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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.
*/
#ifdef GL_ES
precision mediump float;
#endif
varying vec4 color;
/* This epsilon will work as long as the magnitude of the float is < 128.
* This can be seen by taking the spec relative mediump precision of 2^-10:
* 0.125 / 2^-10 = 128
*/
#define ERROR_EPSILON (0.125)
void main (void)
{
mat4 a = mat4( 1.0, 2.0, 3.0, 4.0,
5.0, 6.0, 7.0, 8.0,
9.0, 10.0, 11.0, 12.0,
13.0, 14.0, 15.0, 16.0);
float gray,sum1=0.0,sum2=0.0,sum3=0.0,sum4=0.0;
int i;
sum1 += a[0][0];
sum2 += a[1][0];
sum3 += a[2][0];
sum4 += a[3][0];
sum1 += a[0][1];
sum2 += a[1][1];
sum3 += a[2][1];
sum4 += a[3][1];
sum1 += a[0][2];
sum2 += a[1][2];
sum3 += a[2][2];
sum4 += a[3][2];
sum1 += a[0][3];
sum2 += a[1][3];
sum3 += a[2][3];
sum4 += a[3][3];
if( ( sum1 > 10.0-ERROR_EPSILON && sum1 < 10.0+ERROR_EPSILON ) &&
( sum2 > 26.0-ERROR_EPSILON && sum2 < 26.0+ERROR_EPSILON) &&
( sum3 > 42.0-ERROR_EPSILON && sum3 < 42.0+ERROR_EPSILON) &&
( sum4 > 58.0-ERROR_EPSILON && sum4 < 58.0+ERROR_EPSILON) )
gray=1.0;
else gray=0.0;
gl_FragColor = vec4(gray, gray, gray, 1.0);
}
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