Part of the Khronos Group
OpenGL.org

The Industry's Foundation for High Performance Graphics

from games to virtual reality, mobile phones to supercomputers

Results 1 to 5 of 5

Thread: accessing frame buffer

  1. #1
    Junior Member Regular Contributor
    Join Date
    Jan 2002
    Location
    France
    Posts
    129

    accessing frame buffer

    I did not seen any built in variable to access currently rendered pixel color and depth - I mean not the currently processed pixel but already processed pixel, available in the frame buffer (in case of a multipasse rendering).
    What I'm talking about would be a kind of gl_FragColor or gl_FragDepth but giving current frame buffer color and depth for the current pixel processed. Do you know how to access it ?

  2. #2
    Member Regular Contributor
    Join Date
    Apr 2002
    Location
    Austria
    Posts
    328

    Re: accessing frame buffer

    Right now there's no possibility to access the frame buffer. If you use multipass techniques you have to use textures right now.
    There is a theory which states that if ever anybody discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable.

    There is another theory which states that this has already happened...

  3. #3
    Junior Member Newbie
    Join Date
    Apr 2005
    Posts
    15

    Re: accessing frame buffer

    Long time your posts are ago. So, is there now a possibility to access the framebuffer like you said in the topic??

    thx

  4. #4
    Junior Member Regular Contributor
    Join Date
    Dec 2002
    Location
    Silicon Valley
    Posts
    218

    Re: accessing frame buffer

    I believe this issue was considered a long time ago when they were designing GLSL. They talked about having built-in variables gl_FBColor, gl_FBDepth, and gl_FBStencil. From what I've read, they decided against these variables because they would be impractical to implement and have poor performance.

    Have a look at issues 7 and 23 at the bottom of the GLSL spec. http://oss.sgi.com/projects/ogl-samp...ll.1.10.59.pdf

  5. #5
    Junior Member Newbie
    Join Date
    Apr 2005
    Posts
    15

    Re: accessing frame buffer

    Alright, then I have to find a different solution.

    Thanx anyway

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •