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ycp

By "triangles positioned on screen"/"primitive generation" does that mean every single vertex is connected to every other one (basically like a complete graph) or are just some of the vertices connected?

kayvonf

The are several modes of how to group vertices into triangles. The simplest is to say every group of three vertices in the input vertex stream defines a triangle. More complicated modes also exist, as the triangle strip, shown here. A full listing of OpenGL supported primitive modes is here.

dfarrow

In the past while dabbling in OpenGL, it was always strange to me why they decided to call "fragment shaders" what I thought of as "pixel shaders". Now it all makes sense. The fragment shaders that you write in GLSL determine the color of a pixel-like object, which is called a fragment. But, the actual color of the pixel on the screen is a combination of fragments. OpenGL blends those overlapping fragments differently depending on whether or not blending is enabled and what the blend function is set to.