#version 450

layout(location = 0) in vec3 fragColor;
layout(location = 1) in vec3 fragLineStart;
layout(location = 2) in vec3 fragLineEnd;

layout(location = 0) out vec4 outColor;

void main() {
    vec2 fragPos = gl_FragCoord.xy;
    
    vec2 start = (fragLineStart.xy * 0.5 + 0.5) * 480.0;
    vec2 end = (fragLineEnd.xy * 0.5 + 0.5) * 480.0;
    
    vec2 lineDir = end - start;
    float lineLength = length(lineDir);
    
    if (lineLength < 1.0) {
        outColor = vec4(fragColor, 1.0);
        return;
    }
    
    lineDir = normalize(lineDir);
    vec2 toFrag = fragPos - start;
    float projection = dot(toFrag, lineDir);
    projection = clamp(projection, 0.0, lineLength);
    
    vec2 closestPoint = start + lineDir * projection;
    float distanceToLine = length(fragPos - closestPoint);
    
    float lineWidth = 6.0;
    
    if (distanceToLine > lineWidth) {
        discard;
    }
    
    float dashLength = 50.0;  
    float gapLength = 20.0;   
    
    float patternLength = dashLength + gapLength;
    float patternPos = mod(projection, patternLength);
    
    if (patternPos > dashLength) {
        discard;
    }
    
    outColor = vec4(fragColor, 1.0);
}