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
}
Tags
circle, mask, masking, sprite3D, texture
The shader code and all code snippets in this post are under CC0 license and can be used freely without the author's permission. Images and videos, and assets depicted in those, do not fall under this license. For more info, see our License terms.

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