Corner radius

I couldn’t find a good simple and working shader for corner-radius anywhere so here’s what I came up with. You need to set the radius in range 0 – 1, not in pixels.

• 0 = no radius
• 1 = full circle / ellipse

Shader code

shader_type canvas_item;

uniform float corner_scale: hint_range(0., 1.) = 0.;

bool isOut(float x, float y) {
    return pow(x, 2.) + pow(y, 2.) > pow(corner_scale * .5, 2.);
}

void fragment() {
    float s = corner_scale * .5;

    if (
        (UV.x < s      && UV.y < s      && isOut(UV.x - s,      UV.y - s)) ||
        (UV.x < s      && UV.y > 1. - s && isOut(UV.x - s,      UV.y - 1. + s)) ||
        (UV.x > 1. - s && UV.y < s      && isOut(UV.x - 1. + s, UV.y - s)) ||
        (UV.x > 1. - s && UV.y > 1. - s && isOut(UV.x - 1. + s, UV.y - 1. + s))
    ) {
        COLOR.a = 0.;
    }
}

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