Circle Mask (with Feathering & Position)

Looking for a way to apply a circle mask to a Sprite3D, I couldn’t find a spatial masking shader, so I hacked one together myself.

It’s not fancy, but it get’s the job done.

Includes parameters for radius, feathering, and center position of the circle.

Instructions

Paste the code into a new ShaderMaterial for the Material Override (in Sprite3D for example). You will still need to apply a base texture to your Node.

A negative feathering value will invert the mask, which might be useful if you want to poke a hole into a texture.

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Shader code

shader_type spatial;

render_mode unshaded;

uniform sampler2D tex : source_color;  // Texture, used as color

uniform float radius = 0.3; // Radius of the circle
uniform float feather = 0.05; // Feathering of the circles edge

uniform vec2 center = vec2(0.5, 0.5); // Center (Adjust to move the circle around)

float circle_mask(vec2 _uv, vec2 _center, float _radius, float _feather) {
    float dist = length(_uv - _center); // Distance from current pixel to the center
    return smoothstep(_radius, _radius - _feather, dist); // Smooth transition
}

void fragment() {
    ALPHA = circle_mask(UV, center, radius, feather); // Use mask for transparency
    ALBEDO = texture(tex, UV).rgb;; // Set the albedo to the texture color
}

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