Hi all,
i have this problems, with my vertex shader I want the same output of standard OpenGL, but it’s very hard write all OpenGL pipeline.
Example:
if I have set in my c/c++ program this
glTexEnvfv(GL_TEXTURE_ENV,GL_TEXTURE_ENV_COLOR,f);
but I use many standard OpenGL funcs.
How can my vertex program run this code? Do I must write my code?
Is there a way easier?
Thanks and execuse me for my Englsih.
Hi,
3DLabs once proposed a free tool, which generated shader code equivalent to a given fixed function state. I could not find it anymore (broken link), but it is/was named “3DLabs ShaderGen - Fixed Functionality Shader Generation Tool”, it may be helpful.
Cheers,
Nicolas.
Edit. shadergen has been mirrored here
ok thanks but there is another way? I must change only this
vec4 col;
gl_Position = gl_Vertex; //I dont need World and View matrices
col = gl_Color;
col[3] *= 0.5;
gl_Color = col;
Agostino:
I must change only this
I’m not sure to understand what you mean.
Do you want to only have a vertex shader, using the fixed function pipeline for fragment processing ?
Does your vertex shader only do the operations you mentionned, or is it a simple example ?
A better syntax should be (untested)(I’m not familiar with vertex shader-only programs) :
void main()
{
gl_Position = gl_Vertex;
vec4 color = gl_Color;
color.z *= 0.5;
// to pass color to fixed-function fragment shader
gl_FrontColor = color;
gl_BackColor = color; // if needed ?
}
Did you have a look GLSL specification ? The “Built-in variables” chapter could give you all you need.
HTH,
Nicolas.
ok thanks i solved with 3DLabs, but now I have a new problem
float colors[20]
i = int(VertexColor.r * 20.0);
color = vec4(colors[i],colors[i+1],colors[i+2],VertexColor.a);
color = texel * color;
…and it doesnt work. ow can i fix it?
system
August 30, 2008, 11:35am
6
What does glGetShaderInfoLog return?
you dont worry i solved with sampler1d and 1 texture 1d. However it shows messages like you can use only texture coordinates or only loop etc etc . If you want more info I can replicate the bug. Thanks again
system
Closed
October 19, 2021, 7:34pm
8
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