Transform.cpp

#include "Defines.h"
#include "Transform.h"

void Transform::LookTo(const XMFLOAT3& direction, const XMFLOAT3& up)
{
	XMMATRIX View = XMMatrixLookToLH(XMLoadFloat3(&m_Position), XMLoadFloat3(&direction), XMLoadFloat3(&up));
	XMMATRIX InvView = XMMatrixInverse(nullptr, View);
	XMFLOAT4X4 rotMatrix;
	XMStoreFloat4x4(&rotMatrix, InvView);
	m_Rotation = GetEulerAnglesFromRotationMatrix(rotMatrix);
}

XMFLOAT3 Transform::GetEulerAnglesFromRotationMatrix(const XMFLOAT4X4& rotationMatrix)
{
	float c = sqrtf(1.0f - rotationMatrix(2, 1) * rotationMatrix(2, 1));
	// 防止r[2][1]出现大于1的情况
	if (isnan(c))
		c = 0.0f;
	XMFLOAT3 rotation;
	rotation.z = atan2f(rotationMatrix(0, 1), rotationMatrix(1, 1));
	rotation.x = atan2f(-rotationMatrix(2, 1), c);
	rotation.y = atan2f(rotationMatrix(2, 0), rotationMatrix(2, 2));
	return rotation;
}

void Transform::SetPosition(const XMFLOAT3& position)
{
	m_Position = position;
}

XMMATRIX Transform::GetLocalToWorldMatrixXM() const
{
	XMVECTOR scaleVec = XMLoadFloat3(&m_Scale);
	XMVECTOR rotationVec = XMLoadFloat3(&m_Rotation);
	XMVECTOR positionVec = XMLoadFloat3(&m_Position);
	XMMATRIX World = XMMatrixScalingFromVector(scaleVec) * XMMatrixRotationRollPitchYawFromVector(rotationVec) * XMMatrixTranslationFromVector(positionVec);
	return World;
}

XMMATRIX Transform::GetWorldToLocalMatrixXM() const
{
	XMMATRIX invWorld = XMMatrixInverse(nullptr, GetLocalToWorldMatrixXM());
	return invWorld;
}