Black & White (sepia filter) GLSL

[devsh]

sorry for making it such a small post

but I was making a quick black and white filter and it came to me that the average method that most people would use (R+G+B)/3 is a bit too dark. So I came up with this;

fragment shader

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uniform sampler2D tex;

void main() {
   vec4 FragColor = texture2D(tex, gl_TexCoord);
   gl_FragColor = max(FragColor.r,max(FragColor.g,FragColor.b));
}

P.S. I will make a Deffered Shading and Shadowing snippet but I have to make it bug free first (problems with unbind Multiple Render Targets)

[vitek]

Why not do the normal dot(FragColor, vec3(.3, .59, .11)) to get the intensity? If you want a sepia filter, you'd use the result to do a texture lookup onto a sepia tone texture.

Travis

[jpoag]

Sepia:

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NewR = R*.393 + G*.769 + B*.189;
NewG = R*.349 + G*.686 + B*.168;
NewB = R*.272 + G*.534 + B*.131;

or presumably

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gl_FragColor.r = dot(FragColor, vec3(.393, .769, .189))
gl_FragColor.g = dot(FragColor, vec3(.349, .686, .168))
gl_FragColor.b = dot(FragColor, vec3(.272, .534, .131))