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Is this SDL 1.2 or SDL2? (Since you're using surfaces... If you're on
SDL2, I suspect you'd be better off using textures - but that depends on what you're doing.) Either way, you need to actually enable alpha blending to make use of the alpha channel. In SDL2, that's done with SDL_SetSurfaceBlendMode(). On Sat, Feb 6, 2016 at 2:28 PM, Parikshit Singh wrote:
-- //David Olofson - Consultant, Developer, Artist, Open Source Advocate .--- Games, examples, libraries, scripting, sound, music, graphics ---. | http://consulting.olofson.net http://olofsonarcade.com | '---------------------------------------------------------------------' _______________________________________________ SDL mailing list http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org |
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