Help With Depth Testing

Good Afternoon,

I am trying to write a shader using the refract pass that compares the depth at a given screen position with the depth at the same screen position from the previous passes. The goal being that I find the difference in depth between the object I am rendering and all others in the scene. Currently, this is what I am trying to do.

//this retrieves the previous depth at location
texture2D(sDepthBuffer, vScreenPos.xy).r;
//this retrieves the depth at the current fragment (this is done in the vertex and interpolated to the fragment)
GetDepth(gl_Position);

Perhaps this is not the correct way to achieve this. Could someone point me in the right direction? Thanks!

Just bumping this thread.

The goal being that I find the difference in depth between the object I am rendering and all others in the scene.

You need to have two depth textures. One is input as texture, the second is destination buffer for rendering,

That would make sense, given that OpenGL does not allow buffers to written to and read in the same pass. Could you show me how I would structure a render path or technique to accomplish this? I still don’t quite understand how shaders/materials/render paths/techniques work together.

Hello,

cadaver explained depth rendering in more detail: How xml rendering framework works to get depth?

Until more specific info comes to the thread, there are a number of depth texture threads that may be informative.

(other than, of course, the docs on Rendering that links to the subjects you mention)

HTH