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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 = 2.0 * M_PI * gtf_Color.r;
float sign = -1.0;
float cos_c = 1.0;
float fact = 1.0;
// Taylor-Maclaurin series expansion for cosine
for(int i = 2; i <= 20; i += 2)
{
fact *= float(i)*float(i-1);
cos_c += sign*pow(c, float(i))/fact;
sign = -sign;
}
color = vec4(0.5 * cos_c + 0.5, 0.0, 0.0, 1.0);
gl_Position = gtf_ModelViewProjectionMatrix * gtf_Vertex;
}
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