PRB: Antialiased Polygons Not Drawn in OpenGL Antipoly Sample

CAUSE

The technique used in this sample uses alpha values rather than depth values to determine what to write to the color buffer. You need to first turn off the depth buffer, choose the (GL_SRC_ALPHA_SATURATE, GL_ONE) blend function, and then draw polygons from front to back. But the generic Windows NT and Windows 95 OpenGL implementation does not provide alpha buffer. The cAlphaBits field of the pixel format descriptor for all generic pixel formats is 0.