View Full Version : EXT_shader_framebuffer_fetch - On desktop?

Ed Daenar
08-24-2014, 07:34 AM

Going through some documents I came across this extension for GLES. In a nutshell:

This extension provides a mechanism whereby a fragment shader may read existing framebuffer data as input.

Now, I've searched for something similar on desktop GL and there's nothing I could find even in the latest 4.5 specs. I'm wondering if there's anything stopping Khronos from adding this extension (or something similar) to desktop GL.

I realize the same (and much more) can be achieved with render targets so it is somewhat redundant, but often times one finds the need to simply use blending operations and this seems like the perfect way to detach blending from the application logic, which might be a desirable choice for some designs.

08-24-2014, 08:03 AM
Strongly vote for that. I also don't understand why the fixed-functionality blending is not deprecated yet.

08-24-2014, 10:00 AM
Read: "Why no fully programmable blend? (http://fgiesen.wordpress.com/2011/07/12/a-trip-through-the-graphics-pipeline-2011-part-9/)"

The closest option on desktop GPUs is NV_texture_barrier (http://www.opengl.org/registry/specs/NV/texture_barrier.txt) (recently promoted (http://www.opengl.org/registry/specs/ARB/texture_barrier.txt).)

Ed Daenar
08-28-2014, 06:11 PM
Thank you, this extension does provide pretty much the same functionality and it's recent promotion makes it even more interesting.