shader_type canvas_item;

uniform vec4 orb_color : source_color = vec4(0.2, 1.0, 0.5, 1.0); // base orb color
uniform float glow_strength : hint_range(0.0, 2.0) = 1.2;
uniform float pulse_speed : hint_range(0.0, 10.0) = 2.0;

void fragment() {
    // Centered UV (0,0 in middle, -1..1 range)
    vec2 uv = (UV - vec2(0.5)) * 2.0;
    float dist = length(uv);

    // Soft circular mask
    float circle = smoothstep(0.8, 0.0, dist);

    // Glow falloff
    float glow = smoothstep(0.5, 0.0, dist) * glow_strength;

    // Pulsing
    float pulse = 0.5 + 0.5 * sin(TIME * pulse_speed);

    vec3 color = orb_color.rgb * (circle + glow * pulse);

    COLOR = vec4(color, circle); // alpha fades at edges
}