2018-soft-3d-renderer/Source/Transform.cpp

#include "Matrix.hpp"
#include "Transform.hpp"
#include <cmath>


Matrix Transform_Translate(Point& translation)
{
	Matrix result;

	result.e41 = translation.x;
	result.e42 = translation.y;
	result.e43 = translation.z;

	return result;
}

Matrix Transform_Rotate(Point& rotation)
{
	// YXZ Euler rotation
	float cosThetaY = cosf(rotation.y);
	float sinThetaY = sinf(rotation.y);

	Matrix tRotateY;

	tRotateY.e11 = cosThetaY;
	tRotateY.e13 = -sinThetaY;
	tRotateY.e31 = sinThetaY;
	tRotateY.e33 = cosThetaY;


	float cosThetaX = cosf(rotation.x);
	float sinThetaX = sinf(rotation.x);

	Matrix tRotateX;

	tRotateX.e22 = cosThetaX;
	tRotateX.e23 = sinThetaX;
	tRotateX.e32 = -sinThetaX;
	tRotateX.e33 = cosThetaX;


	float cosThetaZ = cosf(rotation.z);
	float sinThetaZ = sinf(rotation.z);

	Matrix tRotateZ;

	tRotateZ.e11 = cosThetaZ;
	tRotateZ.e12 = sinThetaZ;
	tRotateZ.e21 = -sinThetaZ;
	tRotateZ.e22 = cosThetaZ;


	Matrix result = tRotateY * tRotateX * tRotateZ;

	return result;
}

Matrix Transform_Scale(float scale)
{
	Matrix result;

	result.e11 = scale;
	result.e22 = scale;
	result.e33 = scale;

	return result;
}

Matrix Transform_View(Camera& camera)
{
	Point invPosition = -camera.position;
	Matrix tInvTranslate = Transform_Translate(invPosition);

	Point invRotation = -camera.rotation;
	Matrix tInvRotate = Transform_Rotate(invRotation);

	Matrix result = tInvTranslate * tInvRotate;

	return result;
}

Matrix Transform_Perspective(Camera& camera)
{
	Matrix result;

	result.e11 = camera.xZoom;
	result.e22 = camera.yZoom;
	result.e33 = camera.zClipBias0;
	result.e34 = 1;
	result.e43 = camera.zClipBias1;

	return result;
}

Matrix Transform_Screen(Camera& camera)
{
	Matrix result;

	result.e11 = camera.xScale;
	result.e41 = camera.xScale;
	result.e22 = -camera.yScale;
	result.e42 = camera.yScale;

	return result;
}