Results 1 to 2 of 2

Thread: EXT_primitive_bounding_box : how does Primitive Generator process gl_BoundingBoxEXT[]

  1. #1
    Newbie
    Join Date
    Aug 2014
    Posts
    1

    EXT_primitive_bounding_box : how does Primitive Generator process gl_BoundingBoxEXT[]

    In the definition of Tessellation Primitive Generator, it processes gl_TessLevelOuter[] and gl_TessLevelInner[] and generates u,v,w of the relative value within [0..1]. It is not a real vertex location. How does PG process gl_BoundingBoxEXT[]? What is the function or formula related to gl_BoundingBoxEXT[]?

  2. #2
    Junior Member
    Join Date
    Sep 2014
    Posts
    2
    Note gl_BoundingBoxEXT is the output of tesselation evaluation stage (not control stage), after the tesselator. So gl_Postion-s are already known when gl_BoundingBoxEXT[] is considered.

    Regarding your question gl_BoundingBoxEXT takes clip coordinates - homogeneus x,y,z,w.
    Last edited by scygan; 09-30-2014 at 04:38 AM.

Posting Permissions

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