skia2/resources/particles/mouse_track.json

{
   "MaxCount": 2000,
   "Drawable": {
      "Type": "SkCircleDrawable",
      "Radius": 4
   },
   "EffectCode": [
      "uniform float2 mouse_pos;",
      "",
      "void effectSpawn(inout Effect effect) {",
      "  effect.rate = 500;",
      "}",
      "",
      "void effectUpdate(inout Effect effect) {",
      "  effect.pos = mouse_pos;",
      "}",
      ""
   ],
   "Code": [
      "void spawn(inout Particle p) {",
      "  p.lifetime = 2 + rand(p.seed);",
      "  p.vel.y = (20 * rand(p.seed)) - 10;",
      "}",
      "",
      "void update(inout Particle p) {",
      "  p.color.r = p.age;",
      "  p.color.g = 1 - p.age;",
      "  float s1 = 0.5 + (1.5 * p.age);",
      "  float s2 = 1.0 + (-0.75 * p.age);",
      "  p.scale = (s1 + (s2 - s1) * rand(p.seed)) * 0.5;",
      "  p.vel.y += 20.0 * dt;",
      "}",
      ""
   ],
   "Bindings": []
}