Ring of Power

It’s a simple ring that can be used as an indicator (of an activated power, for instance). It uses a noise texture and additive blend for best result.

I recommend to use a tween or an animation player to add some dynamics.

Parameters are:

• radius : Must be in ]0, 1]. Be careful to not overshoot when add the thickness. Radius plus thickness should be less than 1.
• thickness : Must be in ]0, 1]. Thickness of the ring.
• color : Obviously, the tint of the ring.
• brightness : Color intensity multiplier.
• angular_speed : Rotation speed of the ring (in rad/s).
• radial_speed : Speed of the texture slide (in or out).
• alpha : Alpha channel override.
• noise : An seamless noise texture is preferred. But any seamless function can work (did i mention that it must be seamless ?).

Note : When using Godot 4.x, replace hint_color at line 8 with source_color. (Thx jboadas)

Shader code

shader_type canvas_item;
render_mode blend_add;

uniform float radius : hint_range(0.0, 1.0, 0.01) = .7;

uniform float thickness : hint_range(0.0, 1.0, 0.01) = .2;

uniform vec4 color : hint_color = vec4(0.9, 0.4, 0.1, 1.0);

uniform float brightness : hint_range(0.0, 15.0, 0.01) = 5.0;

uniform float angular_speed : hint_range(-5.0, 5.0, 0.01) = 2.5;

uniform float radial_speed : hint_range(-5.0, 5.0, 0.01) = 1.4;

uniform float alpha : hint_range(0.0, 1.0, 0.01) = .5;

uniform sampler2D noise;

void fragment() {
	vec2 v = vec2(.5) - UV;
	float d = length(v) * 2.;
	float angle = atan(v.y, v.x) + (TIME * angular_speed);
	float thick_ratio = 1. - (abs(d - max(0., radius)) / max(.0001, thickness));
	vec2 polar = fract(vec2(angle / 6.28, d + (TIME * radial_speed)));
	vec4 col = thick_ratio * brightness * color;
	vec3 tex = texture(noise, polar).rgb;
	col.a = (alpha * (tex.r + tex.g + tex.b) * clamp(thick_ratio, 0., 1.)) / 3.;
	COLOR = col;
}

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