hierarchy animation

Skeleton {	SkeletonJoint joints[kMaxSkeletonJoints];	// update this from the active animation data	// these joints are the characters "rig", properly parented, indexable by the weight/joint index, 	// with root at index [0], and all children  at some index > 0}

SkeletonJoint {	SkeletonJoint* parent;		// parent == NULL, root joint, begin updating from there	SkeletonJoint* children[kMaxChildJoints]		// animation creates these from animating the skeleton, generating interpolated versions of these	vec3 local_pos;	vec3 local_scale;	quat local_rot;	// this.world_ = parent.world_ combined with  this.local_ 	vec3 world_pos;	vec3 world_scale;	quat world_rot;	Mat4 finalWorldMatrix;	// computed by combining world_ parts		Mat4 invBindPoseMatrix;	// from file, usually part of skinning info	Mat4 skinMatrix;	// updated each frame, skinMatrix = finalWorldMatrix * invBindMatrix	Update()	// make sure this is called from root joint down, parent == NULL	{		if(parent)	// should be updated first		{			vec3 parentWorldPos = parent->world_pos;						vec3 parentWorldScale = parent->world_scale;			vec3 parentWorldRot = parent->world_rot;			this->world_rot = parentWorldRot * this->local_rot;			this->world_pos = (parentWorldRot * (this->local_pos * parentWorldScale)) + parentWorldPos			this->world_scale = parentWorldScale * this->local_scale		}		else		{			world_pos = local_pos;			world_scale = local_scale;			world_rot = local_rot;				}		mat3 rm = world_rot.ToRotationMatrix();		mat3 sm = FromScale(world_scale)		finalWorld = Mat4FromMat3AndT(rm * sm, world_pos)		skinMatrix = finalWorld * invBindPoseMatrix	}}

JointPose {	vec3 pos;	vec3 scale;	quat rot;}SkeletonPose {	Array<JointPose> joints;	// frozen animation start pose, from animation file, variable length, animations dont always change every joint}Animation {	float currentTime		// add deltaTime to this to advance the animation	SkeletonPose basePose;		// animate all or some of these to where it should be based on "currentTime"	AnimationChannel channels[?];	// sometimes called tracks}

SkeletonResultPose {	JointPose jointPose[kMaxSkeletonJoints];	// result of animating}Skeleton::Update(float dt){	SkeletonResultPose result;	// the skeleton for this frame time of the active animation	activeAnimation->Update(dt, result)	{		result = basePose;	// copy base, start with the base pose, all or some of it is replaced by channel data		currentTime += dt;	// advance the animation		activeAnimation->ComputeFromChannels(currentTime, result)	// change parts of the result (base) or all		{			FOR EACH CHANNEL	// could be as much as num skeleton joints * 3 (rot, tran, scale) i suppose				Channel* ch = this->channels;				index = ch->targetIndex;	// channels data targets some joint				// change these				vec3& t = result.jointPose[index].pos;				quat& r = result.jointPose[index].rot;				vec3& s = result.jointPose[index].scale;								ch->Update(currentTime, r, t, s)				{					// channel generates interpoalted rotation, translation or scale, channel knows, we dont					// pass all 3, it modifies which ever it targets					// Example: determine interpolated "t" at "currentTime (0.5)"					{						// find previous key frame number							// from sample channel time data						FOR EACH TIME SAMPLE (i = 0; i < numKeyTime - 1; ++i)							if(time >= keyTime && time < keyTime[i + 1])								return i;	// prevFrame						// nextFrame index = prevFrame index + 1						// got frame before and after time (0.5), now interpolate						t =  // interpolated value between data[prevFrame] and data[nextFrame]						// channel may just change t.x or s.z, usually all of r, but replaces something					}										// or r					// or s				}						}	}	// now we have an resulting skeleton pose created by animation in "result"	// optional: gen another skeleton pose from another animation, blend them, creating a third pose	// update the local of the final skeleton using "result" from active animation	FOR EACH JOINT 	// simply copy result to final skeleton local		this->joints.local_pos = result.jointPose.pos;		this->joints.local_scale = result.jointPose.scale;		this->joints.local_rot = result.jointPose.rot;	// compute the matrices from the resulting pieces	FOR EACH JOINT  // see above		this->joints.Update()	// gen finalWorld, build new skinMatrix from it	// do skinning with joints.skinMatrix and wight}