// Copyright (C) 2002-2012 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h

#include "CSkinnedMesh.h"
#include <optional>
#include "CBoneSceneNode.h"
#include "IAnimatedMeshSceneNode.h"
#include "os.h"

namespace
{
// Frames must always be increasing, so we remove objects where this isn't the case
// return number of kicked keys
template <class T> // T = objects containing a "frame" variable
irr::u32 dropBadKeys(irr::core::array<T> &array)
{
	if (array.size() < 2)
		return 0;

	irr::u32 n = 1; // new index
	for (irr::u32 j = 1; j < array.size(); ++j) {
		if (array[j].frame < array[n - 1].frame)
			continue; // bad frame, unneeded and may cause problems
		if (n != j)
			array[n] = array[j];
		++n;
	}
	irr::u32 d = array.size() - n; // remove already copied keys
	if (d > 0) {
		array.erase(n, d);
	}
	return d;
}

// drop identical middle keys - we only need the first and last
// return number of kicked keys
template <class T, typename Cmp> // Cmp = comparison for keys of type T
irr::u32 dropMiddleKeys(irr::core::array<T> &array, Cmp &cmp)
{
	if (array.size() < 3)
		return 0;

	irr::u32 s = 0; // old index for current key
	irr::u32 n = 1; // new index for next key
	for (irr::u32 j = 1; j < array.size(); ++j) {
		if (cmp(array[j], array[s]))
			continue; // same key, handle later

		if (j > s + 1)                 // had there been identical keys?
			array[n++] = array[j - 1]; // keep the last
		array[n++] = array[j];         // keep the new one
		s = j;
	}
	if (array.size() > s + 1)                 // identical keys at the array end?
		array[n++] = array[array.size() - 1]; // keep the last

	irr::u32 d = array.size() - n; // remove already copied keys
	if (d > 0) {
		array.erase(n, d);
	}
	return d;
}

bool identicalPos(const irr::scene::ISkinnedMesh::SPositionKey &a, const irr::scene::ISkinnedMesh::SPositionKey &b)
{
	return a.position == b.position;
}

bool identicalScale(const irr::scene::ISkinnedMesh::SScaleKey &a, const irr::scene::ISkinnedMesh::SScaleKey &b)
{
	return a.scale == b.scale;
}

bool identicalRotation(const irr::scene::ISkinnedMesh::SRotationKey &a, const irr::scene::ISkinnedMesh::SRotationKey &b)
{
	return a.rotation == b.rotation;
}
}

namespace irr
{
namespace scene
{

//! constructor
CSkinnedMesh::CSkinnedMesh() :
		SkinningBuffers(0), EndFrame(0.f), FramesPerSecond(25.f),
		LastAnimatedFrame(-1), SkinnedLastFrame(false),
		InterpolationMode(EIM_LINEAR),
		HasAnimation(false), PreparedForSkinning(false),
		AnimateNormals(true), HardwareSkinning(false)
{
#ifdef _DEBUG
	setDebugName("CSkinnedMesh");
#endif

	SkinningBuffers = &LocalBuffers;
}

//! destructor
CSkinnedMesh::~CSkinnedMesh()
{
	for (u32 i = 0; i < AllJoints.size(); ++i)
		delete AllJoints[i];

	for (u32 j = 0; j < LocalBuffers.size(); ++j) {
		if (LocalBuffers[j])
			LocalBuffers[j]->drop();
	}
}

//! returns the amount of frames in milliseconds.
//! If the amount is 1, it is a static (=non animated) mesh.
u32 CSkinnedMesh::getFrameCount() const
{
	return core::floor32(EndFrame + 1.f);
}

//! Gets the default animation speed of the animated mesh.
/** \return Amount of frames per second. If the amount is 0, it is a static, non animated mesh. */
f32 CSkinnedMesh::getAnimationSpeed() const
{
	return FramesPerSecond;
}

//! Gets the frame count of the animated mesh.
/** \param fps Frames per second to play the animation with. If the amount is 0, it is not animated.
The actual speed is set in the scene node the mesh is instantiated in.*/
void CSkinnedMesh::setAnimationSpeed(f32 fps)
{
	FramesPerSecond = fps;
}

//! returns the animated mesh based on a detail level. 0 is the lowest, 255 the highest detail. Note, that some Meshes will ignore the detail level.
IMesh *CSkinnedMesh::getMesh(s32 frame, s32 detailLevel, s32 startFrameLoop, s32 endFrameLoop)
{
	// animate(frame,startFrameLoop, endFrameLoop);
	if (frame == -1)
		return this;

	animateMesh((f32)frame, 1.0f);
	skinMesh();
	return this;
}

//--------------------------------------------------------------------------
//			Keyframe Animation
//--------------------------------------------------------------------------

//! Animates this mesh's joints based on frame input
//! blend: {0-old position, 1-New position}
void CSkinnedMesh::animateMesh(f32 frame, f32 blend)
{
	if (!HasAnimation || LastAnimatedFrame == frame)
		return;

	LastAnimatedFrame = frame;
	SkinnedLastFrame = false;

	if (blend <= 0.f)
		return; // No need to animate

	for (u32 i = 0; i < AllJoints.size(); ++i) {
		// The joints can be animated here with no input from their
		// parents, but for setAnimationMode extra checks are needed
		// to their parents
		SJoint *joint = AllJoints[i];

		const core::vector3df oldPosition = joint->Animatedposition;
		const core::vector3df oldScale = joint->Animatedscale;
		const core::quaternion oldRotation = joint->Animatedrotation;

		core::vector3df position = oldPosition;
		core::vector3df scale = oldScale;
		core::quaternion rotation = oldRotation;

		getFrameData(frame, joint,
				position, joint->positionHint,
				scale, joint->scaleHint,
				rotation, joint->rotationHint);

		if (blend == 1.0f) {
			// No blending needed
			joint->Animatedposition = position;
			joint->Animatedscale = scale;
			joint->Animatedrotation = rotation;
		} else {
			// Blend animation
			joint->Animatedposition = core::lerp(oldPosition, position, blend);
			joint->Animatedscale = core::lerp(oldScale, scale, blend);
			joint->Animatedrotation.slerp(oldRotation, rotation, blend);
		}
	}

	// Note:
	// LocalAnimatedMatrix needs to be built at some point, but this function may be called lots of times for
	// one render (to play two animations at the same time) LocalAnimatedMatrix only needs to be built once.
	// a call to buildAllLocalAnimatedMatrices is needed before skinning the mesh, and before the user gets the joints to move

	//----------------
	// Temp!
	buildAllLocalAnimatedMatrices();
	//-----------------

	updateBoundingBox();
}

void CSkinnedMesh::buildAllLocalAnimatedMatrices()
{
	for (u32 i = 0; i < AllJoints.size(); ++i) {
		SJoint *joint = AllJoints[i];

		// Could be faster:

		if (joint->UseAnimationFrom &&
				(joint->UseAnimationFrom->PositionKeys.size() ||
						joint->UseAnimationFrom->ScaleKeys.size() ||
						joint->UseAnimationFrom->RotationKeys.size())) {
			joint->GlobalSkinningSpace = false;

			// IRR_TEST_BROKEN_QUATERNION_USE: TODO - switched to getMatrix_transposed instead of getMatrix for downward compatibility.
			//								   Not tested so far if this was correct or wrong before quaternion fix!
			joint->Animatedrotation.getMatrix_transposed(joint->LocalAnimatedMatrix);

			// --- joint->LocalAnimatedMatrix *= joint->Animatedrotation.getMatrix() ---
			f32 *m1 = joint->LocalAnimatedMatrix.pointer();
			core::vector3df &Pos = joint->Animatedposition;
			m1[0] += Pos.X * m1[3];
			m1[1] += Pos.Y * m1[3];
			m1[2] += Pos.Z * m1[3];
			m1[4] += Pos.X * m1[7];
			m1[5] += Pos.Y * m1[7];
			m1[6] += Pos.Z * m1[7];
			m1[8] += Pos.X * m1[11];
			m1[9] += Pos.Y * m1[11];
			m1[10] += Pos.Z * m1[11];
			m1[12] += Pos.X * m1[15];
			m1[13] += Pos.Y * m1[15];
			m1[14] += Pos.Z * m1[15];
			// -----------------------------------

			if (joint->ScaleKeys.size()) {
				/*
				core::matrix4 scaleMatrix;
				scaleMatrix.setScale(joint->Animatedscale);
				joint->LocalAnimatedMatrix *= scaleMatrix;
				*/

				// -------- joint->LocalAnimatedMatrix *= scaleMatrix -----------------
				core::matrix4 &mat = joint->LocalAnimatedMatrix;
				mat[0] *= joint->Animatedscale.X;
				mat[1] *= joint->Animatedscale.X;
				mat[2] *= joint->Animatedscale.X;
				mat[3] *= joint->Animatedscale.X;
				mat[4] *= joint->Animatedscale.Y;
				mat[5] *= joint->Animatedscale.Y;
				mat[6] *= joint->Animatedscale.Y;
				mat[7] *= joint->Animatedscale.Y;
				mat[8] *= joint->Animatedscale.Z;
				mat[9] *= joint->Animatedscale.Z;
				mat[10] *= joint->Animatedscale.Z;
				mat[11] *= joint->Animatedscale.Z;
				// -----------------------------------
			}
		} else {
			joint->LocalAnimatedMatrix = joint->LocalMatrix;
		}
	}
	SkinnedLastFrame = false;
}

void CSkinnedMesh::buildAllGlobalAnimatedMatrices(SJoint *joint, SJoint *parentJoint)
{
	if (!joint) {
		for (u32 i = 0; i < RootJoints.size(); ++i)
			buildAllGlobalAnimatedMatrices(RootJoints[i], 0);
		return;
	} else {
		// Find global matrix...
		if (!parentJoint || joint->GlobalSkinningSpace)
			joint->GlobalAnimatedMatrix = joint->LocalAnimatedMatrix;
		else
			joint->GlobalAnimatedMatrix = parentJoint->GlobalAnimatedMatrix * joint->LocalAnimatedMatrix;
	}

	for (u32 j = 0; j < joint->Children.size(); ++j)
		buildAllGlobalAnimatedMatrices(joint->Children[j], joint);
}

void CSkinnedMesh::getFrameData(f32 frame, SJoint *joint,
		core::vector3df &position, s32 &positionHint,
		core::vector3df &scale, s32 &scaleHint,
		core::quaternion &rotation, s32 &rotationHint)
{
	s32 foundPositionIndex = -1;
	s32 foundScaleIndex = -1;
	s32 foundRotationIndex = -1;

	if (joint->UseAnimationFrom) {
		const core::array<SPositionKey> &PositionKeys = joint->UseAnimationFrom->PositionKeys;
		const core::array<SScaleKey> &ScaleKeys = joint->UseAnimationFrom->ScaleKeys;
		const core::array<SRotationKey> &RotationKeys = joint->UseAnimationFrom->RotationKeys;

		if (PositionKeys.size()) {
			foundPositionIndex = -1;

			// Test the Hints...
			if (positionHint >= 0 && (u32)positionHint < PositionKeys.size()) {
				// check this hint
				if (positionHint > 0 && PositionKeys[positionHint].frame >= frame && PositionKeys[positionHint - 1].frame < frame)
					foundPositionIndex = positionHint;
				else if (positionHint + 1 < (s32)PositionKeys.size()) {
					// check the next index
					if (PositionKeys[positionHint + 1].frame >= frame &&
							PositionKeys[positionHint + 0].frame < frame) {
						positionHint++;
						foundPositionIndex = positionHint;
					}
				}
			}

			// The hint test failed, do a full scan...
			if (foundPositionIndex == -1) {
				for (u32 i = 0; i < PositionKeys.size(); ++i) {
					if (PositionKeys[i].frame >= frame) { // Keys should to be sorted by frame
						foundPositionIndex = i;
						positionHint = i;
						break;
					}
				}
			}

			// Do interpolation...
			if (foundPositionIndex != -1) {
				if (InterpolationMode == EIM_CONSTANT || foundPositionIndex == 0) {
					position = PositionKeys[foundPositionIndex].position;
				} else if (InterpolationMode == EIM_LINEAR) {
					const SPositionKey &KeyA = PositionKeys[foundPositionIndex];
					const SPositionKey &KeyB = PositionKeys[foundPositionIndex - 1];

					const f32 fd1 = frame - KeyA.frame;
					const f32 fd2 = KeyB.frame - frame;
					position = ((KeyB.position - KeyA.position) / (fd1 + fd2)) * fd1 + KeyA.position;
				}
			}
		}

		//------------------------------------------------------------

		if (ScaleKeys.size()) {
			foundScaleIndex = -1;

			// Test the Hints...
			if (scaleHint >= 0 && (u32)scaleHint < ScaleKeys.size()) {
				// check this hint
				if (scaleHint > 0 && ScaleKeys[scaleHint].frame >= frame && ScaleKeys[scaleHint - 1].frame < frame)
					foundScaleIndex = scaleHint;
				else if (scaleHint + 1 < (s32)ScaleKeys.size()) {
					// check the next index
					if (ScaleKeys[scaleHint + 1].frame >= frame &&
							ScaleKeys[scaleHint + 0].frame < frame) {
						scaleHint++;
						foundScaleIndex = scaleHint;
					}
				}
			}

			// The hint test failed, do a full scan...
			if (foundScaleIndex == -1) {
				for (u32 i = 0; i < ScaleKeys.size(); ++i) {
					if (ScaleKeys[i].frame >= frame) { // Keys should to be sorted by frame
						foundScaleIndex = i;
						scaleHint = i;
						break;
					}
				}
			}

			// Do interpolation...
			if (foundScaleIndex != -1) {
				if (InterpolationMode == EIM_CONSTANT || foundScaleIndex == 0) {
					scale = ScaleKeys[foundScaleIndex].scale;
				} else if (InterpolationMode == EIM_LINEAR) {
					const SScaleKey &KeyA = ScaleKeys[foundScaleIndex];
					const SScaleKey &KeyB = ScaleKeys[foundScaleIndex - 1];

					const f32 fd1 = frame - KeyA.frame;
					const f32 fd2 = KeyB.frame - frame;
					scale = ((KeyB.scale - KeyA.scale) / (fd1 + fd2)) * fd1 + KeyA.scale;
				}
			}
		}

		//-------------------------------------------------------------

		if (RotationKeys.size()) {
			foundRotationIndex = -1;

			// Test the Hints...
			if (rotationHint >= 0 && (u32)rotationHint < RotationKeys.size()) {
				// check this hint
				if (rotationHint > 0 && RotationKeys[rotationHint].frame >= frame && RotationKeys[rotationHint - 1].frame < frame)
					foundRotationIndex = rotationHint;
				else if (rotationHint + 1 < (s32)RotationKeys.size()) {
					// check the next index
					if (RotationKeys[rotationHint + 1].frame >= frame &&
							RotationKeys[rotationHint + 0].frame < frame) {
						rotationHint++;
						foundRotationIndex = rotationHint;
					}
				}
			}

			// The hint test failed, do a full scan...
			if (foundRotationIndex == -1) {
				for (u32 i = 0; i < RotationKeys.size(); ++i) {
					if (RotationKeys[i].frame >= frame) { // Keys should be sorted by frame
						foundRotationIndex = i;
						rotationHint = i;
						break;
					}
				}
			}

			// Do interpolation...
			if (foundRotationIndex != -1) {
				if (InterpolationMode == EIM_CONSTANT || foundRotationIndex == 0) {
					rotation = RotationKeys[foundRotationIndex].rotation;
				} else if (InterpolationMode == EIM_LINEAR) {
					const SRotationKey &KeyA = RotationKeys[foundRotationIndex];
					const SRotationKey &KeyB = RotationKeys[foundRotationIndex - 1];

					const f32 fd1 = frame - KeyA.frame;
					const f32 fd2 = KeyB.frame - frame;
					const f32 t = fd1 / (fd1 + fd2);

					/*
					f32 t = 0;
					if (KeyA.frame!=KeyB.frame)
						t = (frame-KeyA.frame) / (KeyB.frame - KeyA.frame);
					*/

					rotation.slerp(KeyA.rotation, KeyB.rotation, t);
				}
			}
		}
	}
}

//--------------------------------------------------------------------------
//				Software Skinning
//--------------------------------------------------------------------------

//! Preforms a software skin on this mesh based of joint positions
void CSkinnedMesh::skinMesh()
{
	if (!HasAnimation || SkinnedLastFrame)
		return;

	//----------------
	// This is marked as "Temp!".  A shiny dubloon to whomever can tell me why.
	buildAllGlobalAnimatedMatrices();
	//-----------------

	SkinnedLastFrame = true;
	if (!HardwareSkinning) {
		// Software skin....
		u32 i;

		// rigid animation
		for (i = 0; i < AllJoints.size(); ++i) {
			for (u32 j = 0; j < AllJoints[i]->AttachedMeshes.size(); ++j) {
				SSkinMeshBuffer *Buffer = (*SkinningBuffers)[AllJoints[i]->AttachedMeshes[j]];
				Buffer->Transformation = AllJoints[i]->GlobalAnimatedMatrix;
			}
		}

		// clear skinning helper array
		for (i = 0; i < Vertices_Moved.size(); ++i)
			for (u32 j = 0; j < Vertices_Moved[i].size(); ++j)
				Vertices_Moved[i][j] = false;

		// skin starting with the root joints
		for (i = 0; i < RootJoints.size(); ++i)
			skinJoint(RootJoints[i], 0);

		for (i = 0; i < SkinningBuffers->size(); ++i)
			(*SkinningBuffers)[i]->setDirty(EBT_VERTEX);
	}
	updateBoundingBox();
}

void CSkinnedMesh::skinJoint(SJoint *joint, SJoint *parentJoint)
{
	if (joint->Weights.size()) {
		// Find this joints pull on vertices...
		core::matrix4 jointVertexPull(core::matrix4::EM4CONST_NOTHING);
		jointVertexPull.setbyproduct(joint->GlobalAnimatedMatrix, joint->GlobalInversedMatrix);

		core::vector3df thisVertexMove, thisNormalMove;

		core::array<scene::SSkinMeshBuffer *> &buffersUsed = *SkinningBuffers;

		// Skin Vertices Positions and Normals...
		for (u32 i = 0; i < joint->Weights.size(); ++i) {
			SWeight &weight = joint->Weights[i];

			// Pull this vertex...
			jointVertexPull.transformVect(thisVertexMove, weight.StaticPos);

			if (AnimateNormals)
				jointVertexPull.rotateVect(thisNormalMove, weight.StaticNormal);

			if (!(*(weight.Moved))) {
				*(weight.Moved) = true;

				buffersUsed[weight.buffer_id]->getVertex(weight.vertex_id)->Pos = thisVertexMove * weight.strength;

				if (AnimateNormals)
					buffersUsed[weight.buffer_id]->getVertex(weight.vertex_id)->Normal = thisNormalMove * weight.strength;

				//*(weight._Pos) = thisVertexMove * weight.strength;
			} else {
				buffersUsed[weight.buffer_id]->getVertex(weight.vertex_id)->Pos += thisVertexMove * weight.strength;

				if (AnimateNormals)
					buffersUsed[weight.buffer_id]->getVertex(weight.vertex_id)->Normal += thisNormalMove * weight.strength;

				//*(weight._Pos) += thisVertexMove * weight.strength;
			}

			buffersUsed[weight.buffer_id]->boundingBoxNeedsRecalculated();
		}
	}

	// Skin all children
	for (u32 j = 0; j < joint->Children.size(); ++j)
		skinJoint(joint->Children[j], joint);
}

E_ANIMATED_MESH_TYPE CSkinnedMesh::getMeshType() const
{
	return EAMT_SKINNED;
}

//! Gets joint count.
u32 CSkinnedMesh::getJointCount() const
{
	return AllJoints.size();
}

//! Gets the name of a joint.
const std::optional<std::string> &CSkinnedMesh::getJointName(u32 number) const
{
	if (number >= getJointCount()) {
		static const std::optional<std::string> nullopt;
		return nullopt;
	}
	return AllJoints[number]->Name;
}

//! Gets a joint number from its name
std::optional<u32> CSkinnedMesh::getJointNumber(const std::string &name) const
{
	for (u32 i = 0; i < AllJoints.size(); ++i) {
		if (AllJoints[i]->Name == name)
			return i;
	}

	return std::nullopt;
}

//! returns amount of mesh buffers.
u32 CSkinnedMesh::getMeshBufferCount() const
{
	return LocalBuffers.size();
}

//! returns pointer to a mesh buffer
IMeshBuffer *CSkinnedMesh::getMeshBuffer(u32 nr) const
{
	if (nr < LocalBuffers.size())
		return LocalBuffers[nr];
	else
		return 0;
}

//! Returns pointer to a mesh buffer which fits a material
IMeshBuffer *CSkinnedMesh::getMeshBuffer(const video::SMaterial &material) const
{
	for (u32 i = 0; i < LocalBuffers.size(); ++i) {
		if (LocalBuffers[i]->getMaterial() == material)
			return LocalBuffers[i];
	}
	return 0;
}

//! returns an axis aligned bounding box
const core::aabbox3d<f32> &CSkinnedMesh::getBoundingBox() const
{
	return BoundingBox;
}

//! set user axis aligned bounding box
void CSkinnedMesh::setBoundingBox(const core::aabbox3df &box)
{
	BoundingBox = box;
}

//! set the hardware mapping hint, for driver
void CSkinnedMesh::setHardwareMappingHint(E_HARDWARE_MAPPING newMappingHint,
		E_BUFFER_TYPE buffer)
{
	for (u32 i = 0; i < LocalBuffers.size(); ++i)
		LocalBuffers[i]->setHardwareMappingHint(newMappingHint, buffer);
}

//! flags the meshbuffer as changed, reloads hardware buffers
void CSkinnedMesh::setDirty(E_BUFFER_TYPE buffer)
{
	for (u32 i = 0; i < LocalBuffers.size(); ++i)
		LocalBuffers[i]->setDirty(buffer);
}

//! uses animation from another mesh
bool CSkinnedMesh::useAnimationFrom(const ISkinnedMesh *mesh)
{
	bool unmatched = false;

	for (u32 i = 0; i < AllJoints.size(); ++i) {
		SJoint *joint = AllJoints[i];
		joint->UseAnimationFrom = 0;

		if (joint->Name == "")
			unmatched = true;
		else {
			for (u32 j = 0; j < mesh->getAllJoints().size(); ++j) {
				SJoint *otherJoint = mesh->getAllJoints()[j];
				if (joint->Name == otherJoint->Name) {
					joint->UseAnimationFrom = otherJoint;
				}
			}
			if (!joint->UseAnimationFrom)
				unmatched = true;
		}
	}

	checkForAnimation();

	return !unmatched;
}

//! Update Normals when Animating
//! False= Don't animate them, faster
//! True= Update normals (default)
void CSkinnedMesh::updateNormalsWhenAnimating(bool on)
{
	AnimateNormals = on;
}

//! Sets Interpolation Mode
void CSkinnedMesh::setInterpolationMode(E_INTERPOLATION_MODE mode)
{
	InterpolationMode = mode;
}

core::array<scene::SSkinMeshBuffer *> &CSkinnedMesh::getMeshBuffers()
{
	return LocalBuffers;
}

core::array<CSkinnedMesh::SJoint *> &CSkinnedMesh::getAllJoints()
{
	return AllJoints;
}

const core::array<CSkinnedMesh::SJoint *> &CSkinnedMesh::getAllJoints() const
{
	return AllJoints;
}

//! (This feature is not implemented in irrlicht yet)
bool CSkinnedMesh::setHardwareSkinning(bool on)
{
	if (HardwareSkinning != on) {
		if (on) {

			// set mesh to static pose...
			for (u32 i = 0; i < AllJoints.size(); ++i) {
				SJoint *joint = AllJoints[i];
				for (u32 j = 0; j < joint->Weights.size(); ++j) {
					const u16 buffer_id = joint->Weights[j].buffer_id;
					const u32 vertex_id = joint->Weights[j].vertex_id;
					LocalBuffers[buffer_id]->getVertex(vertex_id)->Pos = joint->Weights[j].StaticPos;
					LocalBuffers[buffer_id]->getVertex(vertex_id)->Normal = joint->Weights[j].StaticNormal;
					LocalBuffers[buffer_id]->boundingBoxNeedsRecalculated();
				}
			}
		}

		HardwareSkinning = on;
	}
	return HardwareSkinning;
}

void CSkinnedMesh::refreshJointCache()
{
	// copy cache from the mesh...
	for (u32 i = 0; i < AllJoints.size(); ++i) {
		SJoint *joint = AllJoints[i];
		for (u32 j = 0; j < joint->Weights.size(); ++j) {
			const u16 buffer_id = joint->Weights[j].buffer_id;
			const u32 vertex_id = joint->Weights[j].vertex_id;
			joint->Weights[j].StaticPos = LocalBuffers[buffer_id]->getVertex(vertex_id)->Pos;
			joint->Weights[j].StaticNormal = LocalBuffers[buffer_id]->getVertex(vertex_id)->Normal;
		}
	}
}

void CSkinnedMesh::resetAnimation()
{
	// copy from the cache to the mesh...
	for (u32 i = 0; i < AllJoints.size(); ++i) {
		SJoint *joint = AllJoints[i];
		for (u32 j = 0; j < joint->Weights.size(); ++j) {
			const u16 buffer_id = joint->Weights[j].buffer_id;
			const u32 vertex_id = joint->Weights[j].vertex_id;
			LocalBuffers[buffer_id]->getVertex(vertex_id)->Pos = joint->Weights[j].StaticPos;
			LocalBuffers[buffer_id]->getVertex(vertex_id)->Normal = joint->Weights[j].StaticNormal;
		}
	}
	SkinnedLastFrame = false;
	LastAnimatedFrame = -1;
}

void CSkinnedMesh::calculateGlobalMatrices(SJoint *joint, SJoint *parentJoint)
{
	if (!joint && parentJoint) // bit of protection from endless loops
		return;

	// Go through the root bones
	if (!joint) {
		for (u32 i = 0; i < RootJoints.size(); ++i)
			calculateGlobalMatrices(RootJoints[i], 0);
		return;
	}

	if (!parentJoint)
		joint->GlobalMatrix = joint->LocalMatrix;
	else
		joint->GlobalMatrix = parentJoint->GlobalMatrix * joint->LocalMatrix;

	joint->LocalAnimatedMatrix = joint->LocalMatrix;
	joint->GlobalAnimatedMatrix = joint->GlobalMatrix;

	if (joint->GlobalInversedMatrix.isIdentity()) { // might be pre calculated
		joint->GlobalInversedMatrix = joint->GlobalMatrix;
		joint->GlobalInversedMatrix.makeInverse(); // slow
	}

	for (u32 j = 0; j < joint->Children.size(); ++j)
		calculateGlobalMatrices(joint->Children[j], joint);
	SkinnedLastFrame = false;
}

void CSkinnedMesh::checkForAnimation()
{
	u32 i, j;
	// Check for animation...
	HasAnimation = false;
	for (i = 0; i < AllJoints.size(); ++i) {
		if (AllJoints[i]->UseAnimationFrom) {
			if (AllJoints[i]->UseAnimationFrom->PositionKeys.size() ||
					AllJoints[i]->UseAnimationFrom->ScaleKeys.size() ||
					AllJoints[i]->UseAnimationFrom->RotationKeys.size()) {
				HasAnimation = true;
			}
		}
	}

	// meshes with weights, are still counted as animated for ragdolls, etc
	if (!HasAnimation) {
		for (i = 0; i < AllJoints.size(); ++i) {
			if (AllJoints[i]->Weights.size())
				HasAnimation = true;
		}
	}

	if (HasAnimation) {
		//--- Find the length of the animation ---
		EndFrame = 0;
		for (i = 0; i < AllJoints.size(); ++i) {
			if (AllJoints[i]->UseAnimationFrom) {
				if (AllJoints[i]->UseAnimationFrom->PositionKeys.size())
					if (AllJoints[i]->UseAnimationFrom->PositionKeys.getLast().frame > EndFrame)
						EndFrame = AllJoints[i]->UseAnimationFrom->PositionKeys.getLast().frame;

				if (AllJoints[i]->UseAnimationFrom->ScaleKeys.size())
					if (AllJoints[i]->UseAnimationFrom->ScaleKeys.getLast().frame > EndFrame)
						EndFrame = AllJoints[i]->UseAnimationFrom->ScaleKeys.getLast().frame;

				if (AllJoints[i]->UseAnimationFrom->RotationKeys.size())
					if (AllJoints[i]->UseAnimationFrom->RotationKeys.getLast().frame > EndFrame)
						EndFrame = AllJoints[i]->UseAnimationFrom->RotationKeys.getLast().frame;
			}
		}
	}

	if (HasAnimation && !PreparedForSkinning) {
		PreparedForSkinning = true;

		// check for bugs:
		for (i = 0; i < AllJoints.size(); ++i) {
			SJoint *joint = AllJoints[i];
			for (j = 0; j < joint->Weights.size(); ++j) {
				const u16 buffer_id = joint->Weights[j].buffer_id;
				const u32 vertex_id = joint->Weights[j].vertex_id;

				// check for invalid ids
				if (buffer_id >= LocalBuffers.size()) {
					os::Printer::log("Skinned Mesh: Weight buffer id too large", ELL_WARNING);
					joint->Weights[j].buffer_id = joint->Weights[j].vertex_id = 0;
				} else if (vertex_id >= LocalBuffers[buffer_id]->getVertexCount()) {
					os::Printer::log("Skinned Mesh: Weight vertex id too large", ELL_WARNING);
					joint->Weights[j].buffer_id = joint->Weights[j].vertex_id = 0;
				}
			}
		}

		// An array used in skinning

		for (i = 0; i < Vertices_Moved.size(); ++i)
			for (j = 0; j < Vertices_Moved[i].size(); ++j)
				Vertices_Moved[i][j] = false;

		// For skinning: cache weight values for speed

		for (i = 0; i < AllJoints.size(); ++i) {
			SJoint *joint = AllJoints[i];
			for (j = 0; j < joint->Weights.size(); ++j) {
				const u16 buffer_id = joint->Weights[j].buffer_id;
				const u32 vertex_id = joint->Weights[j].vertex_id;

				joint->Weights[j].Moved = &Vertices_Moved[buffer_id][vertex_id];
				joint->Weights[j].StaticPos = LocalBuffers[buffer_id]->getVertex(vertex_id)->Pos;
				joint->Weights[j].StaticNormal = LocalBuffers[buffer_id]->getVertex(vertex_id)->Normal;

				// joint->Weights[j]._Pos=&Buffers[buffer_id]->getVertex(vertex_id)->Pos;
			}
		}

		// normalize weights
		normalizeWeights();
	}
	SkinnedLastFrame = false;
}

//! called by loader after populating with mesh and bone data
void CSkinnedMesh::finalize()
{
	os::Printer::log("Skinned Mesh - finalize", ELL_DEBUG);
	u32 i;

	// Make sure we recalc the next frame
	LastAnimatedFrame = -1;
	SkinnedLastFrame = false;

	// calculate bounding box
	for (i = 0; i < LocalBuffers.size(); ++i) {
		LocalBuffers[i]->recalculateBoundingBox();
	}

	if (AllJoints.size() || RootJoints.size()) {
		// populate AllJoints or RootJoints, depending on which is empty
		if (!RootJoints.size()) {

			for (u32 CheckingIdx = 0; CheckingIdx < AllJoints.size(); ++CheckingIdx) {

				bool foundParent = false;
				for (i = 0; i < AllJoints.size(); ++i) {
					for (u32 n = 0; n < AllJoints[i]->Children.size(); ++n) {
						if (AllJoints[i]->Children[n] == AllJoints[CheckingIdx])
							foundParent = true;
					}
				}

				if (!foundParent)
					RootJoints.push_back(AllJoints[CheckingIdx]);
			}
		} else {
			AllJoints = RootJoints;
		}
	}

	for (i = 0; i < AllJoints.size(); ++i) {
		AllJoints[i]->UseAnimationFrom = AllJoints[i];
	}

	// Set array sizes...

	for (i = 0; i < LocalBuffers.size(); ++i) {
		Vertices_Moved.push_back(core::array<char>());
		Vertices_Moved[i].set_used(LocalBuffers[i]->getVertexCount());
	}

	checkForAnimation();

	if (HasAnimation) {
		irr::u32 redundantPosKeys = 0;
		irr::u32 unorderedPosKeys = 0;
		irr::u32 redundantScaleKeys = 0;
		irr::u32 unorderedScaleKeys = 0;
		irr::u32 redundantRotationKeys = 0;
		irr::u32 unorderedRotationKeys = 0;

		//--- optimize and check keyframes ---
		for (i = 0; i < AllJoints.size(); ++i) {
			core::array<SPositionKey> &PositionKeys = AllJoints[i]->PositionKeys;
			core::array<SScaleKey> &ScaleKeys = AllJoints[i]->ScaleKeys;
			core::array<SRotationKey> &RotationKeys = AllJoints[i]->RotationKeys;

			// redundant = identical middle keys - we only need the first and last frame
			// unordered = frames which are out of order - we can't handle those
			redundantPosKeys += dropMiddleKeys<SPositionKey>(PositionKeys, identicalPos);
			unorderedPosKeys += dropBadKeys<SPositionKey>(PositionKeys);
			redundantScaleKeys += dropMiddleKeys<SScaleKey>(ScaleKeys, identicalScale);
			unorderedScaleKeys += dropBadKeys<SScaleKey>(ScaleKeys);
			redundantRotationKeys += dropMiddleKeys<SRotationKey>(RotationKeys, identicalRotation);
			unorderedRotationKeys += dropBadKeys<SRotationKey>(RotationKeys);

			// Fill empty keyframe areas
			if (PositionKeys.size()) {
				SPositionKey *Key;
				Key = &PositionKeys[0]; // getFirst
				if (Key->frame != 0) {
					PositionKeys.push_front(*Key);
					Key = &PositionKeys[0]; // getFirst
					Key->frame = 0;
				}

				Key = &PositionKeys.getLast();
				if (Key->frame != EndFrame) {
					PositionKeys.push_back(*Key);
					Key = &PositionKeys.getLast();
					Key->frame = EndFrame;
				}
			}

			if (ScaleKeys.size()) {
				SScaleKey *Key;
				Key = &ScaleKeys[0]; // getFirst
				if (Key->frame != 0) {
					ScaleKeys.push_front(*Key);
					Key = &ScaleKeys[0]; // getFirst
					Key->frame = 0;
				}

				Key = &ScaleKeys.getLast();
				if (Key->frame != EndFrame) {
					ScaleKeys.push_back(*Key);
					Key = &ScaleKeys.getLast();
					Key->frame = EndFrame;
				}
			}

			if (RotationKeys.size()) {
				SRotationKey *Key;
				Key = &RotationKeys[0]; // getFirst
				if (Key->frame != 0) {
					RotationKeys.push_front(*Key);
					Key = &RotationKeys[0]; // getFirst
					Key->frame = 0;
				}

				Key = &RotationKeys.getLast();
				if (Key->frame != EndFrame) {
					RotationKeys.push_back(*Key);
					Key = &RotationKeys.getLast();
					Key->frame = EndFrame;
				}
			}
		}

		if (redundantPosKeys > 0) {
			os::Printer::log("Skinned Mesh - redundant position frames kicked", core::stringc(redundantPosKeys).c_str(), ELL_DEBUG);
		}
		if (unorderedPosKeys > 0) {
			irr::os::Printer::log("Skinned Mesh - unsorted position frames kicked", irr::core::stringc(unorderedPosKeys).c_str(), irr::ELL_DEBUG);
		}
		if (redundantScaleKeys > 0) {
			os::Printer::log("Skinned Mesh - redundant scale frames kicked", core::stringc(redundantScaleKeys).c_str(), ELL_DEBUG);
		}
		if (unorderedScaleKeys > 0) {
			irr::os::Printer::log("Skinned Mesh - unsorted scale frames kicked", irr::core::stringc(unorderedScaleKeys).c_str(), irr::ELL_DEBUG);
		}
		if (redundantRotationKeys > 0) {
			os::Printer::log("Skinned Mesh - redundant rotation frames kicked", core::stringc(redundantRotationKeys).c_str(), ELL_DEBUG);
		}
		if (unorderedRotationKeys > 0) {
			irr::os::Printer::log("Skinned Mesh - unsorted rotation frames kicked", irr::core::stringc(unorderedRotationKeys).c_str(), irr::ELL_DEBUG);
		}
	}

	// Needed for animation and skinning...

	calculateGlobalMatrices(0, 0);

	// animateMesh(0, 1);
	// buildAllLocalAnimatedMatrices();
	// buildAllGlobalAnimatedMatrices();

	// rigid animation for non animated meshes
	for (i = 0; i < AllJoints.size(); ++i) {
		for (u32 j = 0; j < AllJoints[i]->AttachedMeshes.size(); ++j) {
			SSkinMeshBuffer *Buffer = (*SkinningBuffers)[AllJoints[i]->AttachedMeshes[j]];
			Buffer->Transformation = AllJoints[i]->GlobalAnimatedMatrix;
		}
	}

	// calculate bounding box
	if (LocalBuffers.empty())
		BoundingBox.reset(0, 0, 0);
	else {
		irr::core::aabbox3df bb(LocalBuffers[0]->BoundingBox);
		LocalBuffers[0]->Transformation.transformBoxEx(bb);
		BoundingBox.reset(bb);

		for (u32 j = 1; j < LocalBuffers.size(); ++j) {
			bb = LocalBuffers[j]->BoundingBox;
			LocalBuffers[j]->Transformation.transformBoxEx(bb);

			BoundingBox.addInternalBox(bb);
		}
	}
}

void CSkinnedMesh::updateBoundingBox(void)
{
	if (!SkinningBuffers)
		return;

	core::array<SSkinMeshBuffer *> &buffer = *SkinningBuffers;
	BoundingBox.reset(0, 0, 0);

	if (!buffer.empty()) {
		for (u32 j = 0; j < buffer.size(); ++j) {
			buffer[j]->recalculateBoundingBox();
			core::aabbox3df bb = buffer[j]->BoundingBox;
			buffer[j]->Transformation.transformBoxEx(bb);

			BoundingBox.addInternalBox(bb);
		}
	}
}

scene::SSkinMeshBuffer *CSkinnedMesh::addMeshBuffer()
{
	scene::SSkinMeshBuffer *buffer = new scene::SSkinMeshBuffer();
	LocalBuffers.push_back(buffer);
	return buffer;
}

CSkinnedMesh::SJoint *CSkinnedMesh::addJoint(SJoint *parent)
{
	SJoint *joint = new SJoint;

	AllJoints.push_back(joint);
	if (!parent) {
		// Add root joints to array in finalize()
	} else {
		// Set parent (Be careful of the mesh loader also setting the parent)
		parent->Children.push_back(joint);
	}

	return joint;
}

CSkinnedMesh::SPositionKey *CSkinnedMesh::addPositionKey(SJoint *joint)
{
	if (!joint)
		return 0;

	joint->PositionKeys.push_back(SPositionKey());
	return &joint->PositionKeys.getLast();
}

CSkinnedMesh::SScaleKey *CSkinnedMesh::addScaleKey(SJoint *joint)
{
	if (!joint)
		return 0;

	joint->ScaleKeys.push_back(SScaleKey());
	return &joint->ScaleKeys.getLast();
}

CSkinnedMesh::SRotationKey *CSkinnedMesh::addRotationKey(SJoint *joint)
{
	if (!joint)
		return 0;

	joint->RotationKeys.push_back(SRotationKey());
	return &joint->RotationKeys.getLast();
}

CSkinnedMesh::SWeight *CSkinnedMesh::addWeight(SJoint *joint)
{
	if (!joint)
		return 0;

	joint->Weights.push_back(SWeight());
	return &joint->Weights.getLast();
}

bool CSkinnedMesh::isStatic()
{
	return !HasAnimation;
}

void CSkinnedMesh::normalizeWeights()
{
	// note: unsure if weights ids are going to be used.

	// Normalise the weights on bones....

	u32 i, j;
	core::array<core::array<f32>> verticesTotalWeight;

	verticesTotalWeight.reallocate(LocalBuffers.size());
	for (i = 0; i < LocalBuffers.size(); ++i) {
		verticesTotalWeight.push_back(core::array<f32>());
		verticesTotalWeight[i].set_used(LocalBuffers[i]->getVertexCount());
	}

	for (i = 0; i < verticesTotalWeight.size(); ++i)
		for (j = 0; j < verticesTotalWeight[i].size(); ++j)
			verticesTotalWeight[i][j] = 0;

	for (i = 0; i < AllJoints.size(); ++i) {
		SJoint *joint = AllJoints[i];
		for (j = 0; j < joint->Weights.size(); ++j) {
			if (joint->Weights[j].strength <= 0) { // Check for invalid weights
				joint->Weights.erase(j);
				--j;
			} else {
				verticesTotalWeight[joint->Weights[j].buffer_id][joint->Weights[j].vertex_id] += joint->Weights[j].strength;
			}
		}
	}

	for (i = 0; i < AllJoints.size(); ++i) {
		SJoint *joint = AllJoints[i];
		for (j = 0; j < joint->Weights.size(); ++j) {
			const f32 total = verticesTotalWeight[joint->Weights[j].buffer_id][joint->Weights[j].vertex_id];
			if (total != 0 && total != 1)
				joint->Weights[j].strength /= total;
		}
	}
}

void CSkinnedMesh::recoverJointsFromMesh(core::array<IBoneSceneNode *> &jointChildSceneNodes)
{
	for (u32 i = 0; i < AllJoints.size(); ++i) {
		IBoneSceneNode *node = jointChildSceneNodes[i];
		SJoint *joint = AllJoints[i];
		node->setPosition(joint->LocalAnimatedMatrix.getTranslation());
		node->setRotation(joint->LocalAnimatedMatrix.getRotationDegrees());
		node->setScale(joint->LocalAnimatedMatrix.getScale());

		node->positionHint = joint->positionHint;
		node->scaleHint = joint->scaleHint;
		node->rotationHint = joint->rotationHint;

		node->updateAbsolutePosition();
	}
}

void CSkinnedMesh::transferJointsToMesh(const core::array<IBoneSceneNode *> &jointChildSceneNodes)
{
	for (u32 i = 0; i < AllJoints.size(); ++i) {
		const IBoneSceneNode *const node = jointChildSceneNodes[i];
		SJoint *joint = AllJoints[i];

		joint->LocalAnimatedMatrix.setRotationDegrees(node->getRotation());
		joint->LocalAnimatedMatrix.setTranslation(node->getPosition());
		joint->LocalAnimatedMatrix *= core::matrix4().setScale(node->getScale());

		joint->positionHint = node->positionHint;
		joint->scaleHint = node->scaleHint;
		joint->rotationHint = node->rotationHint;

		joint->GlobalSkinningSpace = (node->getSkinningSpace() == EBSS_GLOBAL);
	}
	// Make sure we recalc the next frame
	LastAnimatedFrame = -1;
	SkinnedLastFrame = false;
}

void CSkinnedMesh::transferOnlyJointsHintsToMesh(const core::array<IBoneSceneNode *> &jointChildSceneNodes)
{
	for (u32 i = 0; i < AllJoints.size(); ++i) {
		const IBoneSceneNode *const node = jointChildSceneNodes[i];
		SJoint *joint = AllJoints[i];

		joint->positionHint = node->positionHint;
		joint->scaleHint = node->scaleHint;
		joint->rotationHint = node->rotationHint;
	}
	SkinnedLastFrame = false;
}

void CSkinnedMesh::addJoints(core::array<IBoneSceneNode *> &jointChildSceneNodes,
		IAnimatedMeshSceneNode *node, ISceneManager *smgr)
{
	// Create new joints
	for (u32 i = 0; i < AllJoints.size(); ++i) {
		jointChildSceneNodes.push_back(new CBoneSceneNode(0, smgr, 0, i, AllJoints[i]->Name));
	}

	// Match up parents
	for (u32 i = 0; i < jointChildSceneNodes.size(); ++i) {
		const SJoint *const joint = AllJoints[i]; // should be fine

		s32 parentID = -1;

		for (u32 j = 0; (parentID == -1) && (j < AllJoints.size()); ++j) {
			if (i != j) {
				const SJoint *const parentTest = AllJoints[j];
				for (u32 n = 0; n < parentTest->Children.size(); ++n) {
					if (parentTest->Children[n] == joint) {
						parentID = j;
						break;
					}
				}
			}
		}

		IBoneSceneNode *bone = jointChildSceneNodes[i];
		if (parentID != -1)
			bone->setParent(jointChildSceneNodes[parentID]);
		else
			bone->setParent(node);

		bone->drop();
	}
	SkinnedLastFrame = false;
}

void CSkinnedMesh::convertMeshToTangents()
{
	// now calculate tangents
	for (u32 b = 0; b < LocalBuffers.size(); ++b) {
		if (LocalBuffers[b]) {
			LocalBuffers[b]->convertToTangents();

			const s32 idxCnt = LocalBuffers[b]->getIndexCount();

			u16 *idx = LocalBuffers[b]->getIndices();
			video::S3DVertexTangents *v =
					(video::S3DVertexTangents *)LocalBuffers[b]->getVertices();

			for (s32 i = 0; i < idxCnt; i += 3) {
				calculateTangents(
						v[idx[i + 0]].Normal,
						v[idx[i + 0]].Tangent,
						v[idx[i + 0]].Binormal,
						v[idx[i + 0]].Pos,
						v[idx[i + 1]].Pos,
						v[idx[i + 2]].Pos,
						v[idx[i + 0]].TCoords,
						v[idx[i + 1]].TCoords,
						v[idx[i + 2]].TCoords);

				calculateTangents(
						v[idx[i + 1]].Normal,
						v[idx[i + 1]].Tangent,
						v[idx[i + 1]].Binormal,
						v[idx[i + 1]].Pos,
						v[idx[i + 2]].Pos,
						v[idx[i + 0]].Pos,
						v[idx[i + 1]].TCoords,
						v[idx[i + 2]].TCoords,
						v[idx[i + 0]].TCoords);

				calculateTangents(
						v[idx[i + 2]].Normal,
						v[idx[i + 2]].Tangent,
						v[idx[i + 2]].Binormal,
						v[idx[i + 2]].Pos,
						v[idx[i + 0]].Pos,
						v[idx[i + 1]].Pos,
						v[idx[i + 2]].TCoords,
						v[idx[i + 0]].TCoords,
						v[idx[i + 1]].TCoords);
			}
		}
	}
}

void CSkinnedMesh::calculateTangents(
		core::vector3df &normal,
		core::vector3df &tangent,
		core::vector3df &binormal,
		const core::vector3df &vt1, const core::vector3df &vt2, const core::vector3df &vt3, // vertices
		const core::vector2df &tc1, const core::vector2df &tc2, const core::vector2df &tc3) // texture coords
{
	core::vector3df v1 = vt1 - vt2;
	core::vector3df v2 = vt3 - vt1;
	normal = v2.crossProduct(v1);
	normal.normalize();

	// binormal

	f32 deltaX1 = tc1.X - tc2.X;
	f32 deltaX2 = tc3.X - tc1.X;
	binormal = (v1 * deltaX2) - (v2 * deltaX1);
	binormal.normalize();

	// tangent

	f32 deltaY1 = tc1.Y - tc2.Y;
	f32 deltaY2 = tc3.Y - tc1.Y;
	tangent = (v1 * deltaY2) - (v2 * deltaY1);
	tangent.normalize();

	// adjust

	core::vector3df txb = tangent.crossProduct(binormal);
	if (txb.dotProduct(normal) < 0.0f) {
		tangent *= -1.0f;
		binormal *= -1.0f;
	}
}

} // end namespace scene
} // end namespace irr
