resources/particles/penguin_cannon.json

{
   "MaxCount": 32,
   "Duration": 1,
   "Rate": 0.5,
   "Drawable": {
      "Type": "SkImageDrawable",
      "Path": "resources/images/baby_tux.png",
      "Columns": 1,
      "Rows": 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 = 20;",
      "  float a = radians(10 + 60 * rand);",
      "  float s = 140 + rand * 60;",
      "  p.vel.x = cos(a) * s;",
      "  p.vel.y = -sin(a) * s;",
      "}",
      "",
      "void update(inout Particle p) {",
      "  p.vel.y += 50 * dt;",
      "  p.dir = normalize(p.vel);",
      "}",
      ""
   ],
   "Bindings": []
}