added a FPS Camera

Author: Raymond Hulha

lib/src/camera.dart

@@ -93,3 +93,83 @@ class FlyingCamera extends Animatable
     momentum.lerp( right, amount);
   }
 }
+
+class FPSCamera extends Animatable
+{
+  Camera camera;
+  Vector momentum = new Vector();
+  Vector movement = new Vector();
+  Vector tmp = new Vector();
+
+  Vector traceStart = new Vector();
+  Vector traceEnd = new Vector();
+  
+  Vector up = new Vector(0.0,0.0,1.0);
+  
+  int movementX=0;
+  int movementY=0;
+  
+  FPSCamera( this.camera) {
+
+    HTML.document.onMouseDown.listen( (HTML.MouseEvent e) {
+      e.preventDefault();
+      HTML.document.body.requestPointerLock();
+    });
+    
+    HTML.document.body.onMouseMove.listen( (HTML.MouseEvent e) {
+      e.preventDefault();
+      movementX += e.movement.x;
+      movementY += e.movement.y;
+    });
+
+  }
+  
+  void animate( double elapsed)
+  {
+    Map<int, bool> cpk = currentlyPressedKeys;
+    Map<String, bool> cpmb = currentlyPressedMouseButtons;
+    
+    movement.scale(0);
+    
+    if (cpk[Key.W] != null) {
+      movement.subtract( camera.getBack() );
+    }
+    if (cpk[Key.A] != null) {
+      movement.subtract( camera.getRight() );
+    }
+    if (cpk[Key.S] != null) {
+      movement.add( camera.getBack() );
+    }
+    if (cpk[Key.D] != null) {
+      movement.add( camera.getRight() );
+    }
+    
+    movement.z = 0.0;
+    movement.normalize();
+    momentum.add(movement);
+    tmp.set(momentum);
+    tmp.scale(0.02);
+    
+    traceStart.set(camera.getPos());
+    traceEnd.set(camera.getPos());
+    traceEnd.add(tmp);
+    
+    //Output output = level.trace( traceStart, traceEnd, 10.0);
+    //if( output.fraction == 1.0 || output.startSolid || output.allSolid )
+
+      camera.translateFromVec(tmp);
+    momentum.scale( 0.85);
+    
+    if( cpk[Key.SPACE] != null) {
+    }
+    
+    if( movementY!=0)
+      camera.matrix.rotate( movementY*0.006, camera.getRight());
+    if( movementX!=0)
+      camera.matrix.rotate( movementX*0.006, up);
+    
+    movementX=0;
+    movementY=0;
+  }
+  
+}