triangles/Particle.hpp

/**
 *  Triangles
 *  Copyright (C) 2016 POSITIVE MENTAL ATTITUDE
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, version 3 of the License.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 /**
  * This is based on a wiki entry
  * https://github.com/SFML/SFML/wiki/Source:-Particle-System
  */

#pragma once

#include <vector>
#include <SFML/Graphics.hpp>
#include <iostream>

class ParticleSystem: public sf::Drawable
{
	public:
		ParticleSystem(int width, int height);
		~ParticleSystem();

		void fuel(int particles, float angle);
		void update(sf::Time delta);
		void render();
		void clear();
		
		void enable(bool enabled)
		{
			_enabled = enabled;
		}
		const bool isEnabled() const
		{
			return _enabled;
		}
		void loadColors(const sf::Image& image)
		{
			_colors.clear();
			for(unsigned i = 0; i < image.getSize().x; ++i)
				for(unsigned j = 0; j < image.getSize().y; ++j)
				{
					sf::Color color = image.getPixel(i, j);
					if(color.r > 0 || color.g > 0 || color.b > 0)
						_colors.emplace_back(color.r, color.g, color.b, 255);
				}
		}
		void setPosition(const sf::Vector2f position) 
		{ 
			_sprite.setPosition(position - _origin);
		}
		void setPosition(float x, float y) 
		{ 
			setPosition(sf::Vector2f(x, y));
		}
		void setOrigin(const sf::Vector2f origin) 
		{ 
			_origin = origin;
		}
		void setOrigin(float x, float y) 
		{ 
			setOrigin(sf::Vector2f(x, y));
		}
		void setParticleSpeed(float particleSpeed) 
		{ 
			_particleSpeed = particleSpeed; 
		}
		void setDissolutionRate(float dissolutionRate) 
		{ 
			_dissolutionRate = dissolutionRate; 
		}
		const sf::Sprite& getSprite() const
		{ 
			return _sprite; 
		}
 
	private:
		struct Particle
		{
			sf::Vector2f pos;
			sf::Vector2f vel;
			sf::Color color;
			float transparency;
		};
		virtual void draw(sf::RenderTarget& target, sf::RenderStates states) const;
		sf::Vector2f			_origin;
		sf::Clock				_clock;
		sf::Image				_image;
		sf::Texture				_texture;
		sf::Sprite				_sprite;
		float					_particleSpeed;
		float	 				_dissolutionRate;
		std::vector<Particle*>	_particles;
		std::vector<sf::Color>	_colors;
		bool _enabled;
};