skia2/resources/particles/mouse_trail.json

{
   "MaxCount": 2000,
   "Drawable": {
      "Type": "SkCircleDrawable",
      "Radius": 4
   },
   "EffectCode": [
      "void effectSpawn(inout Effect effect) {",
      "  effect.rate = 800;",
      "}",
      ""
   ],
   "Code": [
      "void spawn(inout Particle p) {",
      "  p.lifetime = 2 + rand(p.seed);",
      "  float a = radians(rand(p.seed) * 360);",
      "  p.vel = float2(cos(a), sin(a)) * mix(5, 15, rand(p.seed));",
      "  p.scale = mix(0.25, 0.75, rand(p.seed));",
      "}",
      "",
      "void update(inout Particle p) {",
      "  p.color.r = p.age;",
      "  p.color.g = 1 - p.age;",
      "}",
      ""
   ],
   "Bindings": []
}