9e63fb6b64
The drawing is now completely shader based, which makes away
with all usage of the depracted matrix stack. This also allows
us to do things like simple translations and texture coordinate
translation directly instead of doing everything indirectly
through matrices.
Fixed vertex attributes ('vertexPointer()' etc) are also
replaced with user defined attribute arrays.
44 lines
1.1 KiB
GLSL
44 lines
1.1 KiB
GLSL
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uniform sampler2D inputTexture;
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uniform float hueAdjust;
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varying vec2 v_texCoord;
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void main ()
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{
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const vec4 kRGBToYPrime = vec4 (0.299, 0.587, 0.114, 0.0);
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const vec4 kRGBToI = vec4 (0.596, -0.275, -0.321, 0.0);
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const vec4 kRGBToQ = vec4 (0.212, -0.523, 0.311, 0.0);
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const vec4 kYIQToR = vec4 (1.0, 0.956, 0.621, 0.0);
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const vec4 kYIQToG = vec4 (1.0, -0.272, -0.647, 0.0);
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const vec4 kYIQToB = vec4 (1.0, -1.107, 1.704, 0.0);
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/* Sample the input pixel */
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vec4 color = texture2D (inputTexture, v_texCoord.xy);
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/* Convert to YIQ */
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float YPrime = dot (color, kRGBToYPrime);
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float I = dot (color, kRGBToI);
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float Q = dot (color, kRGBToQ);
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/* Calculate the hue and chroma */
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float hue = atan (Q, I);
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float chroma = sqrt (I * I + Q * Q);
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/* Make the user's adjustments */
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hue += hueAdjust;
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// Convert back to YIQ
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Q = chroma * sin (hue);
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I = chroma * cos (hue);
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/* Convert back to RGB */
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vec4 yIQ = vec4 (YPrime, I, Q, 0.0);
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color.r = dot (yIQ, kYIQToR);
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color.g = dot (yIQ, kYIQToG);
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color.b = dot (yIQ, kYIQToB);
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/* Save the result */
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gl_FragColor = color;
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}
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