Graphics.Rendering.OpenGL.Raw.NV.OcclusionQuery
glGenOcclusionQueries
glDeleteOcclusionQueries
glIsOcclusionQuery
glBeginOcclusionQuery
glEndOcclusionQuery
glGetOcclusionQueryiv
glGetOcclusionQueryuiv
gl_OCCLUSION_TEST
gl_OCCLUSION_TEST_RESULT
gl_PIXEL_COUNTER_BITS
gl_CURRENT_OCCLUSION_QUERY_ID
gl_PIXEL_COUNT
gl_PIXEL_COUNT_AVAILABLE