/// <summary>
/// Linear interpolation of two keyframe transformations.
/// </summary>
/// <param name="frame1">One keyframe</param>
/// <param name="frame2">Another keyframe</param>
/// <param name="amount">Weight of second keyframe between 0.0 and 1.0</param>
/// <returns>Interpolated transformation matrix</returns>
public static Matrix LerpTransform(JointAnimationKeyFrame frame1,
JointAnimationKeyFrame frame2, float amount)
{
// Lerp between components
Vector3 scale = Vector3.Lerp(frame1.Scale, frame2.Scale, amount);
Quaternion rotation = Quaternion.Lerp(frame1.Rotation, frame2.Rotation, amount);
Vector3 translation = Vector3.Lerp(frame1.Translation, frame2.Translation, amount);
return(Matrix.CreateScale(scale) * Matrix.CreateFromQuaternion(rotation) *
Matrix.CreateTranslation(translation));
}
/// <summary>
/// Linear interpolation of two keyframes. The resulting keyframe will consist
/// of the interpolated time and transformation.
/// </summary>
/// <param name="frame1">One keyframe</param>
/// <param name="frame2">Another keyframe</param>
/// <param name="amount">Weight of the second keyframe between 0.0 and 1.0</param>
/// <returns>Interpolated keyframe</returns>
public static JointAnimationKeyFrame Lerp(JointAnimationKeyFrame frame1,
JointAnimationKeyFrame frame2, float amount)
{
// Lerp between components
Vector3 scale = Vector3.Lerp(frame1.Scale, frame2.Scale, amount);
Quaternion rotation = Quaternion.Lerp(frame1.Rotation, frame2.Rotation, amount);
Vector3 translation = Vector3.Lerp(frame1.Translation, frame2.Translation, amount);
// Lerp time
float time = frame1.Time + (frame2.Time - frame1.Time) * amount;
return(new JointAnimationKeyFrame(time, scale, rotation, translation));
}
/// <summary>
/// Calculates a key frame at given time by interpolating between the samples
/// that are nearest (by time).
/// </summary>
/// <param name="time">Time</param>
/// <returns>Interpolated key frame for given time key</returns>
public JointAnimationKeyFrame GetInterpolatedKeyframe(float time)
{
if (time < StartTime)
{
switch (PreBehaviour)
{
case AnimationBehaviour.Constant:
time = StartTime;
break;
case AnimationBehaviour.Cycle:
time = 0;
break;
default:
// TODO: Implement other animation behaviours
throw new NotImplementedException("No animation behaviours " +
"other than Constant implemented yet");
}
}
else if (time > EndTime)
{
switch (PostBehaviour)
{
case AnimationBehaviour.Constant:
time = EndTime;
break;
case AnimationBehaviour.Cycle:
time %= EndTime;
break;
default:
// TODO: Implement other animation behaviours
throw new NotImplementedException("No animation behaviours " +
"other than Constant implemented yet");
}
}
int keyframeIndex = 0;
// Find the two frames to interpolate between
while (_keyframes[keyframeIndex].Time <= time)
{
keyframeIndex++;
}
if (keyframeIndex > 0)
{
keyframeIndex--;
}
JointAnimationKeyFrame frame1 = _keyframes[keyframeIndex];
JointAnimationKeyFrame frame2 = _keyframes[keyframeIndex + 1];
if (frame1.Time == time)
{
return(frame1);
}
switch (_interpolation)
{
case AnimationInterpolation.Linear:
float amount = 1.0f / (frame2.Time - frame1.Time) * (time - frame1.Time);
return(JointAnimationKeyFrame.Lerp(frame1, frame2, amount));
default:
// TODO: Implement other animation interpolations
throw new NotImplementedException("No animation interpolation " +
"other than Linear implemented yet");
}
}
/// <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;
}
/// <summary>
/// Imports an animation sampler.
/// Right now only LINEAR interpolation is supported, thus any other definitions
/// are simply ignored and LINEAR is used instead.
/// </summary>
/// <param name="xmlAnimation">XML animation node</param>
/// <param name="xmlSampler">XML sampler node</param>
/// <param name="target">Value of sampler's target attribute</param>
/// <returns>Animation Sampler</returns>
// TODO: Implement import of other interpolation methods than LINEAR
static JointAnimationSampler ImportSampler(XmlNode xmlAnimation, XmlNode xmlSampler,
string target)
{
// Input and Output sources
Source input = Source.FromInput(xmlSampler.SelectSingleNode("input[@semantic='INPUT']"),
xmlAnimation);
Source output = Source.FromInput(xmlSampler.SelectSingleNode("input[@semantic='OUTPUT']"),
xmlAnimation);
// Target (matrix, translation.*, rotation.*, scale.*)
target = target.Substring(target.IndexOf('/')+1);
// It is assumed that TIME is used for input
var times = input.GetData<float>();
var keyframes = new JointAnimationKeyFrame[times.Count];
if (target == "matrix")
{
// Baked matrices were used so that there is one animation per joint animating
// the whole transform matrix. Now we just need to save these transforms in keyframes
var transforms = output.GetData<Matrix>();
Debug.Assert(transforms.Count == times.Count);
for (int i = 0; i < times.Count; i++)
{
keyframes[i] = new JointAnimationKeyFrame(times[i], transforms[i]);
}
}
else if (output.DataType == typeof(float))
{
// No baked matrices, i.e. there is an animation for each component of the transform
var data = output.GetData<float>();
Debug.Assert(times.Count == data.Count);
for (int i = 0; i < times.Count; i++)
{
keyframes[i] = CreateKeyFrameFromSingle(target, data[i], times[i]);
}
}
else if (output.DataType == typeof(Vector3))
{
var data = output.GetData<Vector3>();
Debug.Assert(times.Count == data.Count);
for (int i = 0; i < times.Count; i++)
{
keyframes[i] = CreateKeyFrameFromVector(target, data[i], times[i]);
}
}
return new JointAnimationSampler(keyframes, AnimationInterpolation.Linear);
}
/// <summary>
/// Creates a new animation sampler from a list of keyframes
/// </summary>
/// <param name="keyframes">List of samples</param>
/// <param name="interpolation">Interpolation method to use</param>
public JointAnimationSampler(JointAnimationKeyFrame[] keyframes,
AnimationInterpolation interpolation)
{
_keyframes = keyframes;
_interpolation = interpolation;
if (_interpolation != AnimationInterpolation.Linear)
{
// Right now only linear interpolation is supported
_interpolation = AnimationInterpolation.Linear;
}
if (keyframes == null || keyframes.Length == 0)
{
throw new ApplicationException("Sampler needs keyframes");
}
StartTime = keyframes[0].Time;
EndTime = keyframes[keyframes.Length - 1].Time;
PostBehaviour = AnimationBehaviour.Cycle;
}
/// <summary>
/// Linear interpolation of two keyframe transformations.
/// </summary>
/// <param name="frame1">One keyframe</param>
/// <param name="frame2">Another keyframe</param>
/// <param name="amount">Weight of second keyframe between 0.0 and 1.0</param>
/// <returns>Interpolated transformation matrix</returns>
public static Matrix LerpTransform(JointAnimationKeyFrame frame1,
JointAnimationKeyFrame frame2, float amount)
{
// Lerp between components
Vector3 scale = Vector3.Lerp(frame1.Scale, frame2.Scale, amount);
Quaternion rotation = Quaternion.Lerp(frame1.Rotation, frame2.Rotation, amount);
Vector3 translation = Vector3.Lerp(frame1.Translation, frame2.Translation, amount);
return Matrix.CreateScale(scale) * Matrix.CreateFromQuaternion(rotation) *
Matrix.CreateTranslation(translation);
}
/// <summary>
/// Linear interpolation of two keyframes. The resulting keyframe will consist
/// of the interpolated time and transformation.
/// </summary>
/// <param name="frame1">One keyframe</param>
/// <param name="frame2">Another keyframe</param>
/// <param name="amount">Weight of the second keyframe between 0.0 and 1.0</param>
/// <returns>Interpolated keyframe</returns>
public static JointAnimationKeyFrame Lerp(JointAnimationKeyFrame frame1,
JointAnimationKeyFrame frame2, float amount)
{
// Lerp between components
Vector3 scale = Vector3.Lerp(frame1.Scale, frame2.Scale, amount);
Quaternion rotation = Quaternion.Lerp(frame1.Rotation, frame2.Rotation, amount);
Vector3 translation = Vector3.Lerp(frame1.Translation, frame2.Translation, amount);
// Lerp time
float time = frame1.Time + (frame2.Time - frame1.Time) * amount;
return new JointAnimationKeyFrame(time, scale, rotation, translation);
}