CirclesRefsPointers/Circles/Circles.cpp

#define OLC_PGE_APPLICATION
#include "olcPixelGameEngine.h"

// Override base class with your custom functionality
class CircleExample : public olc::PixelGameEngine
{
	struct Circle{
		Circle(olc::vf2d pos,float radius)
			:pos(pos),radius(radius){
			std::cout<<"Circle created!"<<std::endl;
		}
		Circle(const Circle&circle)
			:pos(circle.pos),radius(circle.radius){
			std::cout<<"Circle copied!"<<std::endl;
		}
		olc::vf2d pos;
		float radius;
	};
	struct CircleGroup{
		std::vector<Circle*>circles;
	};
public:
	CircleExample()
	{
		// Name your application
		sAppName = "Circles Example";
	}

	std::vector<Circle>circleList;
	std::vector<CircleGroup>circleGroupList;

public:
	bool OnUserCreate() override
	{
		// Called once at the start, so create things here
		for(int y=0;y<5;y++){
			for(int x=0;x<5;x++){
				Circle myCircle = {olc::vf2d{x*16.f,y*16.f},8};
				circleList.push_back(myCircle);
			}
		}

		CircleGroup myGroup;
		myGroup.circles.push_back(&circleList[3]);
		myGroup.circles.push_back(&circleList[4]);
		myGroup.circles.push_back(&circleList[9]);
		circleGroupList.push_back(myGroup);

		for(CircleGroup&circleGroup : circleGroupList){
			for(Circle*c : circleGroup.circles){
				c->pos+={20,0};
			}
		}
		return true;
	}

	bool OnUserUpdate(float fElapsedTime) override
	{
		// Called once per frame, draws random coloured pixels
		Clear(olc::VERY_DARK_GREEN);

		olc::vf2d drawOffset = {64,64};

		for(Circle&c : circleList){
			DrawCircle(c.pos+drawOffset,c.radius);
		}
		for(CircleGroup&circleGroup : circleGroupList){
			for(Circle*c : circleGroup.circles){
				DrawCircle(c->pos+drawOffset,c->radius,olc::RED);
			}
		}
		return true;
	}
};

int main()
{
	CircleExample demo;
	if (demo.Construct(256, 240, 4, 4))
		demo.Start();
	return 0;
}