Move particle stuff to a system to simplify spawning particles

src/bootstrap.js

@@ -14,7 +14,7 @@ game.bootstrap = (() => {
         'src/components/position.js', 'src/components/momentum.js', 'src/components/gridPosition.js',
         'src/components/appearence.js', 'src/components/controllable.js', 'src/components/pushable.js',
         'src/components/loadPriority.js', 'src/components/stop.js', 'src/components/alive.js',
-        'src/components/sprite.js'
+        'src/components/sprite.js', 'src/components/particles.js'
       ],
       id: 'components'
     },
@@ -34,7 +34,7 @@ game.bootstrap = (() => {
     { 
       src: [
         'src/systems/render.js', 'src/systems/grid.js', 'src/systems/physics.js', 'src/systems/keyboardInput.js', 
-        'src/systems/collision.js', 'src/systems/undo.js'
+        'src/systems/collision.js', 'src/systems/undo.js', 'src/systems/particle.js'
       ],
       id: 'systems' },
     { src: ['src/game.js'], id: 'game' },

src/components/particles.js

@@ -0,0 +1 @@
+game.components.Particles = (spec) => game.Component('particles', {spec});

src/entities/borderParticles.js

@@ -1,56 +1,40 @@
-game.createBorderParticles = ({colors, maxAmount, minAmount, minLife, maxLife, minRadius, maxRadius, maxSpeed}) => {
+game.createBorderParticles = () => {
-  const particles = game.Entity();
+  const particleSpawner = game.Entity();
-  let particleSpecs = Array(randomInRange(minAmount, maxAmount)).fill(0).map(() => {
+  const spawnFunction = (particleSpec) => {
-    const particle = {
-      x: Math.random(),
-      y: Math.random(),
-      dx: Math.random() * maxSpeed - maxSpeed / 2,
-      dy: Math.random() * maxSpeed - maxSpeed / 2,
-      radius: randomInRange(minRadius, maxRadius),
-      color: colors[randomInRange(0, colors.length-1)],
-      lifetime: randomInRange(minLife, maxLife),
-      elapsed: 0,
-    };
     switch (Math.floor(Math.random() * 4)) {
       case 0:
-        particle.y = 0;
+        particleSpec.y = 0;
-        particle.dy = -Math.abs(particle.dy);
+        particleSpec.dy = -Math.abs(particleSpec.dy);
         break;
       case 1:
-        particle.x = 1;
+        particleSpec.x = 1;
-        particle.dx = Math.abs(particle.dx);
+        particleSpec.dx = Math.abs(particleSpec.dx);
         break;
       case 2:
-        particle.y = 1;
+        particleSpec.y = 1;
-        particle.dy = Math.abs(particle.dy);
+        particleSpec.dy = Math.abs(particleSpec.dy);
         break;
       case 3:
-        particle.x = 0;
+        particleSpec.x = 0;
-        particle.dx = -Math.abs(particle.dx);
+        particleSpec.dx = -Math.abs(particleSpec.dx);
         break;
     }
-    return particle;
+    return particleSpec;
-  });
+  };
-  game.sprites.borderParticle = game.graphics.Sprite({
+  particleSpawner.addComponent(game.components.Particles({
-    drawFunction: (elapsedTime, {x, y, width, height}, context) => {
+    spec: {
-      particleSpecs.map((spec) => spec.elapsed += elapsedTime);
+      spawnFunction,
-      particleSpecs = particleSpecs.filter((spec) => spec.lifetime > spec.elapsed);
+      colors: ["#16f7c9", "#0d6e5a", "#2fa18a", "#48cfb4", "#58877d", "#178054", "#2cdb92"],
-      if (particleSpecs.length === 0) {
+      maxSpeed: 0.20,
-        particles.removeComponent("alive");
+      minRadius: 1,
+      maxRadius: 3,
+      minLife: 100,
+      maxLife: 300,
+      minAmount: 20,
+      maxAmount: 50,
     }
-      particleSpecs.map((spec) => {
+  }));
-        const position = {x: (spec.x * width) + x + spec.dx * spec.elapsed, y: (spec.y * height) + y + spec.dy * spec.elapsed};
+  particleSpawner.addComponent(game.components.LoadPriority({priority: 1}));
-        const fill = context.fillStyle;
+  particleSpawner.addComponent(game.components.Alive());
-        context.fillStyle = spec.color;
+  return particleSpawner;
-        context.beginPath();
-        context.arc(position.x, position.y, spec.radius, 0, 2 * Math.PI);
-        context.fill();
-        context.fillStyle = fill;
-      });
-    }
-  })
-  particles.addComponent(game.components.LoadPriority({priority: 1}));
-  particles.addComponent(game.components.Alive());
-  particles.addComponent(game.components.Sprite({spriteName: "borderParticle"}))
-  return particles;
 }

src/game.js

@@ -26,7 +26,7 @@ game.initialize = () => {
   // Maintained by gridSystem as a side-effect
   game.entitiesGrid = Array(game.config.yDim).fill(null).map(() => Array(game.config.xDim).fill(null).map(() => new Map()));
 
-  game.systemOrder = ["gridSystem", "collisionSystem", "physics", "keyboardInput", "undo", "render"];
+  game.systemOrder = ["gridSystem", "collisionSystem", "physics", "keyboardInput", "undo", "particle", "render"];
   game.systems = { };
   game.systems.physics = game.system.Physics(),
   game.systems.gridSystem = game.system.Grid(game.entitiesGrid);
@@ -34,6 +34,7 @@ game.initialize = () => {
   game.systems.render = game.system.Render(game.graphics);
   game.systems.undo = game.system.Undo(game.entitiesGrid);
   game.systems.keyboardInput = game.system.KeyboardInput(game.systems.undo);
+  game.systems.particle = game.system.Particle(game.canvas.context);
 
   lastTimeStamp = performance.now()
   requestAnimationFrame(game.loop);

src/systems/collision.js

@@ -39,19 +39,11 @@ game.system.Collision = (entitiesGrid) => {
           entity.removeComponent("momentum");
         } else {
           entitiesToPush.map((e) => {
-//            const particles = game.createBorderParticles({
+            const pushedParticleSpawner = game.createBorderParticles();
-//              colors: ["#16f7c9", "#0d6e5a", "#2fa18a", "#48cfb4", "#58877d", "#178054", "#2cdb92"],
+            pushedParticleSpawner.addComponent(game.components.Position(e.components.position));
-//              maxSpeed: 0.20,
+            pushedParticleSpawner.addComponent(game.components.Appearance({width: game.canvas.width / game.config.xDim, height: game.canvas.height / game.config.yDim}));
-//              minRadius: 1,
+            game.entities[pushedParticleSpawner.id] = pushedParticleSpawner;
-//              maxRadius: 3,
+
-//              minLife: 100,
-//              maxLife: 300,
-//              minAmount: 20,
-//              maxAmount: 50,
-//            });
-//            particles.addComponent(game.components.Position(e.components.position));
-//            particles.addComponent(game.components.Appearance({width: game.canvas.width / game.config.xDim, height: game.canvas.height / game.config.yDim}));
-//            game.entities[particles.id] = particles;
             e.addComponent(game.components.Momentum({...momentum}))
           });
         }

src/systems/particle.js

@@ -0,0 +1,57 @@
+game.system.Particle = () => {
+  "use strict"; 
+  const particleSpawners = {};
+  
+  const particleSpawner = ({colors, maxAmount, minAmount, minLife, maxLife, minRadius, maxRadius, maxSpeed, spawnFunction}) => {
+    return Array(randomInRange(minAmount, maxAmount)).fill(0).map(() => {
+      let particleSpec = {
+        x: Math.random(),
+        y: Math.random(),
+        dx: Math.random() * maxSpeed - maxSpeed / 2,
+        dy: Math.random() * maxSpeed - maxSpeed / 2,
+        radius: randomInRange(minRadius, maxRadius),
+        color: colors[randomInRange(0, colors.length-1)],
+        lifetime: randomInRange(minLife, maxLife),
+        elapsed: 0,
+      };
+      if (spawnFunction) {
+        particleSpec = {...particleSpec, ...spawnFunction(particleSpec)};
+      }
+      return particleSpec;
+    });
+  }
+
+  const update = (elapsedTime, entities, _changedIds) => {
+    for (let id in entities) {
+      const entity = entities[id];
+      if (entity.hasComponent("particles")) {
+        if (!particleSpawners[entity.id]) {
+          particleSpawners[entity.id] = particleSpawner(entity.components.particles.spec.spec);
+          entities[id].particleSprite = game.graphics.Sprite({
+            drawFunction: (elapsedTime, {x, y, width, height}, context) => {
+              let particleSpawner = particleSpawners[entity.id];
+              particleSpawner.map((particleSpec) => particleSpec.elapsed += elapsedTime);
+              particleSpawners[id] = particleSpawner.filter((particleSpec) => particleSpec.lifetime > particleSpec.elapsed);
+              particleSpawner = particleSpawners[id];
+              if (particleSpawner.length === 0) {
+                entities[id].removeComponent("alive");
+              }
+              particleSpawner.map((particleSpec) => {
+                const position = {x: (particleSpec.x * width) + x + particleSpec.dx * particleSpec.elapsed, y: (particleSpec.y * height) + y + particleSpec.dy * particleSpec.elapsed};
+                const fill = context.fillStyle;
+                context.fillStyle = particleSpec.color;
+                context.beginPath();
+                context.arc(position.x, position.y, particleSpec.radius, 0, 2 * Math.PI);
+                context.fill();
+                context.fillStyle = fill;
+              });
+            }
+          });
+        }
+      }
+    }
+    return new Set();
+  };
+
+  return { update };
+};

src/systems/render.js

@@ -10,8 +10,13 @@ game.system.Render = (graphics) => {
     });
 
     sortedEntities.forEach((entity) => {
-      if (entity.hasComponent("position") && entity.hasComponent("appearance") && entity.hasComponent("sprite")) {
+      if (entity.hasComponent("position") && entity.hasComponent("appearance")) {
-        game.sprites[entity.components.sprite.spriteName].draw(elapsedTime, {...entity.components.position, ...entity.components.appearance});
+        const drawSpec = {...entity.components.position, ...entity.components.appearance};
+        if (entity.hasComponent("sprite")) {
+          game.sprites[entity.components.sprite.spriteName].draw(elapsedTime, drawSpec);
+        } else if (entity.hasComponent("particles")) {
+          entity.particleSprite.draw(elapsedTime, drawSpec); 
+        }
       }
     });
 

styles/style.css

@@ -19,7 +19,7 @@ body {
   border: 3px solid grey;
   border-radius: 5px;
   max-width: 100%;
-  background-color: rgba(0, 0, 0, 0.95);
+  background-color: rgba(0, 0, 25, 0.9);
 }
 
 .game-hud {