Depth-stencil texture get corrupt after reading

OpenGL OpenGL: Advanced Coding
1

I have this strange problem about reading from depth-stencil texture

I tried to add stencil test to my already working deferred rendering engine.
So I create FBO with the following pack depth-stencil attachment.



glGenTextures(1, &depthBufferTexID);
glBindTexture(GL_TEXTURE_2D, depthBufferTexID);

/*1*/glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH24_STENCIL8,  width, height, 0, GL_DEPTH_STENCIL,GL_UNSIGNED_INT_24_8, NULL);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_NEAREST);

/*2*/glFramebufferTexture2D(GL_FRAMEBUFFER,GL_DEPTH_STENCIL_ATTACHMENT, GL_TEXTURE_2D,depthBufferTexID, 0);

I attached depth-stencil as a texture instead of render buffer
so that I can directly read from depth texture in lighting pass(to reconstruct vertex position ,etc…)

Actually the only thing I change from my whole source code is the line mark with /1/ and /2/

But after reading from the depth-stencil texture(to reconstruct vertex position in lighting pass),the depth-stencil texture appear to be corrupt.

Any depth-testing enabled rendering perform after the depth-stencil texture reading appered to had some weird hole on them,it is very hard to describe (picture below).

//corrupt picture

If I comment out the texture reading pass(the deferred lighting pass on background geometry),the subsequence rendering pass appeared correct.

//correct behavior picture

I dont think there are anything in the rendering process that can cause this,If I remove the line /1/ and /2/ and go back to using depth only attachment every thing worked again.

Note that in the whole process I didn’t even doing any stencil-related operation once.

Has anyone ever encouter something like this ?

test on ATI HD4670 with 10.5 driver.

Thank in advance.

2

UPDATE

Just try with ATI catalyst 10.6 driver and it still the same , weird hole on any object render after depth-stencil texture reading.

My brother’s geforce 9800gt doesn’t has this problem , any object render after the problematic depth-stencil texture reading are correctly drawn.

Guess I could avoid this by making a copy of depth-buffer(using blitting) just for reading or use my own depth format , but I would like to know the cause of the problem since this is very weird.

3

UPDATE

I decided to continue, by writing linear z into seperate buffer (GL_R32F formats) and use that instead of the old depth-stencil texture and just attach depth-stencil as render buffer.

This way I can using stencil test/depth reading in FBO with out any error on ATI.

But I still want to know what cause the error after reading the depth-stencil texture on ATI too since using seperate float buffer to store z/depth is a little slower compare to depth-texture solution.

4

We can’t reproduce the problem right now.
Could you please narrow down the problem and paste the whole codes to us?
Do you use lighting in your application?

5

Thank for your reply,I will try to create a test application.

It might take a long time too since I already modified that part of application to use the linearZ method and also had a deadline for my main job.

I think this one may be (again) my stupid mistake and yes I use shader for lighting (both deferred and forward part/no mixing of fixed-function code).

Thank :slight_smile:

somboon