"If" with Vertex shader

[greg2]

If i have understood the documentations, it seems to be impossible to use "if","else"... with the ARB_Vertex_program extension (?)

Do i have to use GLSL if i want to use "if" in a vertex shader ? (using ARB extension only)

Thanks.

[dorbie]

Often you can multiply the result of a code segment by 1 or 0 where that operand is derived from the parameter you want to branch on.

[greg2]

Ok.
Thanks.

[vincoof]

Yes, when it comes about math you can emulate branching by using SGE and SLT instructions combined with things like x*1=x and x*0=0.

And if you want more advanced branching, you can take a look at the GL_NV_vertex_program2_option (only supported on NVIDIA hardware for now).