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/*
** Copyright (c) 2012 The Khronos Group Inc.
**
** Permission is hereby granted, free of charge, to any person obtaining a
** copy of this software and/or associated documentation files (the
** "Materials"), to deal in the Materials without restriction, including
** without limitation the rights to use, copy, modify, merge, publish,
** distribute, sublicense, and/or sell copies of the Materials, and to
** permit persons to whom the Materials are furnished to do so, subject to
** the following conditions:
**
** The above copyright notice and this permission notice shall be included
** in all copies or substantial portions of the Materials.
**
** THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
** EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
** IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
** CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
** MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.
*/
#ifdef GL_ES
precision mediump float;
#endif
varying vec4 color;
void main (void)
{
const float M_PI = 3.14159265358979323846;
vec3 x = 2.0 * (color.ggg - 0.5);
vec3 y = 2.0 * (color.bbb - 0.5);
const float epsilon = 1.0e-4;
gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);
// Avoid evaluating atan(0, x) for x < epsilon because it's implementation-dependent
if(x[0] > epsilon || abs(y[0]) > epsilon)
{
gl_FragColor[0] = atan(y[0], x[0]) / (2.0 * M_PI) + 0.5;
}
if(x[1] > epsilon || abs(y[1]) > epsilon)
{
gl_FragColor[1] = atan(y[1], x[1]) / (2.0 * M_PI) + 0.5;
}
if(x[2] > epsilon || abs(y[2]) > epsilon)
{
gl_FragColor[2] = atan(y[2], x[2]) / (2.0 * M_PI) + 0.5;
}
}
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