Hello everybody !
After working with Cg shaders, I started playing with vp 1.0.
Would anyone please give me a link to any ARB vp syntax document ?
Or anwser me this : I want to pass a sine wave value to a vertex program, i can do this one way:
multiplying original vertex coordinates by the sine value in the main code, and then send this value with glVertex to set vertex.position.
But I want to pass this sine wave value as a program variable and keep my original vertex coordinates and then multiply them in the VP.
How can i do that ?
I tried glProgramEnvParameter4fARB, but my geometry simply disapear …
Thanks in advance … !
Originally posted by raverbach:
[b]Hello everybody !
After working with Cg shaders, I started playing with vp 1.0.
Would anyone please give me a link to any ARB vp syntax document ?
Or anwser me this : I want to pass a sine wave value to a vertex program, i can do this one way:
multiplying original vertex coordinates by the sine value in the main code, and then send this value with glVertex to set vertex.position.
But I want to pass this sine wave value as a program variable and keep my original vertex coordinates and then multiply them in the VP.
How can i do that ?
I tried glProgramEnvParameter4fARB, but my geometry simply disapear …
Thanks in advance … ![/b]
First: You can find the extension spec, like for every other public extension, at OpenGL Extension Registry . It’s a very good (== complex) description of the extension.
Second: You should change your point of view regarding vertex programs. They let you do whatever you want with the variables you input. Variables input with glVertex*() don’t neccessarily need to be vertex positions. They could also be color, normal or something else. But be carefull with glColor*(), because colors (normals too?) are normalized into the range 0.0-1.0. Vertex programs are just like “fetch some variables -> do something with these values –> output the result”.
Hope this helps
You canf ind out a good tutorial on nvidia website : http://developer.nvidia.com/object/GDC_2003_Presentations.html
Look for “OpenGL ARB_vertex_program” files.
SeskaPeel.