new PShape examples

java/examples/Topics/Create Shapes/ParticleSystemPShape/Particle.pde

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+// An individual Particle
+
+class Particle {
+
+  // Velocity
+  PVector velocity;
+  // Lifespane is tied to alpha
+  float lifespan;
+
+  // The particle PShape
+  PShape part;
+  // The particle size
+  float partSize;
+
+  // A single force
+  PVector gravity = new PVector(0, 0.1);
+
+  Particle() {
+    partSize = random(10, 60);
+    // The particle is a textured quad
+    part = createShape(QUAD);
+    part.noStroke();
+    part.texture(sprite);
+    part.normal(0, 0, 1);
+    part.vertex(-partSize/2, -partSize/2, 0, 0);
+    part.vertex(+partSize/2, -partSize/2, sprite.width, 0);
+    part.vertex(+partSize/2, +partSize/2, sprite.width, sprite.height);
+    part.vertex(-partSize/2, +partSize/2, 0, sprite.height);
+    part.end();
+
+    // Set the particle starting location
+    rebirth(width/2, height/2);
+  }
+
+  PShape getShape() {
+    return part;
+  }
+
+  void rebirth(float x, float y) {
+    float a = random(TWO_PI);
+    float speed = random(0.5, 4);
+    // A velocity with random angle and magnitude
+    velocity = PVector.fromAngle(a);
+    velocity.mult(speed);
+    // Set lifespan
+    lifespan = 255;
+    // Set location using translate
+    PVector center = part.getCenter();
+    part.translate(x - center.x, y - center.y);
+  }
+
+  // Is it off the screen?
+  boolean isDead() {
+    PVector center = part.getCenter();
+    if (center.y > height+50) {
+      return true;
+    } 
+    else {
+      return false;
+    }
+  }
+
+  void update() {
+    // Decrease life
+    lifespan = lifespan - 4;
+    // Apply gravity
+    velocity.add(gravity);
+    part.tint(255, lifespan);
+    // Move the particle according to its velocity
+    part.translate(velocity.x, velocity.y);
+  }
+}
+