View Full Version : Algorithm of OpenGL tessellator

03-10-2010, 02:51 AM
Hi all,

I need to write a paper about tessellation at my university and as chapter 1 I need to describe/explain how the "standard" tessellation works. Since OpenGL is open source, I suppose also the algorithm/maths behind it are also free. Maybe it is written somewhere but I didn't find it.

Thx for any help

03-10-2010, 03:21 AM
OpenGL is not open-source. OpenGL is API specification open to anybody.
Currently tesselation in OpenGL is available only as vendor specific extension AMD_vertex_shader_tesselator (http://www.opengl.org/registry/specs/AMD/vertex_shader_tessellator.txt).

03-10-2010, 03:26 AM
Wow, thats new information :)

Do you happen to know where can I find additional information on this theme? Basically I have to describe how video cards (GPUs) display primitives (spheres,etc) using triangulation. What algorithms are used, etc. First I've thought the answer is in the Catmull-Clark subdivision surfaces, but I was pointed out that that algorithm is used for mesh refining, not for approximations with lower polycount meshes.

03-10-2010, 04:26 AM
Hardware GPUs only display triangles.
Any other primitive must be described with triangles by the CPU program.

Maybe you had something else in mind, like GLU tesselation ?

There is an open source implementation of GLU in Mesa3D: