Camera2D.cpp

#include "Camera2D.h"

namespace NeroEngine{
	Camera2D::Camera2D() :_position(0.0f, 0.0f), 
		_cameraMatrix(1.0f), 
		_orthoMatrix(1.0f), 
		_scale(1.0f), 
		_needsMatrixUpdate(true),
		_screenWidth(100),
		_screenHeight(100)
	{
		
	}


	Camera2D::~Camera2D()
	{
	}
	void Camera2D::init(int screenWidth, int screenHeight){
		_screenWidth = screenWidth;
		_screenHeight = screenHeight; 
		_orthoMatrix = glm::ortho(0.0f, float(_screenWidth), 0.0f, float(_screenHeight));
	}
	void Camera2D::update(){
		if (_needsMatrixUpdate){
		

			glm::vec3 translate(-_position.x + _screenWidth / 2.0f, -_position.y + _screenHeight / 2.0f, 0.0f);
			_cameraMatrix = glm::translate(_orthoMatrix, translate);

			glm::vec3 scale(_scale,_scale,0.0f);
			_cameraMatrix = glm::scale(glm::mat4(1.0f), scale) * _cameraMatrix;

	

			_needsMatrixUpdate = false;
		}
	}
	glm::vec2 Camera2D::convertScreenToWorld(glm::vec2 screenCoords){
		//invert dir Y
		screenCoords.y = _screenHeight - screenCoords.y;
		//in the center
		screenCoords -= glm::vec2(_screenWidth / 2, _screenHeight / 2);
		//scala the coordnates
		screenCoords /= _scale;
		//translate with the camera position
		screenCoords += _position;

		return screenCoords;
	}
	bool Camera2D::isBoxiInView(const glm::vec2& position, const glm::vec2& dimensions){
		
		glm::vec2 scaledScreenDimensions = glm::vec2(_screenWidth, _screenHeight) / (_scale);

		float MIN_DISTANCE_X = dimensions.x / 2.0f + scaledScreenDimensions.x/2.0f;
		float MIN_DISTANCE_Y = dimensions.y / 2.0f + scaledScreenDimensions.y/2.0f;
		
		glm::vec2 centerPos = position + dimensions/2.0f;
		glm::vec2 centerCameraPos = _position;
		glm::vec2 distVec = centerPos - centerCameraPos;

		float xDepth = MIN_DISTANCE_X - abs(distVec.x);
		float yDepth = MIN_DISTANCE_Y - abs(distVec.y);

		if (xDepth>0 && yDepth>0){
			//Åöײ
			return true;
		}
		return false;
	
	}
}