update VR ray casting examples

Author: codeanticode

mode/libraries/vr/examples/GenerateRay/GenerateRay.pde

@@ -1,7 +1,9 @@
 import processing.vr.*;
 
+PVector origin, direction;
 float[] randomx = new float[5];
 float[] randomy = new float[5];
+float[] randomz = new float[5];
 VRCamera cam;
 
 void setup() {
@@ -10,30 +12,45 @@ void setup() {
   cam = new VRCamera(this);
 
   for (int i = 0; i < 5; ++i) {
-    randomx[i] = random(-500, 500);
-    randomy[i] = random(-500, 500);
+     randomx[i] = random(-500, 500);
+     randomy[i] = random(-500, 500);
+    randomz[i] = random(-100, 100);
   }
+  noStroke();
+
+  origin = new PVector(randomx[0], randomy[0], randomz[0]);
+  direction = new PVector();
 }
 
 void draw() {
   background(200, 0, 150);
+  lights();
 
   cam.setPosition(0, 0, 400);
   push();
-  translate(randomx[0], randomy[0]);
+  translate(randomx[0], randomy[0], randomz[0]);
   fill(0, 255, 0);
   sphere(30);
-  rotateZ(millis() / 1000);
-  line(0, 0, 0, 1000, 1000, 0);
-  PVector origin = new PVector(0, 0, 0);
-  PVector dest = new PVector(1000, 1000, 0);
+
+  int r = floor(random(1, 5));
+  float rx = randomx[r] - randomx[0];
+  float ry = randomy[r] - randomy[0];
+  float rz = randomz[r] - randomz[0];
+  stroke(0);
+  strokeWeight(1 * displayDensity);
+  line(0, 0, 0, rx, ry, rz);
+  noStroke();
+
+  direction.set(rx, ry, rz);
+  direction.normalize();
 
   pop();
+
   for (int i = 1; i < 5; ++i) {
     push();
-    translate(randomx[i], randomy[i]);
+    translate(randomx[i], randomy[i], randomz[i]);
     fill(255, 0, 0);
-    if (intersectsSphere(70, origin, dest)) {
+    if (intersectsSphere(70, origin, direction)) {
       fill(0, 0, 255);
     }
     sphere(70);

mode/libraries/vr/src/processing/vr/VRCamera.java

@@ -23,10 +23,12 @@
 package processing.vr;
 
 import processing.core.PApplet;
+import processing.core.PVector;
 
 public class VRCamera {
   protected PApplet parent;
   protected VRGraphics graphics;
+  protected PVector pos = new PVector();
 
   public VRCamera(PApplet parent) {
     if (parent.g instanceof VRGraphics) {
@@ -47,7 +49,14 @@ public void noSticky() {
   }
 
   public void setPosition(float x, float y, float z) {
-    graphics.translate(-x, -y, -z);
+    if (pos.x != x || pos.y != y || pos.z != z) {
+      graphics.beginCamera();
+      // Eliminate previous position from matrix stack by applying inverse transformation.
+      graphics.translate(-pos.x, -pos.y, -pos.z);
+      pos.set(-x, -y, -z);
+      graphics.translate(pos.x, pos.y, pos.z);
+      graphics.endCamera();
+    }
   }
 
   public void setNear(float near) {