AtCam.cpp

#include "AtCam.h"

AtCam::AtCam(XMFLOAT3 position, XMFLOAT3 at, XMFLOAT3 up, FLOAT windowWidth, FLOAT windowHeight, FLOAT nearDepth, FLOAT farDepth) {
	_eye = position;
	_at = at;
	_up = up;

	_windowWidth = windowWidth;
	_windowHeight = windowHeight;
	_nearDepth = nearDepth;
	_farDepth = farDepth;

	//initialize the view matrix default
	UpdateView();

	//initialize the projection matrix
	Reshape(_windowWidth, _windowHeight, _nearDepth, _farDepth);

	//default
	_distance = 5.0f;
	_currentAngle = 0.0f;
}

void AtCam::UpdateView()
{
	XMVECTOR posVec = XMVectorSet(_eye.x, _eye.y, _eye.z, 0.0f);
	XMVECTOR atVec = XMVectorSet(_at.x, _at.y, _at.z, 0.0f);
	XMVECTOR upVec = XMVectorSet(_up.x, _up.y, _up.z, 0.0f);

	XMStoreFloat4x4(&_view, XMMatrixLookAtLH(posVec, atVec, upVec));
}

void AtCam::Update(Input* nextInput, float deltaT)
{
	const float movementSpeed = 5.0f;
	const float rotateSpeed = 3.0f;

	//zoom
	if (nextInput->KeyWDown()) {
		_distance -= deltaT * movementSpeed;
	}
	if (nextInput->KeySDown()) {
		_distance += deltaT * movementSpeed;
	}

	//rotate
	if (nextInput->KeyADown()) {
		_currentAngle -= deltaT * rotateSpeed;
	}
	if (nextInput->KeyDDown()) {
		_currentAngle += deltaT * rotateSpeed;
	}

	//boundaries
	if (_distance < 1.0f) _distance = 1.0f;

	//calculate next positions based on circle algorithm.
	//research reference link: https://funprogramming.org/68-Circular-motion-reviewed.html
	_eye.x = _at.x + cosf(_currentAngle) * _distance; //uses angle to tell location of orbit
	_eye.z = _at.z + sinf(_currentAngle) * _distance;

	UpdateView();
}