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shaders with OpenGL 1.4

Started by ehmdjii Nov 10, 2008 at 3:54 AM 6 replies 12.1k views
Original Post
ehmdjii
ehmdjii
hello, afaik OpenGL 1.4 can still do shaders, but how? for example the function glCreateShaderObjectARB is only availabel with OpenGL 2.0, right? what syntax do i need to use to get 1.4 compatibility with my shaders? thanks!
Brother Bob
Brother Bob
OpenGL 2.0 is only required for core support of shaders. If you don't have OpenGL 2.0, you have to use extensions instead (which is glCreateShaderObjectARB you mention). You need the extension present in your driver also.
V-man
V-man
glCreateShaderObjectARB is part of an extensions
http://www.opengl.org/registry/

you need
GL_ARB_shader_objects
GL_ARB_shading_language_100

and one of these at least
GL_ARB_vertex_shader
GL_ARB_fragment_shader

These were created before GL 2.0
All GPUs that support these extensions are really DX9 cards and eventually, GL 2.0 drivers were written for them.

If you have GL 1.4, then it is probably a old Radeon 8500 or Intel 950 or something like that.
ehmdjii
ehmdjii
thanks guys,
i will try and use these extensions to get it running with 1.4

Quote:
Original post by V-man
If you have GL 1.4, then it is probably a old Radeon 8500 or Intel 950 or something like that.


yes, it is an intel 950. unfortunately it seems a lot of laptop-users have this card and there are still new laptops sold with this card. that's why i want opengl 1.4 compatibility with my game. :-)

ehmdjii
ehmdjii
ok, so i found that the intel GMA 950 supports

GL_ARB_fragment_program
GL_ARB_vertex_program

but not

GL_ARB_shader_objects
GL_ARB_shading_language_100

does that make sense? what are they two above good for if you cant make shaders without the two below?

thanks!
Brother Bob
Brother Bob
GL_ARB_vertex/fragment_program is different from GL_ARB_vertex/fragment_shader. The first one is a separate, and old, shader interface. Second one is the newer you use with GL_ARB_shader_objects.
ehmdjii
ehmdjii
ah i see the difference now. thanks brother bob.

so how is it possible to get a GLSL shader running with those two extensions only?
V-man
V-man
Cg can compile GLSL code to those assembly forms (GL_ARB_fragment_program, GL_ARB_vertex_program)

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