This is way too much for the poor memory bus. That is, each fragment will be written 10, 20 times, maybe more. I wonвЂ™t dig in the details, becauseвЂ¦ CaveatДoing so will work ( more on this in the next section ), but : You can sort whatever you want with qsort (in C) or std::sort (in C++). Sort transparent triangles, from the furthest to the closest.Draw the opaque part of the world so that the depth buffer already can reject hidden transparent triangles.The usual solution is to sort all transparent triangles. You never see lots of transparency in games, do you ? Usual solution It turns out that this is a very hard problem.

This phenomena also happens in our scene. You can see that order is important, the final colour gives an important clue to the eyes for proper depth perception. Here, I drew two squares with 50% alpha, one green and one red. The previous screenshot looks okay-ish, but thatвЂ™s just because weвЂ™re lucky. Make sure to turn backface culling off (glDisable(GL_CULL_FACE) ) because since we can look through the mesh, we could see that it has no вЂњbackвЂќ face. Here, we simply hardcode the alpha channel at 0.3, but you probably want to use a uniform, or read it from a RGBA texture ( TGA supports the alpha channel, and GLFW supports TGA ) Unintuitively, alpha = opaqueness, so alpha = 1 means fully opaque while alpha = 0 means fully transparent.

Z transparent popclip extensions