OpenGL ES Keyframe Animation issue

[Inaop]

Hey there, guys.

I'm having trouble with implementing keyframe animation on iPhone.

I originally based it on Jeff LaMarche's sample. In the example below I have three keyframes, it goes from the first through the second one, but then keeps going between the second and the third.

Here's the code:

if (lastKeyframeTime == 0.0) lastKeyframeTime = [NSDate     timeIntervalSinceReferenceDate];

NSTimeInterval timeSinceLastKeyFrame = [NSDate timeIntervalSinceReferenceDate] - lastKeyframeTime;

NSTimeInterval percentDone;


if (timeSinceLastKeyFrame > kAnimationDuration) {

++curFrame;
if (curFrame > numFrames-1)
curFrame = 0;

timeSinceLastKeyFrame = timeSinceLastKeyFrame - kAnimationDuration;
lastKeyframeTime = [NSDate timeIntervalSinceReferenceDate];
}

percentDone = timeSinceLastKeyFrame / kAnimationDuration;

source = animverts[curFrame];
dest = animverts[curFrame+1]; 
if ( curFrame == numFrames - 1)
dest = animverts[0];

for (int i = 0; i < (numIndices*3); i+=3) {
GLfloat diffX = dest[i] - source[i];
GLfloat diffY = dest[i+1] - source[i+1];
GLfloat diffZ = dest[i+2] - source[i+2];
curverts[i] = source[i] + (percentDone * diffX);
curverts[i+1] = source[i+1] + (percentDone * diffY);
curverts[i+2] = source[i+2] + (percentDone * diffZ);
}

then I update my VBO with curverts

What am I missing here?

[coded]

hmm I'm not an expert but I'll try to help...

umm did you indent on where its suppose to be indented?

if ( curFrame == numFrames - 1)
dest = animverts[0];

maybe you should change it to

if ( curFrame == numFrames - 1) dest = animverts[0];

Also, do you have

Jeff LaMarche's sample? Maybe it will help us to help you.

[Inaop]

I doubt indents matter, but they're fine in my XCode, it's just the way i pasted it here.

anyway here's the sample I was talking about:

iPhone Development: OpenGL ES from the Ground Up Part 9a: Fundamentals of Animation and Keyframe Animation

so like i was saying, I'm trying to make 3 frames to work now. after the last one it's supposed to start with the first frame, but for some reason gets stuck going between second and the third.