From 9bf384ad62915fd57a4ba194d24bed6313fc9fb5 Mon Sep 17 00:00:00 2001
From: Ian Terrell <ian.terrell@gmail.com>
Date: Tue, 19 Jul 2011 22:27:45 -0400
Subject: [PATCH] simple animations

---
 Cube/ColorfulCube.h    | 5 +++--
 Cube/ColorfulCube.m    | 6 +++++-
 Cube/CubeAppDelegate.m | 5 +++++
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/Cube/ColorfulCube.h b/Cube/ColorfulCube.h
index 3eb1435..8dc2ce2 100644
--- a/Cube/ColorfulCube.h
+++ b/Cube/ColorfulCube.h
@@ -10,11 +10,12 @@
 #import <GLKit/GLKit.h>
 
 @interface ColorfulCube : NSObject {
-  GLKVector3 position, rotation, scale;
+  GLKVector3 position, rotation, scale, rps;
 }
 
-@property GLKVector3 position, rotation, scale;
+@property GLKVector3 position, rotation, scale, rps;
 
 - (void)draw;
+- (void)updateRotations:(NSTimeInterval)dt;
 
 @end
diff --git a/Cube/ColorfulCube.m b/Cube/ColorfulCube.m
index 1a1faaf..8106018 100644
--- a/Cube/ColorfulCube.m
+++ b/Cube/ColorfulCube.m
@@ -18,7 +18,7 @@
 
 @implementation ColorfulCube
 
-@synthesize position, rotation, scale;
+@synthesize position, rotation, scale, rps;
 
 - (id)init
 {
@@ -116,4 +116,8 @@ - (void)draw
   glDisableVertexAttribArray(GLKVertexAttribColor);
 }
 
+- (void)updateRotations:(NSTimeInterval)dt {
+  rotation = GLKVector3Add(rotation, GLKVector3MultiplyScalar(rps, dt));
+}
+
 @end
diff --git a/Cube/CubeAppDelegate.m b/Cube/CubeAppDelegate.m
index 7516cd3..521b3bd 100644
--- a/Cube/CubeAppDelegate.m
+++ b/Cube/CubeAppDelegate.m
@@ -37,18 +37,23 @@ - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(
   cube.position = GLKVector3Make(0.25, 0.25, 0.0);
   cube.scale = GLKVector3Make(0.5, 0.5, 0.5);
   cube.rotation = GLKVector3Make(1.0/8*M_TAU, 1.0/8*M_TAU, 0);
+  cube.rps = GLKVector3Make(0.5, 0.4, 0.3);
   [cubes addObject:cube];
   
   ColorfulCube *cube2 = [[ColorfulCube alloc] init];
   cube2.position = GLKVector3Make(-0.5, -0.25, 0.0);
   cube2.scale = GLKVector3Make(0.4, 0.4, 0.4);
   cube2.rotation = GLKVector3Make(1.0/8*M_TAU, 0, 1.0/8*M_TAU);
+  cube2.rps = GLKVector3Make(0.3, 0.5, 0.4);
   [cubes addObject:cube2];
   
   return YES;
 }
 
 - (void)glkViewControllerUpdate:(GLKViewController *)controller {
+  NSTimeInterval dt = [controller timeSinceLastDraw];
+  for (id cube in cubes)
+    [((ColorfulCube *)cube) updateRotations:dt];
 }
 
 - (void)glkView:(GLKView *)view drawInRect:(CGRect)rect {