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      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
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Krankles

Trying to Convert Simple Java ECS to C++

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Hi, I'm reading up on ECS on t-machine and other places, but now I'm trying to implement my own simple ECS. I'm stuck on trying to convert https://github.com/adamgit/Entity-System-RDBMS-Inspired-Java from Java to C++. In the EntityManager, he has a variable called componentStores which is defined as 

HashMap<Class, HashMap<Integer, ? extends Component>> componentStores;

However, I don't know the equivalent of this in C++.

 

So far, I've been able to create and generate entity ids, but I don't know how to actually add the component to the entity in a map. In the hashmap above, what types of data is it containing? Also, the second hashmap inside the hashmap, is the "? extends Component" supposed to be a pointer to a given Component? For example, I made a PositionComponent, would the hashmap contain a pointer to the PositionComponent? And, what is the point of the first data type "Class?" Sorry if this doesn't make sense, I don't fully understand what's happening, but the big question is how can you convert the hashmap into C++?

 

My entity header file looks like this:

#ifndef ENTITY_MANAGER_H
#define ENTITY_MANAGER_H

#include <map>
#include <vector>
#include <cstdint>
#include <iostream>
#include <algorithm>

class EntityManager
{
public:
        EntityManager();
        ~EntityManager();

        uint32_t create_entity();
        void kill_entity(uint32_t id);

private:
        std::vector<uint32_t> entity_list;
        uint32_t assignable_entity_id;

        uint32_t generate_entity_id();
};

#endif

and this is my EntityManager source file

#include "EntityManager.h"

EntityManager::EntityManager()
: assignable_entity_id(1)
{

};

EntityManager::~EntityManager()
{

};

uint32_t EntityManager::create_entity()
{
        uint32_t id = generate_entity_id();

        if (id < 1) {
                // throw error
                return 0;
        } else {
                entity_list.push_back(id);
                return id;
        }
}

uint32_t EntityManager::generate_entity_id()
{
        if (assignable_entity_id < UINT32_MAX) {
                std::cout << "Generated ID: " << assignable_entity_id << std::endl;
                return assignable_entity_id++;
        } else {
                for (unsigned int i = 1; i < UINT32_MAX; i++) {
                        std::vector<uint32_t>::iterator it = std::find(entity_list.begin(), entity_list.end(), i);
                        if (*it != i) {
                                std::cout << "Generated ID: " << i << std::endl;
                                return i;
                        }
                }

                // throw error
                return 0;
        }
}

void EntityManager::kill_entity(uint32_t id)
{
        std::vector<uint32_t>::iterator it = entity_list.begin();
        for (; it != entity_list.end(); it++) {
                if (*it == id) {
                        std::cout << "Killing Entity: " << *it << std::endl;
                        entity_list.erase(it);
                        return;
                }
        }
} 

Any help would be greatly appreciated, thanks.

Edited by Krankles
0

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