glBindTexture(GL_TEXTURE_2D, textures[depth]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH24_STENCIL8_EXT, wWidth, wHeight, 0, GL_DEPTH_STENCIL_EXT, GL_UNSIGNED_INT_24_8_EXT, 0);
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
then..
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_TEXTURE_2D, textures[depth], 0);
GLSL access depth buffer from shader
Author
Hey guys, I want to read the depth buffer of my FBO in one of my shaders so I can run some DOF equation. I am having trouble reading the buffer however.
I setup the depth texture with GL_DEPTH_STENCIL_EXT so I have the stencil value to play with too, but thats another issue for another day.
I don't how I access just the depth component of the texture from a shader (if it is possible at all?). Can I pass the the depth texture as a sampler? If anyone can help, then thanks.
For sure you can just bind the depth as a sampler. Just make sure you set your depth comparison to NONE.
Author
Huh? I don't understand.. If I set the texture as a sampler, how do i read of the first 24bits and leave out the stencil value?
Quote:Original post by idinevTo expand on that answer, you just sample the red component of the depth buffer, and you get the full 24 bit value as a float.
The texture2D() automatically gives you values in the [0;1] range. The value is (z/w+1)/2
float depth = texture2D( depthBuf, texCoords ).r;
Author
Quote:Original post by HodgmanQuote:Original post by idinevTo expand on that answer, you just sample the red component of the depth buffer, and you get the full 24 bit value as a float.
The texture2D() automatically gives you values in the [0;1] range. The value is (z/w+1)/2float depth = texture2D( depthBuf, texCoords ).r;
Awesome, I'm just on my way to work so i'll give this a blast later. If this is the case as you say, can you access the stencil value with .b?
Author
float depth = texture2D(depthImg, gl_TexCoord[0].xy).r;
this doesn't work after all. Always seems to equate to 1 :S. I can't work it out. Here is what I got to try and just output the depth as colour...
and in the c++ code...
seems like I am only getting a white screen though :(
this doesn't work after all. Always seems to equate to 1 :S. I can't work it out. Here is what I got to try and just output the depth as colour...
uniform sampler2D depthImg;void main(){ float depth = texture2D(depthImg, gl_TexCoord[0].xy).r; gl_FragColor = vec4(depth, depth, depth, 1.0);}and in the c++ code...
glActiveTexture(GL_TEXTURE0);glBindTexture(GL_TEXTURE_2D, textures[depth]);shaderDepthColour.UseProgram();RenderFullscreenQuad();seems like I am only getting a white screen though :(
Yes, it "seems"
Try this in your shader, to convert to linear:
Try this in your shader, to convert to linear:
float LinearizeDepth(float zoverw){ float n = 1.0; // camera z near float f = 20000.0; // camera z far return (2.0 * n) / (f + n - zoverw * (f - n)); }uniform sampler2D depthImg;void main(){ float depth = texture2D(depthImg, gl_TexCoord[0].xy).r; depth = LinearizeDepth(depth)*77; gl_FragColor = vec4(depth, depth, depth, 1.0);}
Author
Quote:Original post by idinev
Yes, it "seems"
Try this in your shader, to convert to linear:
*** Source Snippet Removed ***
This doesn't work either... is it potentially because I am using the wrong format for my texture?
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH24_STENCIL8_EXT, wWidth, wHeight, 0, GL_DEPTH_STENCIL_EXT, GL_UNSIGNED_INT_24_8_EXT, 0);
perhaps when using float data type in the shader the value is getting clamped because it is a 24 uint in the texture?
Hopefully you simply didn't change the "n" and "f" vars to match your persp-proj values. Also toy with the "77" value .
Or check if really the depth==1.0 :
The other stuff is: glTexParami(gl_texture_compare_mode) - has to be gl_none, otherwise the sampler will be doing shadowmap comparison (which will result in the exact problem you currently describe).
Or check if really the depth==1.0 :
float depth = texture2D(depthImg, gl_TexCoord[0].xy).r;depth = depth==1.0 ? 0 : 1; gl_FragColor = vec4(depth, depth, depth, 1.0);The other stuff is: glTexParami(gl_texture_compare_mode) - has to be gl_none, otherwise the sampler will be doing shadowmap comparison (which will result in the exact problem you currently describe).
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