​

varying vec2 vTexCoord;

uniform sampler2D uIndexSource;

uniform sampler2D uPaletteSource;

uniform vec2 uSourceSize;

uniform float uScaleFactor;

uniform float uPaletteSize;

uniform float uPeriod;

uniform float uPhaseShift;

​

​

void main()

{

  vec2 pixel = vTexCoord * uSourceSize;

  float angle = 6.283185 * (pixel.x + pixel.y) / uPeriod - 6.283185 * uPhaseShift;

  float cosineTerm = (1.0 - cos(angle)) / 2.0;

  vec4 finalColor = vec4(vec3(cosineTerm), 1.0);

  gl_FragColor = finalColor;

}

​