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FBO Depth

Started by jmaupay Aug 30, 2006 at 4:57 AM 1 replies 1.2k views

Original Post

Aug 30, 2006 at 4:57 AM

I have a Frame Buffer Object and I attach the DEPTH component to a texture. 1. Is the "resolution" of the frame buffer only specified by the size of the texture ? (i.e. :glTexImage2D) 2. For debug purpose, I want to see the depth texture as a grayscale texture, can I avoid a glGetTexImage or glDrawPixels and use directly the texture generated by the FBO (witout a shader) ? 3. Instead of attaching the DEPTH component to a texture, if I attach it to a RenderBuffer, can I acces to the RenderBuffer in a shader (GLSL). What are the pro/cons of rendering to a RenderBuffer anyway ?

MARS_999

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MARS_999

Aug 31, 2006 at 1:00 PM

Quote:
Original post by jmaupay
I have a Frame Buffer Object and I attach the DEPTH component to a texture.

1. Is the "resolution" of the frame buffer only specified by the size of the texture ? (i.e. :glTexImage2D)

2. For debug purpose, I want to see the depth texture as a grayscale texture, can I avoid a glGetTexImage or glDrawPixels and use directly the texture generated by the FBO (witout a shader) ?

3. Instead of attaching the DEPTH component to a texture, if I attach it to a RenderBuffer, can I acces to the RenderBuffer in a shader (GLSL). What are the pro/cons of rendering to a RenderBuffer anyway ?

1. correct

2. I am assuming you are doing shadowmapping? If so just shutdown the comparision function with GL_NONE and bind the texture object you have for depth and use it

3. I personally use a depth texture attached to a RB and not the FB... AFAIK no access to the RB with GLSL...

jmaupay

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jmaupay

Sep 1, 2006 at 12:43 AM

Thank you for your answers.

2. yes I'm trying shadowmapping. And you are right, directly using the texture with depth components is working. I wonder why I missed that solutions ? Well probably because the texture declaration: glTexImage2D(TEXTURE_2D, 0, GL_DEPTH_COMPONENT, mWidth, mHeight, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL); does'nt look like a greyscale texture, but it is.

3. Ok I'm using the texture attachment then.

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