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MatrixCubed

OpenGL Blending texture edges

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MatrixCubed    199
Hello all, A situation has arisen where I wish to add an effect to my game engine. It's a 2D sprite engine which uses OpenGL as the workhorse. Currently what I'm doing at texture-loading time is: - load PNGs using SDL_Image (IMG_Load) into an SDL_Surface - iterate pixel by pixel through the SDL surface to add alpha=0 to color-keyed pixels, or alpha=255 for opaque pixels - load this into an OpenGL texture as a 32 bit RGBA texture What I want to try doing is giving 50% alpha to pixels which border both opaque and transparent pixels. I figure this will give a smooth look to the game engine, but who knows, it might totally suck, I just want to see what the end result will look like. :) Immediately I thought of performing a 2nd pass in the loading code, check surrounding pixels, and setting alpha that way. But to render textured polys with the desired effect, what renderstates do I need to set? Right now I use these to discard colorkeyed pixels: glEnable(GL_ALPHA_TEST); glAlphaFunc(GL_NOTEQUAL, 0.0f); Do I additionally need to add this to render pixels based on values contained in the alpha channel? glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE); Thanks in advance, - m³

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mc30900    100
umm i'm not sure i have understanded what you want to do but...
Tga and PNG format got an option to add a channel
and so they wont show anything in that channel
take a look at nehe lesson 32

hope i helped

mc

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