sig
type attrib_bit =
GL_ACCUM_BUFFER_BIT
| GL_COLOR_BUFFER_BIT
| GL_CURRENT_BIT
| GL_DEPTH_BUFFER_BIT
| GL_ENABLE_BIT
| GL_EVAL_BIT
| GL_FOG_BIT
| GL_HINT_BIT
| GL_LIGHTING_BIT
| GL_LINE_BIT
| GL_LIST_BIT
| GL_MULTISAMPLE_BIT
| GL_PIXEL_MODE_BIT
| GL_POINT_BIT
| GL_POLYGON_BIT
| GL_POLYGON_STIPPLE_BIT
| GL_SCISSOR_BIT
| GL_STENCIL_BUFFER_BIT
| GL_TEXTURE_BIT
| GL_TRANSFORM_BIT
| GL_VIEWPORT_BIT
end