Re: GL_BLEND
Glynn Clements <[email protected]>
| Newsgroups | gmane.comp.lang.haskell.hopengl |
|---|---|
| Message-ID | <[email protected]> |
Sven Panne wrote:
> Glynn Clements wrote:
> > Does this rely upon the underlying OpenGL implementation/driver
> > supporting glBlendEquation() (i.e. OpenGL 1.3 or 1.2+GL_ARB_imaging)?
>
> Yes, blendEquation depends on the glBlendEquationEXT extension function.
> If the extension is not supported, an exception with the message
>
> unknown OpenGL call glBlendEquationEXT, check for GL_EXT_blend_minmax or GL_EXT_blend_subtract or OpenGL 1.4
>
> should be thrown, not a segfault. This is a bit mysterious...
That's a bug in the HOpenGL API.
Whilst glBlendEquation() requires GL_ARB_imaging or 1.3, glBlendFunc()
and gl{Enable,Disable}(GL_BLEND) are in OpenGL 1.0. If you want to
"merge" gl{Enable,Disable}(GL_BLEND), it should be merged with
glBlendFunc(), not glBlendEquation().
--
Glynn Clements <[email protected]>