#ifndef Cylinder_H
#define Cylinder_H

#include <vector>
#include "glm/glm/glm.hpp"
#define _USE_MATH_DEFINES
#include <math.h>
#include "Shape.h"

class Cylinder: public Shape {
public:
	//creates a clinder of with radius r and length l centered at the origin. Res specifies the amount of segments used for the bottom and top circle
	Cylinder(float r, float length, int res) : Shape() {
		//filling the vertex buffer
		vertexBuffer.reserve(2 * res);
		//lower ring
		for (int i = 0; i < res; i++) {
			Vertex cur;
			cur.position = glm::vec3( r * sin(i * 2 * M_PI / res),-length / 2,r * cos(i * 2 * M_PI / res) );
			cur.normal = cur.position;
			cur.normal.y = 0;
			cur.normal = glm::normalize(cur.normal);
			vertexBuffer.push_back(cur);
		}
		//upper ring
		for (int i = 0; i < res; i++) {
			Vertex cur;
			cur.position = { r * sin(i * 2 * M_PI / res),length / 2,r * cos(i * 2 * M_PI / res) };
			cur.normal = cur.position;
			cur.normal.y = 0;
			cur.normal = glm::normalize(cur.normal);
			vertexBuffer.push_back(cur);
		}

		//filling the indexbuffer
		for (int i = 0; i < res; i++) {
			indexBuffer.push_back(i);
			indexBuffer.push_back(i +res);
			indexBuffer.push_back((i + 1) % res + res);

			indexBuffer.push_back((i + 1) % res + res);
			indexBuffer.push_back((i + 1) % res);
			indexBuffer.push_back(i);
		}
	};

	~Cylinder() {};

	std::vector<Vertex> getVertexBuffer() {
		return std::vector<Vertex>(vertexBuffer);
	};

	std::vector<uint32_t> getIndexBuffer(uint32_t startOffset) {
		std::vector<uint32_t> iB(indexBuffer);

		if (startOffset == 0)
			return iB;

		for (uint32_t& i : iB) {
			i += startOffset;
		}

		return iB;
	};

private:
	std::vector<Vertex> vertexBuffer;
	std::vector<uint32_t> indexBuffer;
};

#endif