CODEWITHSUNDEEP
glsl
Patrick Cowdriver
Patrick Cowdriver

Reputation: 21

multiplying sampler lookups glsl

I pass a 1D array as sampler1D and a 2D array (basically a matrix) as sampler2D to my vertex shader. Everything works fine - i checked the values, every value is where it should be. BUT - I can't seem to multiply two values of those samplers with each other.

    float pos=0.0;
    vec4 f = texture1D(xk,ki);
    vec4 H = texture2D(er,vec2(0,i));

    pos=f[0]*H[0];
    colorcheck=pos;

I pass colorcheck to my fragment shader, but it won't render my object, instead everything is just black (passing colorcheck=1.0 works fine). I checked both vectors after the lookup - both have valid values in all fields.

I've tried f.x*H.x, and all combinations I can think of.. I even tried multiplying in the fragment shader - won't work either..

EDIT simplified vertex shader (doesnt work either/works when I pass colorcheck=1.0/f.x/H.x.. anything)

    uniform sampler1D xk;
    uniform sampler2D eigenraum;
    varying float colorcheck;
    void main(){
       vec4 f = texture1D(xk,0);
       vec4 H = texture2D(eigenraum,vec2(0,0));
       colorcheck=f[0]*H[0];
       gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
   }

and fragment shader:

varying float colorcheck;
void main()
{
    gl_FragColor=vec4(colorcheck,1,1,1.0);
}

Thanks for your help!

EDIT2 - turns out I can't substract/add them either..

Upvotes: 2

Views: 352

Answers (1)

Tim
Tim

Reputation: 35933

I found the solution - it's not in the shader code. I forgot the glActiveTexture call when binding the arrays to the textures!

Upvotes: 2

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