#version 300 es

in  highp vec2 uv;
out highp vec4 color;

uniform int nv;
uniform highp float nvGain;

uniform sampler2D sampler1;
uniform sampler2D sampler2;
uniform sampler2D sampler3;

void main()
{
  highp vec4 yuv = vec4(
    texture(sampler1, uv).r,
    texture(sampler2, uv).r,
    texture(sampler3, uv).r,
    1.0
  );
  
  highp mat4 yuv_to_rgb = mat4(
    1.0,  0.0  ,  1.402, -0.701,
    1.0, -0.344, -0.714,  0.529,
    1.0,  1.772,  0.0  , -0.886,
    1.0,  1.0  ,  1.0  ,  1.0
  );
  
  color = yuv * yuv_to_rgb;
  if (nv == 1)
    color *= nvGain;
}