Nuake-custom/Nuake/src/Resource/SkeletalAnimation.h

#pragma once
#include "src/Core/Core.h"
#include <src/Rendering/Mesh/Bone.h>

#include "src/Resource/Serializable.h"
#include "src/Resource/Resource.h"

namespace Nuake
{
	struct SkeletonAnimationBoneAnimation
	{
		std::string Name;
		Vector3 Positions;
		Quat Rotations;
		Vector3 Scalings;
	};

	class BoneTransformTrack
	{
	private:
		std::vector<float> m_PositionTimestamps = {};
		std::vector<float> m_RotationTimestamps = {};
		std::vector<float> m_ScaleTimestamps = {};

		std::vector<Vector3> m_Positions = {};
		std::vector<Quat> m_Rotations = {};
		std::vector<Vector3> m_Scales = {};

		Matrix4 m_PositionTransform;
		Matrix4 m_RotationTransform;
		Matrix4 m_ScaleTransform;
		Matrix4 m_FinalTransform;

		bool m_IsEmpty = true;
	public:
		BoneTransformTrack();
		~BoneTransformTrack() = default;

		bool IsEmpty() const { return m_IsEmpty; }

		void PushPositionKeyframe(float timestamp, const Vector3& position)
		{
			m_IsEmpty = false;
			m_PositionTimestamps.push_back(timestamp);
			m_Positions.push_back(position);
		}

		void PushRotationKeyframe(float timestamp, const Quat& rotation)
		{
			m_IsEmpty = false;
			m_RotationTimestamps.push_back(timestamp);
			m_Rotations.push_back(rotation);
		}

		void PushScaleKeyframe(float timestamp, const Vector3& scale)
		{
			m_IsEmpty = false;
			m_ScaleTimestamps.push_back(timestamp);
			m_Scales.push_back(scale);
		}

		void Update(float time)
		{
			// We cannot use const reference here because we would compare the reference to previous pos 
			// to the m_PositionTransform and previous pos always equale.
			// Making the hasChanged always false. We would end up comparing the same values always.
			const Matrix4 previousPos = m_PositionTransform;
			const Matrix4 previousRot = m_RotationTransform;
			const Matrix4 previousSca = m_ScaleTransform;
			m_PositionTransform = InterpolatePosition(time);
			m_RotationTransform = InterpolateRotation(time);
			m_ScaleTransform = InterpolateScale(time);

			bool hasChanged = previousPos != m_PositionTransform || previousRot != m_RotationTransform || previousSca != m_ScaleTransform;
			if (hasChanged)
			{
				m_FinalTransform = m_PositionTransform * m_RotationTransform * m_ScaleTransform;
			}
		}

		const Matrix4& GetFinalTransform() const
		{
			return m_FinalTransform;
		}

		int GetPositionIndex(float animationTime)
		{
			if (m_Positions.empty())
			{
				return 0;
			}

			for (int index = 0; index < m_Positions.size() - 1; index++)
			{
				if (animationTime < m_PositionTimestamps[index + 1])
				{
					return index;
				}
			}

			return static_cast<int>(m_Positions.size()) - 1;
		}

		/* Gets the current index on mKeyRotations to interpolate to based on the
		current animation time*/
		int GetRotationIndex(float animationTime)
		{
			for (int index = 0; index < m_Rotations.size() - 1; ++index)
			{
				if (animationTime < m_RotationTimestamps[index + 1])
				{
					return index;
				}
			}

			return static_cast<int>(m_Rotations.size()) - 1;
		}

		/* Gets the current index on mKeyScalings to interpolate to based on the
		current animation time */
		int GetScaleIndex(float animationTime)
		{
			for (int index = 0; index < m_Scales.size() - 1; ++index)
			{
				if (animationTime < m_ScaleTimestamps[index + 1])
				{
					return index;
				}
			}

			return static_cast<int>(m_Scales.size()) - 1;
		}

		float GetScaleFactor(float lastTime, float nextTime, float animationTime);
		Matrix4 InterpolatePosition(float time);
		Matrix4 InterpolateRotation(float time);
		Matrix4 InterpolateScale(float time);

		json Serialize();
		bool Deserialize(const json& j);
	};

	class SkeletalAnimation : public Resource, ISerializable
	{
	private:
		std::unordered_map<std::string, BoneTransformTrack> m_Tracks;
		float m_CurrentTime;
		float m_Duration;
		float m_TicksPerSecond;
		std::string m_Name;
		bool m_Loop = false;

	public:
		SkeletalAnimation() = default;
		SkeletalAnimation(const std::string& name, float duration, float ticksPerSecond);

		~SkeletalAnimation() = default;

		void SetCurrentTime(float time) 
		{
			if (m_Loop)
			{
				m_CurrentTime = fmod(time, m_Duration);
			}
			else
			{
				m_CurrentTime = std::max(time, m_Duration);
			}
		}

		float GetCurrentTime() const { return m_CurrentTime; }
		void SetDuration(float duration) { m_Duration = duration; }
		float GetDuration() const { return m_Duration; }
		float GetTicksPerSecond() const { return m_TicksPerSecond; }
		void SetTicksPerSecond(float ticks) { m_TicksPerSecond = ticks; }

		const std::string& GetName() const { return m_Name; }
		BoneTransformTrack& GetTrack(const std::string& name);
		std::unordered_map<std::string, BoneTransformTrack>& GetTracks() { return m_Tracks; }

		json Serialize() override;
		bool Deserialize(const json& j) override;
	};
}