Circle Shader

Shader code
shader_type canvas_item;

uniform float amt : hint_range(0.0, 1.0);
uniform vec4 color : hint_color;

void fragment() 
{
	if (distance(UV, vec2(0.5,0.5)) > amt/2.0) 
	{
		COLOR = vec4(0.0);
	}
	else 
	{
		COLOR = vec4(color);
	}
}
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NekotoArts
NekotoArts
6 months ago

Evaluating an if statement on every fragment is generally bad practice. Try to stay away from if statements in shaders unless absolutely necessary.

For applying “boolean” operations in a shader, use the step, smoothstep, and mix functions. Here’s a more optimized version of this shader:

shader_type canvas_item;


uniform float amt : hint_range(0.0, 1.0);
uniform float edge_softness = 0.0;
uniform vec4 color : hint_color;


void fragment() 
{
	float radius = amt * 0.5;
	float d = distance(UV, vec2(0.5));
	float circle = smoothstep(d - edge_softness, d, radius - edge_softness);
	COLOR = vec4(color.rgb, circle);
}

I also added an “edge_softness” value if you want to anti-alias the edges of the circle a bit

mreliptik
mreliptik
5 months ago
Reply to  NekotoArts

Awesome work, thanks for your input Nekoto!