runnable fragment
code snippet
precision mediump float;
uniform vec3 uColor;
uniform float uOffset;
uniform float uMultiplier;
varying vec2 v_texcoord;
void main(){
float distanceToCenter = smoothstep(0.0, 1.0,length(v_texcoord - 0.5));
float alpha = distanceToCenter * uMultiplier + uOffset;
gl_FragColor = vec4(uColor, alpha);
}