moving the OpenGL examples to the core

java/examples/OpenGL/Performance/DynamicParticlesImmediate/DynamicParticlesImmediate.pde

@@ -0,0 +1,118 @@
+PImage sprite;  
+
+int npartTotal = 10000;
+int npartPerFrame = 25;
+float speed = 1.0;
+float gravity = 0.05;
+float partSize = 20;
+
+int partLifetime;
+PVector positions[];
+PVector velocities[];
+int lifetimes[];  
+
+int fcount, lastm;
+float frate;
+int fint = 3;
+
+void setup() {
+  size(640, 480, P3D);
+  frameRate(120);
+  
+  sprite = loadImage("sprite.png");
+
+  partLifetime = npartTotal / npartPerFrame;
+  initPositions();
+  initVelocities();
+  initLifetimes(); 
+
+  // Writing to the depth buffer is disabled to avoid rendering
+  // artifacts due to the fact that the particles are semi-transparent
+  // but not z-sorted.
+  hint(DISABLE_DEPTH_MASK);
+  
+  // Testing some hints
+  //hint(DISABLE_TRANSFORM_CACHE);
+  //hint(ENABLE_ACCURATE_2D);
+} 
+
+void draw () {
+  background(0);
+
+  for (int n = 0; n < npartTotal; n++) {
+    lifetimes[n]++;
+    if (lifetimes[n] == partLifetime) {
+      lifetimes[n] = 0;
+    }      
+
+    if (0 <= lifetimes[n]) {      
+      float opacity = 1.0 - float(lifetimes[n]) / partLifetime;
+            
+      if (lifetimes[n] == 0) {
+        // Re-spawn dead particle
+        positions[n].x = mouseX;
+        positions[n].y = mouseY;
+        
+        float angle = random(0, TWO_PI);
+        float s = random(0.5 * speed, 0.5 * speed);
+        velocities[n].x = s * cos(angle);
+        velocities[n].y = s * sin(angle);
+      } else {
+        positions[n].x += velocities[n].x;
+        positions[n].y += velocities[n].y;
+        
+        velocities[n].y += gravity;
+      }
+      drawParticle(positions[n], opacity);
+    }
+  }
+  
+  fcount += 1;
+  int m = millis();
+  if (m - lastm > 1000 * fint) {
+    frate = float(fcount) / fint;
+    fcount = 0;
+    lastm = m;
+    println("fps: " + frate); 
+  } 
+}
+
+void drawParticle(PVector center, float opacity) {
+  beginShape(QUAD);
+  noStroke();
+  tint(255, opacity * 255);
+  texture(sprite);
+  normal(0, 0, 1);
+  vertex(center.x - partSize/2, center.y - partSize/2, 0, 0);
+  vertex(center.x + partSize/2, center.y - partSize/2, sprite.width, 0);
+  vertex(center.x + partSize/2, center.y + partSize/2, sprite.width, sprite.height);
+  vertex(center.x - partSize/2, center.y + partSize/2, 0, sprite.height);                
+  endShape();  
+}
+
+void initPositions() {
+  positions = new PVector[npartTotal];
+  for (int n = 0; n < positions.length; n++) {
+    positions[n] = new PVector();
+  }  
+}
+
+void initVelocities() {
+  velocities = new PVector[npartTotal];
+  for (int n = 0; n < velocities.length; n++) {
+    velocities[n] = new PVector();
+  }
+}
+
+void initLifetimes() {
+  // Initializing particles with negative lifetimes so they are added
+  // progressively into the screen during the first frames of the sketch   
+  lifetimes = new int[npartTotal];
+  int t = -1;
+  for (int n = 0; n < lifetimes.length; n++) {    
+    if (n % npartPerFrame == 0) {
+      t++;
+    }
+    lifetimes[n] = -t;
+  }
+}