Shifting triangle thing

tutorial.js

@@ -7,10 +7,69 @@ document.body.appendChild(renderer.view);
 //Create a container object called the `stage`
 var stage = new PIXI.Container();
 
-//Tell the `renderer` to `render` the `stage`
-renderer.render(stage);
-
 renderer.view.style.position = "absolute";
 renderer.view.style.display = "block";
 renderer.autoResize = true;
 renderer.resize(window.innerWidth, window.innerHeight);
+
+var counter = 0,
+    triPoints = [
+        [100, 100],
+        [50, 150],
+        [150, 150]
+    ],
+    triangle = new PIXI.Graphics();
+
+function randomInt(min, max) {
+  return Math.floor(Math.random() * (max - min + 1)) + min;
+}
+
+function drawLine(x1, y1, x2, y2) {
+    var line = new PIXI.Graphics();
+    line.lineStyle(1, 0xFFFFFF, 1);
+    line.moveTo(x1, y1);
+    line.lineTo(x2, y2);
+    line.x = x1;
+    line.y = y1;
+    stage.addChild(line);
+}
+
+function drawShiftingTriangle(triangle, arrayOfPoints) {
+    // Given arrayOfPoints, randomly shifts them by some amount, draws it, and returns new arrayOfPoints
+    var newPoints = [];
+    for (var i = 0; i < arrayOfPoints.length; i++) {
+        newPoints[i] = [arrayOfPoints[i][0] + randomInt(-10, 10),
+                        arrayOfPoints[i][1] + randomInt(-10, 10)];
+    }
+    triangle.lineStyle(4, 0xFF3300, 1);
+    triangle.beginFill(0x66FF33);
+    triangle.moveTo(newPoints[0][0], newPoints[0][1]);
+    triangle.lineTo(newPoints[1][0], newPoints[1][1]);
+    triangle.lineTo(newPoints[2][0], newPoints[2][1]);
+    triangle.lineTo(newPoints[0][0], newPoints[0][1]);
+    triangle.endFill();
+    stage.addChild(triangle);
+    
+    return newPoints;
+}
+
+function loop(){
+    requestAnimationFrame(loop);
+
+    counter += 1;
+    counter = counter % 60;
+
+    triangle.clear();
+
+    // drawLine(0, 0, counter, counter);
+    triPoints = drawShiftingTriangle(triangle, triPoints);
+
+    var mousePosition = renderer.plugins.interaction.mouse.global;
+    triangle.x = mousePosition.x;
+    triangle.y = mousePosition.y;
+
+    //Tell the `renderer` to `render` the `stage`
+    renderer.render(stage);
+}
+
+loop();