Original Post
I'm programming a beakout clone these days and i have some porblems. I'm making full use of drawing images with transpaerncy, more specific images that have an alpha value of 0.0f or 1.0f. The thing is i get some artefacts near the contour of the image and don't really understand why. When i'm rendering textured polygons and turn alhpa blending on like this glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); i think the artefacts occur because of the filtering of the texture. But the thing i don't understand is why do i get artefacts near the contour of the image when i'm sending pixels with glDrawPixels to the pipeline. Here is a screenshot from the game: http://img233.imageshack.us/img233/9919/imaginezj1.png Notice that the little "spikes" from the bottom are surrounded by black pixels. Those spikes are rendered with glDrawPixels. Why are there black pixels on the contour?