meemknight.PikaEngine/Pika/gameplay/containers/milk/physics.h

#pragma once
#include <glm/glm.hpp>
#include <vector>
#include <unordered_map>

constexpr int TYPE_CIRCLE = 0;
constexpr int TYPE_BOX = 1;
constexpr int TYPE_CILINDRU = 2;

constexpr static float MAX_VELOCITY = 10'000;
constexpr static float MAX_ACCELERATION = 10'000;
constexpr static float MAX_AIR_DRAG = 100;


struct PhysicsObject
{
	//the position represents the center of the object.
	// the shape is the width height depth for cube and for circle it is radius.

	glm::vec3 position = {};    // 12 bytes

	glm::vec3 shape = {};

	glm::vec3 velocity = {};

	glm::vec3 acceleration = {};

	glm::vec3 collisionDir = {};


	float mass = 1;
	float bouncyness = 0.9;
	int type = 0;
	float staticFriction = 0.4;

	float dynamicFriction = 0.3;

	bool collidesBottom = 0;
	bool collidesSide = 0;
	glm::vec3 collisionVector = {};

	glm::vec3 getMin()
	{
		if (type == TYPE_CIRCLE)
		{
			glm::vec3 rez = position;
			rez -= glm::vec3(shape.x, shape.x, shape.x);
			return rez;
		}
		else if (type == TYPE_BOX)
		{
			glm::vec3 rez = position;
			rez -= glm::vec3(shape) / 2.f;
			return rez;
		}
		else if (type == TYPE_CILINDRU)
		{
			glm::vec3 rez = position;
			rez -= glm::vec3(shape.x, shape.y / 2.f, shape.x);
			return rez;
		}
	}

	glm::vec3 getMax()
	{
		if (type == TYPE_CIRCLE)
		{
			glm::vec3 rez = position;
			rez += glm::vec3(shape.x, shape.x, shape.x);
			return rez;
		}
		else if (type == TYPE_BOX)
		{
			glm::vec3 rez = position;
			rez += glm::vec3(shape) / 2.f;
			return rez;
		}if (type == TYPE_CILINDRU)
		{
			glm::vec3 rez = position;
			rez += glm::vec3(shape.x, shape.y / 2.f, shape.x);
			return rez;
		}
	}

};


PhysicsObject createBall(glm::vec3 pos, float r);

PhysicsObject createBox(glm::vec3 pos, glm::vec3 size);

PhysicsObject createCilindru(glm::vec3 pos, float r, float h);


struct Simulator
{
	std::unordered_map<int, PhysicsObject> bodies;

	void updateForces(PhysicsObject &object, float deltaTime);

	int id = 1;

	int getIdAndIncrement()
	{
		return id++;
	}

	glm::vec3 boxDimensions = {200, 100, 200};

	void update(float deltaTime);

};