#version 440

layout(location = 0) in vec2 qt_TexCoord0;
layout(location = 0) out vec4 fragColor;

layout(std140, binding = 0) uniform buf {
    mat4 qt_Matrix;
    float qt_Opacity;
    float time;
};

layout(binding = 1) uniform sampler2D source;

void main() {
    vec2 uv = qt_TexCoord0;
    
    // CRT curvature distortion
    vec2 crtUV = uv - 0.5;
    float curvature = 0.03;
    crtUV *= 1.0 + curvature * (crtUV.x * crtUV.x + crtUV.y * crtUV.y);
    crtUV += 0.5;
    
    // Clamp to avoid sampling outside
    if (crtUV.x < 0.0 || crtUV.x > 1.0 || crtUV.y < 0.0 || crtUV.y > 1.0) {
        fragColor = vec4(0.0, 0.0, 0.0, 0.0);
        return;
    }
    
    // Sample the texture
    vec4 color = texture(source, crtUV);
    
    // Scanlines effect (fine and subtle)
    float scanlineIntensity = 0.04;
    float scanline = sin(crtUV.y * 2400.0) * scanlineIntensity;
    color.rgb -= scanline;
    
    // RGB color separation (chromatic aberration)
    float aberration = 0.001;
    float r = texture(source, crtUV + vec2(aberration, 0.0)).r;
    float g = color.g;
    float b = texture(source, crtUV - vec2(aberration, 0.0)).b;
    color.rgb = vec3(r, g, b);
    
    // Subtle vignette
    float vignette = 1.0 - 0.3 * length(crtUV - 0.5);
    color.rgb *= vignette;
    
    // Slight green/cyan phosphor tint
    color.rgb *= vec3(0.95, 1.0, 0.98);
    
    // Flicker (very subtle)
    float flicker = 0.98 + 0.02 * sin(time * 15.0);
    color.rgb *= flicker;
    
    fragColor = color * qt_Opacity;
}