fragment.glsl

// fragment.glsl
#version 400

uniform usampler2D yuvTexture;

in vec4 texcoord;

out vec4 frag_color;

const mat3 HDTV = mat3(1.0,    1.0,   1.0,
                       0.0,   -0.187, 1.856,
                       1.575, -0.468, 0.0);

// Constants needed to extract YUV planes from the texture
const float YHeight = 2.0 / 3.0;
const float UHeight = 1.0 / 6.0;
const float VHeight = UHeight;
const float UOffset = YHeight;
const float VOffset = UOffset + UHeight;

void main()
{
    // Extract the YUV planes from texture
    float y = (float(texture(yuvTexture, vec2(texcoord.s, texcoord.t * YHeight)).r) - 64) / 876.0;
    float u = (float(texture(yuvTexture, vec2(texcoord.s / 2, UOffset + texcoord.t * UHeight)).r) - 512) / 896.0;
    float v = (float(texture(yuvTexture, vec2(texcoord.s / 2, VOffset + texcoord.t * VHeight)).r) - 512) / 896.0;

    frag_color = vec4(HDTV * vec3(y, u, v), 1.0);
    //frag_color = vec4(texcoord.stp, 1.0);
}