[Fluxus] shaders on os x

[Dave Griffiths]

On Sun, 2010-01-10 at 15:52 +0000, evan.raskob [lists] wrote:
> hey gang,
> 
> has anyone got a shader working for manipulating a texture on os x  
> (gaussian blur, or enhance, or some other effect)? can i take a peek  
> at the code? having some trouble getting it to work over here and not  
> sure where the errors are.

Try these: 

---- bloom.vert.glsl -----------------------------------------------

varying vec2 texc;

void main()
{     
     // apply the normal gl modelviewprojection to the vertex
     gl_Position = gl_ModelViewProjectionMatrix*gl_Vertex;
     texc = vec2(gl_MultiTexCoord0);
}

---- bloom.frag.glsl -----------------------------------------------

varying vec2 texc; 
uniform sampler2D tex;
uniform float kernel;
uniform float scale;
uniform float thresh;

void main()
{
    vec4 sum = vec4(0);
    int i=0;

    // mess of for loops due to gpu compiler/hardware limitations
    int j=-2;
    for(i=-2; i<=2; i++) sum+=texture2D(tex,texc+vec2(i,j)*kernel);
    j=-1;
    for(i=-2; i<=2; i++) sum+=texture2D(tex,texc+vec2(i,j)*kernel);
    j=0;
    for(i=-2; i<=2; i++) sum+=texture2D(tex,texc+vec2(i,j)*kernel);
    j=1;
    for(i=-2; i<=2; i++) sum+=texture2D(tex,texc+vec2(i,j)*kernel);
    j=2;    
    for(i=-2; i<=2; i++) sum+=texture2D(tex,texc+vec2(i,j)*kernel);
    sum/=25.0;

    vec4 s=texture2D(tex, texc);
    gl_FragColor=s;

    // use the blurred colour if it's bright enough
    if (length(sum)>thresh)
    {
        gl_FragColor=sum*scale;
    }
}