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/*
Copyright (c) 2019 The Khronos Group Inc.
Use of this source code is governed by an MIT-style license that can be
found in the LICENSE.txt file.
*/
attribute vec4 gtf_Color;
attribute vec4 gtf_Vertex;
uniform mat4 gtf_ModelViewProjectionMatrix;
varying vec4 color;
void main (void)
{
const float M_PI = 3.14159265358979323846;
float c = 0.5 * M_PI * 2.0 * (gtf_Color.r - 0.5);
float o;
if(abs(c) < 0.5) // -45..45
o = 0.5 * tan(c) + 0.5;
else // 45..90, -45..-90
o = 0.5 / tan(c) + 0.5;
color = vec4(o, 0.0, 0.0, 1.0);
gl_Position = gtf_ModelViewProjectionMatrix * gtf_Vertex;
}
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