nuclear@21: #version 120
nuclear@21: 
nuclear@21: void main()
nuclear@21: {
nuclear@21: 	vec2 pt = gl_PointCoord.xy * 2.0 - 1.0;
nuclear@21: 	float len = length(pt);
nuclear@21: 	vec2 dir = pt / len;
nuclear@21: 	float angle = atan(dir.y, dir.x);
nuclear@21: 
nuclear@21: 	float alpha = 1.0 - smoothstep(0.8, 0.9, len + abs(sin(angle * 8.0)) * 0.1);
nuclear@21: 	gl_FragColor = vec4(1.0, 1.0, 1.0, alpha);
nuclear@21: }