Fix animation blending

irr/include/SkinnedMesh.h

@@ -231,7 +231,7 @@ public:
 
 		static core::quaternion interpolateValue(core::quaternion from, core::quaternion to, f32 time) {
 			core::quaternion result;
-			result.slerp(from, to, time, 0.001f);
+			result.slerp(from, to, time);
 			return result;
 		}
 

irr/include/Transform.h

@@ -2,7 +2,6 @@
 
 #include "irrMath.h"
 #include <matrix4.h>
-#include <variant>
 #include <vector3d.h>
 #include <quaternion.h>
 
@@ -27,12 +26,23 @@ struct Transform {
 		};
 	}
 
+
+	Transform interpolate(Transform to, f32 time) const
+	{
+		core::quaternion interpolated_rotation;
+		interpolated_rotation.slerp(rotation, to.rotation, time);
+		return {
+			to.translation.getInterpolated(translation, time),
+			interpolated_rotation,
+			to.scale.getInterpolated(scale, time),
+		};
+	}
+
 	matrix4 buildMatrix() const
 	{
 		matrix4 T;
 		T.setTranslation(translation);
 		matrix4 R;
-		// TODO this is sussy. probably shouldn't be doing this.
 		rotation.getMatrix_transposed(R);
 		matrix4 S;
 		S.setScale(scale);

irr/include/quaternion.h

@@ -180,7 +180,7 @@ public:
 	linear interpolation.
 	*/
 	quaternion &slerp(quaternion q1, quaternion q2,
-			f32 time, f32 threshold = .05f);
+			f32 time, f32 threshold = .001f);
 
 	//! Set this quaternion to represent a rotation from angle and axis.
 	/** Axis must be unit length.

irr/src/CAnimatedMeshSceneNode.cpp

@@ -540,6 +540,8 @@ void CAnimatedMeshSceneNode::addJoints()
 	const auto &joints = static_cast<SkinnedMesh*>(Mesh)->getAllJoints();
 	JointChildSceneNodes.clear();
 	JointChildSceneNodes.reserve(joints.size());
+	PretransitingSave.clear();
+	PretransitingSave.resize(JointChildSceneNodes.size());
 	for (size_t i = 0; i < joints.size(); ++i) {
 		const auto *joint = joints[i];
 		ISceneNode *parent = this;
@@ -587,43 +589,11 @@ void CAnimatedMeshSceneNode::animateJoints()
 	//-----------------------------------------
 
 	if (Transiting != 0.f) {
-		// Init additional matrices
-		if (PretransitingSave.size() < JointChildSceneNodes.size()) {
-			for (u32 n = PretransitingSave.size(); n < JointChildSceneNodes.size(); ++n)
-				PretransitingSave.push_back(core::matrix4());
+		for (u32 i = 0; i < JointChildSceneNodes.size(); ++i) {
+			if (PretransitingSave[i]) {
+				JointChildSceneNodes[i]->setTransform(PretransitingSave[i]->interpolate(
+						JointChildSceneNodes[i]->getTransform(), TransitingBlend));
 			}
-
-		for (u32 n = 0; n < JointChildSceneNodes.size(); ++n) {
-			//------Position------
-
-			JointChildSceneNodes[n]->setPosition(
-					core::lerp(
-							PretransitingSave[n].getTranslation(),
-							JointChildSceneNodes[n]->getPosition(),
-							TransitingBlend));
-
-			//------Rotation------
-
-			// Code is slow, needs to be fixed up
-
-			const core::quaternion RotationStart(PretransitingSave[n].getRotationDegrees() * core::DEGTORAD);
-			const core::quaternion RotationEnd(JointChildSceneNodes[n]->getRotation() * core::DEGTORAD);
-
-			core::quaternion QRotation;
-			QRotation.slerp(RotationStart, RotationEnd, TransitingBlend);
-
-			core::vector3df tmpVector;
-			QRotation.toEuler(tmpVector);
-			tmpVector *= core::RADTODEG; // convert from radians back to degrees
-			JointChildSceneNodes[n]->setRotation(tmpVector);
-
-			//------Scale------
-
-			// JointChildSceneNodes[n]->setScale(
-			//		core::lerp(
-			//			PretransitingSave[n].getScale(),
-			//			JointChildSceneNodes[n]->getScale(),
-			//			TransitingBlend));
 		}
 	}
 }
@@ -648,15 +618,14 @@ void CAnimatedMeshSceneNode::beginTransition()
 		return;
 
 	if (TransitionTime != 0) {
-		// Check the array is big enough
-		if (PretransitingSave.size() < JointChildSceneNodes.size()) {
-			for (u32 n = PretransitingSave.size(); n < JointChildSceneNodes.size(); ++n)
-				PretransitingSave.push_back(core::matrix4());
+		// Copy the transforms of animated joints
+		for (u32 i = 0; i < JointChildSceneNodes.size(); ++i) {
+			if (!JointChildSceneNodes[i]->Matrix) {
+				PretransitingSave[i] = JointChildSceneNodes[i]->getTransform();
+			} else {
+				PretransitingSave[i] = std::nullopt;
+			}
 		}
-
-		// Copy the position of joints
-		for (u32 n = 0; n < JointChildSceneNodes.size(); ++n)
-			PretransitingSave[n] = JointChildSceneNodes[n]->getRelativeTransformation();
 
 		Transiting = core::reciprocal((f32)TransitionTime);
 	}

irr/src/CAnimatedMeshSceneNode.h

@@ -4,11 +4,12 @@
 
 #pragma once
 
+#include "CBoneSceneNode.h"
 #include "IAnimatedMeshSceneNode.h"
 #include "IAnimatedMesh.h"
 
 #include "SkinnedMesh.h"
-#include "matrix4.h"
+#include "Transform.h"
 
 namespace irr
 {
@@ -171,8 +172,8 @@ private:
 	s32 PassCount;
 	std::function<void(f32)> OnAnimateCallback;
 
-	std::vector<IBoneSceneNode *> JointChildSceneNodes;
-	core::array<core::matrix4> PretransitingSave;
+	std::vector<CBoneSceneNode *> JointChildSceneNodes;
+	std::vector<std::optional<core::Transform>> PretransitingSave;
 };
 
 } // end namespace scene

irr/src/CBoneSceneNode.h

@@ -46,6 +46,15 @@ public:
 		setScale(transform.scale);
 	}
 
+	core::Transform getTransform() const
+	{
+		return {
+			getPosition(),
+			core::quaternion(getRotation() * core::DEGTORAD).makeInverse(),
+			getScale()
+		};
+	}
+
 	core::matrix4 getRelativeTransformation() const override
 	{
 		if (Matrix)