fixed an issue where mouse attract vec was updated before a user inte…

…racted

alphaBlended3DParticles.pde

@@ -2,14 +2,15 @@ Particle p[];
 float fadeRate;
 int numParticles = 50;
 PVector mouseAttractVec;
+boolean userHasInteracted = false;
 
 void setup() {
   size(500, 500);
   background(0);
   smooth();
   noStroke();
   frameRate(30);
-  mouseAttractVec = new PVector(1.0f, 1.0f, 1.0f);
+  mouseAttractVec = new PVector(0.0f, 0.0f, 0.0f);
 
   fadeRate = 15.0f;
   p = new Particle[numParticles];
@@ -21,18 +22,37 @@ void setup() {
 
 void draw() {
 
-  if (frameCount % (int) (frameRate / 4) == 0) {
-    mouseAttractVec = getMouseAttractVec();
+  if (frameCount == 0) {
+    mouseAttractVec = new PVector(0.0f, 0.0f, 0.0f);
   }
 
+  if (userHasInteracted && (frameCount % (int) (frameRate / 4) == 0)) {
+      mouseAttractVec = getMouseAttractVec();
+  }
   background(0);
   updateParticles(p);
 }
 
+void mouseMoved() {
+  userHasInteracted = true;
+}
+
+void mousePressed() {
+  userHasInteracted = true;
+}
+
 PVector getMouseAttractVec() {
+    //for some reason, processing sets the mouseX 
+    //and mouseY to upper left corner. Detecting 
+    //and correcting. Assuming user can never get a
+    //mouseX, mouseY of (0, 0);
+    if (mouseX == 0 && mouseY == 0) {
+      println("were both 0 on frame " + frameCount);
+    }
+
     float newXVal = map(mouseX, 0, width, -1, 1);
     float newYVal = map(mouseY, 0, height, -1, 1);
-
+      
     return new PVector(newXVal, newYVal, 0.0f);
 }
 

applet_js/alphaBlended3DParticles.pde

@@ -1,13 +1,15 @@
 Particle p[];
 float fadeRate;
 int numParticles = 50;
+PVector mouseAttractVec;
 
 void setup() {
   size(500, 500);
   background(0);
   smooth();
   noStroke();
   frameRate(30);
+  mouseAttractVec = new PVector(1.0f, 1.0f, 1.0f);
 
   fadeRate = 15.0f;
   p = new Particle[numParticles];
@@ -18,8 +20,20 @@ void setup() {
 }
 
 void draw() {
+
+  if (frameCount % (int) (frameRate / 4) == 0) {
+    mouseAttractVec = getMouseAttractVec();
+  }
+
   background(0);
-  updateParticles(p);  
+  updateParticles(p);
+}
+
+PVector getMouseAttractVec() {
+    float newXVal = map(mouseX, 0, width, -1, 1);
+    float newYVal = map(mouseY, 0, height, -1, 1);
+
+    return new PVector(newXVal, newYVal, 0.0f);
 }
 
 void updateParticles(Particle _p[]) {
@@ -44,6 +58,8 @@ class Particle {
   int life = 0;
   float zScalar = 0.9; //for determining how the z axis is graphically interpreted
   float curPartSize;
+  float innerRingMultiplier;
+  boolean allowAttraction = true;
 
   Particle() {
 
@@ -53,6 +69,7 @@ class Particle {
     velocity.mult(random(minMagnitude, maxMagnitude));
     partSize = random(30, 60);
     curPartSize = partSize;
+    innerRingMultiplier = random(0.2, 5);
   }
 
   void render() {
@@ -63,7 +80,7 @@ class Particle {
     for (int i = 0; i < numInnerRings; i++) {
       float curWhiteVal = map(i, 0, numInnerRings - 1, 0, 255);
       float curAlpha = map(i, 0, numInnerRings - 1, 20, 200);
-      float ringSize = curPartSize / (i * 2.0f + 1.0f);
+      float ringSize = curPartSize / (i * innerRingMultiplier + 1.0f);
 
       fill(curWhiteVal, curWhiteVal, 255, curAlpha);
       ellipse(position.x, position.y, ringSize, ringSize);
@@ -101,6 +118,17 @@ class Particle {
   }
 
   void move() {
+    if (allowAttraction) {
+      float attractionAmount;
+      PVector localMouseAttract = mouseAttractVec.get();
+      localMouseAttract.mult(0.08);
+
+      float curMagnitude = velocity.mag();
+      velocity.add(localMouseAttract);
+      velocity.normalize();
+      velocity.mult(curMagnitude);
+    } 
+
     position.add(velocity);
   }