rounded-corner.glsl

float square(float val) {
    return val * val;
}
 
float distanceSquared(vec2 p1, vec2 p2) {
    vec2 vector = p2 - p1;
    return vector.x * vector.x + vector.y * vector.y;
}
 
float calcRoundedCorners() {
    if (radius <= 0.0) {
        return 1.0;
    }
    vec2 pixelPos = pass_textureCoords * vec2(uiWidth, uiHeight);
    vec2 minCorner = vec2(radius, radius);
    vec2 maxCorner = vec2(uiWidth - radius, uiHeight - radius);
 
    vec2 cornerPoint = clamp(pixelPos, minCorner, maxCorner);
    float lowerBound = square(radius - cornerSmooth);
    float upperBound = square(radius + cornerSmooth);
    return smoothstep(upperBound, lowerBound, distanceSquared(pixelPos, cornerPoint));
}