View Full Version : Creating a depth texture to use in GLSL

03-25-2010, 03:33 PM
I'm trying to figure out how to create a depth texture that I can use from frame to frame in C++ / GLSL.

Lets say on frame number one I set gl_FragDepth of a few random pixels to 0.5. Before rendering frame 2, I'd like to apply the depth state to a texture. This way, in frame 2, I can determine which texels are at 0.5 so I can further manipulate them.

I can't seem to find any clear tutorials/reference/instructions on how to do this.

Alfonse Reinheart
03-25-2010, 03:46 PM
Assuming input from your previous thread is valid, you aren't really using the depth value for actual depth comparison. So it doesn't need to be a depth texture at all; it can just be a floating-point texture that you write a value to.

In either case however, what you're looking for is direct rendering to a texture. To do that, you need to use Framebuffer Objects (http://www.opengl.org/wiki/Framebuffer_Object).

03-25-2010, 03:59 PM
Thank you! Exactly what I'm looking for.

And you're right... I really just need numbers to compare. Depth seemed like the natural thing to use.