Fragment Shader
[c]
uniform sampler2D image;
uniform sampler3D lookup;
uniform float imageWidth;
uniform float imageHeight;
varying vec2 pos;

void main(void)
{
//find the texture coordinate corresponding to this fragment
vec2 texCoord = vec2(pos.x/imageWidth, pos.y/imageHeight);

//get the corresponding color
vec4 colorIn = texture2D(image, texCoord);

//apply look up tables
vec4 colorOut;
colorOut.rgb = texture3D(lookup, colorIn.rgb).rgb;

//final color
gl_FragColor = colorOut;
}
[/c]

Multitexturing
[c]
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, imageName);

glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_3D, lutName);
[/c]

Set Texture in Shader Program
[c]
texLoc = glGetUniformLocation(programObj, “image”);
glUniform1i(texLoc, 0); //texture0
texLoc = glGetUniformLocation(programObj, “lookup”);
glUniform1i(texLoc, 1); //texture1
[/c]

Note:

• Test in orthographic mode is more easier
• Easy GLUT base code
• Easy GLSL wrapper
• Good OpenGL book RedBook and OrangeBook