I’m coulouring GL_QUADS in ortho view which works fine, however when I switch the view to perspective the GL_QUADS are no longered coloured properly. You can see though them and the colouring varies as I zoom in and out.
z-buffering not precise enough?
in the glFrustum or gluPerspective call, make the zFar/zNear ratio as small as possible by pushing zNear out and zFar in as close around your objects without clipping them.