Deferred Shading, MRT and Depth Test

OpenGL OpenGL: Basic Coding
1

Hello,

I’m currently implementing a deferred shader with multiple render targets for albedo, normal and position. The depth test fails as soon as I set the “alpha” value for the normal or position texture to zero. How can I tell OpenGL to use only the albedo texture for its depth tests? Or am I thinking in the wrong direction?

Depth Test is enabled during geometry render (glEnable(GL_DEPTH_TEST)) and disabled when I call the deferred shading.

My Setup for the depth looks like this:
glGenRenderbuffers(1, &ids[depthbuffer]);
glBindRenderbuffer(GL_RENDERBUFFER, ids[depthbuffer]);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, dim[0], dim[1]);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
GL_RENDERBUFFER, ids[depthbuffer]);

and my fragment shader to fill the MRT:
lo_fragcolor1 = texture(u_texture, gs_texcoord);
lo_fragcolor2 = vec4(normalize(gs_normal) * 0.5 + 0.5, 0);
lo_fragcolor3 = vec4(gs_position, 0);

Any ideas?
Saski

2

What makes you think that the depth test is failing?

3

Hi,
Because objects appear to be partial tranaparent as if the alpha channels of the MRTs are being mixed somehow. Maybe I’m confusing this with a depth test fail.

Saski

4

problem solved! explicitly calling glDisable(GL_ALPHA_TEST) before rendering the geometry to MRTs did the job :slight_smile:

Saski