resources/particles/snowfall.json

{
   "MaxCount": 4096,
   "Duration": 1,
   "Rate": 30,
   "Drawable": {
      "Type": "SkCircleDrawable",
      "Radius": 1
   },
   "Code": [
      "// float rand; Every read returns a random float [0 .. 1)",
      "layout(ctype=float) in uniform float dt;",
      "layout(ctype=float) in uniform float effectAge;",
      "",
      "struct Particle {",
      "  float  age;",
      "  float  lifetime;",
      "  float2 pos;",
      "  float2 dir;",
      "  float  scale;",
      "  float2 vel;",
      "  float  spin;",
      "  float4 color;",
      "  float  frame;",
      "};",
      "",
      "void spawn(inout Particle p) {",
      "  p.lifetime = 10;",
      "  p.vel.y = 10 + rand * 20;",
      "  p.vel.x = -5 + 10 * rand;",
      "  p.pos.x = rand * 500;",
      "}",
      "",
      "void update(inout Particle p) {",
      "  p.scale = size(p.age);",
      "}",
      ""
   ],
   "Bindings": [
      {
         "Type": "SkCurveBinding",
         "Name": "size",
         "Curve": {
            "XValues": [],
            "Segments": [
               {
                  "Type": "Cubic",
                  "Ranged": true,
                  "Bidirectional": false,
                  "A0": 10,
                  "B0": 10,
                  "C0": 10,
                  "D0": 0,
                  "A1": 10,
                  "B1": 0,
                  "C1": 0,
                  "D1": 0
               }
            ]
         }
      }
   ]
}