From 18cda59205c1f940e82f2431769b3fea8bed22ca Mon Sep 17 00:00:00 2001
From: Lightling <contactlightling@gmail.com>
Date: Sat, 5 Feb 2022 22:15:43 -0500
Subject: [PATCH] create transform class

---
 Transform.cpp | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++
 Transform.h   | 35 +++++++++++++++++++
 2 files changed, 131 insertions(+)
 create mode 100644 Transform.cpp
 create mode 100644 Transform.h

diff --git a/Transform.cpp b/Transform.cpp
new file mode 100644
index 0000000..c4fc1d0
--- /dev/null
+++ b/Transform.cpp
@@ -0,0 +1,96 @@
+#include "Transform.h"
+
+using namespace DirectX;
+
+Transform::Transform()
+{
+	SetPosition(0, 0, 0);
+	SetRotation(0, 0, 0);
+	SetScale(1, 1, 1);
+
+	XMStoreFloat4x4(&worldMatrix, XMMatrixIdentity());
+	XMStoreFloat4x4(&worldMatrixInverseTranspose, XMMatrixIdentity());
+	worldMatrixChanged = false;
+}
+
+DirectX::XMFLOAT3 Transform::GetPosition()		{ return position; }
+DirectX::XMFLOAT3 Transform::GetEulerAngles()	{ return eulerAngles; }
+DirectX::XMFLOAT3 Transform::GetPitchYawRoll()	{ return eulerAngles;  }
+DirectX::XMFLOAT3 Transform::GetScale()			{ return scale; }
+
+DirectX::XMFLOAT4X4 Transform::GetWorldMatrix()
+{
+	if (worldMatrixChanged)
+	{
+		UpdateWorldMatrix();
+		worldMatrixChanged = false;
+	}
+	return worldMatrix;
+}
+
+DirectX::XMFLOAT4X4 Transform::GetWorldMatrixInverseTranspose()
+{
+	if (worldMatrixChanged)
+	{
+		UpdateWorldMatrix();
+		worldMatrixChanged = false;
+	}
+	return worldMatrixInverseTranspose;
+}
+
+// XMVECTOR & XMStoreFloat compiles down to something faster than position += x,y,z because it happens all at once
+
+void Transform::SetPosition(float _x, float _y, float _z)
+{
+	XMVECTOR newPosition = XMVectorSet(_x, _y, _z, 0);
+	XMStoreFloat3(&position, newPosition);
+	worldMatrixChanged = true;
+}
+
+void Transform::SetRotation(float _pitch, float _yaw, float _roll)
+{
+	XMVECTOR newRotation = XMVectorSet(_pitch, _yaw, _roll, 0);
+	XMStoreFloat3(&eulerAngles, newRotation);
+	worldMatrixChanged = true;
+}
+
+void Transform::SetScale(float _x, float _y, float _z)
+{
+	XMVECTOR newScale = XMVectorSet(_x, _y, _z, 0);
+	XMStoreFloat3(&scale, newScale);
+	worldMatrixChanged = true;
+}
+
+void Transform::TranslateAbsolute(float _x, float _y, float _z)
+{
+	XMVECTOR newPosition = XMLoadFloat3(&position);
+	XMVECTOR offset = XMVectorSet(_x, _y, _z, 0);
+	XMStoreFloat3(&position, newPosition + offset);
+	worldMatrixChanged = true;
+}
+
+void Transform::Rotate(float _pitch, float _yaw, float _roll)
+{
+	XMVECTOR newRotation = XMLoadFloat3(&position);
+	XMVECTOR offset = XMVectorSet(_pitch, _yaw, _roll, 0);
+	XMStoreFloat3(&eulerAngles, newRotation + offset);
+	worldMatrixChanged = true;
+}
+
+void Transform::Scale(float _x, float _y, float _z)
+{
+	XMVECTOR newScale = XMLoadFloat3(&position);
+	XMVECTOR offset = XMVectorSet(_x, _y, _z, 0);
+	XMStoreFloat3(&scale, newScale + offset);
+	worldMatrixChanged = true;
+}
+
+void Transform::UpdateWorldMatrix()
+{
+	XMMATRIX matrixPosition = XMMatrixTranslation(position.x, position.y, position.z);
+	XMMATRIX matrixRotation = XMMatrixRotationRollPitchYaw(eulerAngles.x, eulerAngles.y, eulerAngles.z);
+	XMMATRIX matrixScale = XMMatrixScaling(scale.x, scale.y, scale.z);
+
+	XMStoreFloat4x4(&worldMatrix, matrixScale * matrixRotation * matrixPosition);
+	XMStoreFloat4x4(&worldMatrixInverseTranspose, XMMatrixInverse(0, XMMatrixTranspose(XMLoadFloat4x4(&worldMatrix))));
+}
diff --git a/Transform.h b/Transform.h
new file mode 100644
index 0000000..359b24d
--- /dev/null
+++ b/Transform.h
@@ -0,0 +1,35 @@
+#pragma once
+
+#include <DirectXMath.h>
+
+class Transform
+{
+public:
+	Transform();
+
+	DirectX::XMFLOAT3		GetPosition();
+	DirectX::XMFLOAT3		GetEulerAngles();
+	DirectX::XMFLOAT3		GetPitchYawRoll(); // an alternative name for euler angles in case preferred
+	DirectX::XMFLOAT3		GetScale();
+	DirectX::XMFLOAT4X4		GetWorldMatrix();
+	DirectX::XMFLOAT4X4		GetWorldMatrixInverseTranspose();
+
+	void					SetPosition(float _x, float _y, float _z);
+	void					SetRotation(float _pitch, float _yaw, float _roll);
+	void					SetScale(float _x, float _y, float _z);
+
+	void					TranslateAbsolute(float _x, float _y, float _z);
+	void					Rotate(float _pitch, float _yaw, float _roll);
+	void					Scale(float _x, float _y, float _z);
+
+
+private:
+	DirectX::XMFLOAT3		position;
+	DirectX::XMFLOAT3		eulerAngles;
+	DirectX::XMFLOAT3		scale;
+	DirectX::XMFLOAT4X4		worldMatrix;
+	DirectX::XMFLOAT4X4		worldMatrixInverseTranspose;
+	bool					worldMatrixChanged;
+
+	void					UpdateWorldMatrix();
+};