/// <summary>
/// Creates a new joint animation channel
/// </summary>
/// <param name="sampler">Sampler</param>
/// <param name="target">Target Joint</param>
public JointAnimationChannel(JointAnimationSampler sampler, Joint target)
{
_sampler = sampler;
_target = target;
}
/// <summary>
/// Takes a group of animations which affect the same joint and combines them into
/// one animation with one channel. For this all transformations of each individual
/// keyframe are combined. Translations are added, Scales multiplied and rotations
/// multiplied as well.
/// </summary>
/// <param name="animations">List of animations</param>
/// <returns>Combined animation</returns>
static JointAnimation CombineAnimations(IEnumerable<JointAnimation> animations)
{
if (animations.Count() == 1)
{
// If there is only one animation there's no need to join
return animations.First();
}
// Number of frames that have to be combined
int numFrames = animations.First().NumFrames;
// All animations must have the same number of frames
if(!animations.All(a => a.NumFrames == numFrames))
{
throw new NotImplementedException("Animations affecting the same joint must " +
"have the same number of keyframes");
}
var combinedKeyframes = new JointAnimationKeyFrame[numFrames];
for (int i = 0; i < numFrames; i++)
{
// Create a combined key frame
float time = animations.First().Channels[0].Sampler.Keyframes[i].Time;
Vector3 scale = new Vector3(1,1,1);
Quaternion rotation = Quaternion.Identity;
Vector3 translation = new Vector3(0,0,0);
foreach (var add in animations.Select(anim => anim.Channels[0].Sampler.Keyframes[i]))
{
if (add.Scale != Vector3.One)
scale *= add.Scale;
if (add.Translation != Vector3.Zero)
translation += add.Translation;
// Single axis rotations are executed in order (as defined in the document)
// Note: Not sure if this is correct
if (add.Rotation != Quaternion.Identity)
rotation = add.Rotation * rotation;
}
var keyframe = new JointAnimationKeyFrame(time, scale, rotation, translation);
combinedKeyframes[i] = keyframe;
}
Joint target = animations.First().Channels[0].Target;
var sampler = new JointAnimationSampler(combinedKeyframes, AnimationInterpolation.Linear);
JointAnimation animation = new JointAnimation(new JointAnimationChannel[]
{
new JointAnimationChannel(sampler, target)
});
// Names
if (animations.Any(a => !String.IsNullOrEmpty(a.Name)))
{
animation.Name = animations.Where(a => !String.IsNullOrEmpty(a.Name)).
Select(a => a.Name).Aggregate((sum, name) => sum + "+" + name);
}
if (animations.Any(a => !String.IsNullOrEmpty(a.GlobalID)))
{
animation.GlobalID = animations.Where(a => !String.IsNullOrEmpty(a.GlobalID)).
Select(a => a.GlobalID).Aggregate((sum, name) => sum + "\n" + name);
}
return animation;
}