├── .gitattributes
├── .gitignore
├── .travis.yml
├── CMakeLists.txt
├── LICENSE
├── README.md
├── examples
└── example.cpp
├── img
├── component_memory_pool.png
└── componentmask_version_vector.png
├── include
├── BaseEntity.h
├── BaseEntity.inl
├── ComponentManager.h
├── ComponentManager.inl
├── Defines.h
├── Entity.h
├── Entity.inl
├── EntityAlias.h
├── EntityAlias.inl
├── EntityManager.h
├── EntityManager.inl
├── Id.h
├── Id.inl
├── Iterator.h
├── Iterator.inl
├── Pool.h
├── Pool.inl
├── Property.h
├── Property.inl
├── System.h
├── System.inl
├── SystemManager.h
├── SystemManager.inl
├── UnallocatedEntity.h
├── UnallocatedEntity.inl
├── Utils.h
├── View.h
├── View.inl
└── ecs.h
├── scripts
├── generate_header.py
└── travis.sh
├── single_include
└── ecs.h
└── test
├── common
├── main.cpp
└── thirdparty
│ └── catch.hpp
├── ecs.cpp
└── ecs_performance.cpp
/.gitattributes:
--------------------------------------------------------------------------------
1 | img/componentmask_version_vector.png filter=lfs diff=lfs merge=lfs -text
2 | img/component_memory_pool.png filter=lfs diff=lfs merge=lfs -text
3 |
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/.gitignore:
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1 | # System files
2 | .DS_Store
3 |
4 | # IDE files
5 | .idea/*
6 | .ycm_extra_conf.py
7 | .ycm_extra_conf.pyc
8 |
9 |
10 | # Compiled Object files
11 | *.slo
12 | *.lo
13 | *.o
14 | *.obj
15 | build*/
16 |
17 | # Precompiled Headers
18 | *.gch
19 | *.pch
20 |
21 | # Compiled Dynamic libraries
22 | *.so
23 | *.dylib
24 | *.dll
25 |
26 | # Fortran module files
27 | *.mod
28 |
29 | # Compiled Static libraries
30 | *.lai
31 | *.la
32 | *.a
33 | *.lib
34 |
35 | # Executables
36 | *.exe
37 | *.out
38 | *.app
39 |
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/.travis.yml:
--------------------------------------------------------------------------------
1 | language: cpp
2 |
3 | compiler:
4 | - clang
5 | - gcc
6 |
7 | sudo: false
8 |
9 | install:
10 | - if [ "$CXX" = "g++" ]; then export CXX="g++-4.8" CC="gcc-4.8"; fi
11 |
12 | addons:
13 | apt:
14 | sources:
15 | - ubuntu-toolchain-r-test
16 | packages:
17 | - cmake
18 | - gcc-4.8
19 | - g++-4.8
20 | - clang
21 |
22 |
23 | script: ./scripts/travis.sh
--------------------------------------------------------------------------------
/CMakeLists.txt:
--------------------------------------------------------------------------------
1 | cmake_minimum_required(VERSION 2.8)
2 |
3 | set( PROJ_NAME "OpenEcs" )
4 | set( PROJ_PATH ${CMAKE_SOURCE_DIR} )
5 | set( PROJ_OUT_PATH ${CMAKE_BINARY_DIR} )
6 | set( PROJ_SOURCES "")
7 | set( PROJ_HEADERS "")
8 | set( PROJ_TEST_SOURCES "")
9 | set( PROJ_TEST_HEADERS "")
10 |
11 | set( CMAKE_MODULE_PATH "${PROJ_PATH}/cmake")
12 | set( EXECUTABLE_OUTPUT_PATH ${PROJ_OUT_PATH})
13 |
14 | set( PROJ_LIB_PATH "${PROJ_PATH}/lib" )
15 | set( PROJ_INCLUDES "${PROJ_PATH}/include")
16 | set( PROJ_TEST_INCLUDES "${PROJ_PATH}/test")
17 | set( LIB_INCLUDES "${PROJ_LIB_PATH}/include")
18 |
19 | project(${PROJ_NAME})
20 | include(ExternalProject)
21 |
22 | # Default compiler args
23 | if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "(GNU|.*Clang)")
24 | set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pedantic -Werror -Wall -Wextra -Wno-unused-parameter -Wno-error=unused-variable -Wno-error=sign-compare -std=c++11")
25 | set(CMAKE_CXX_FLAGS_DEBUG "-O0 -g")
26 | set(CMAKE_CXX_FLAGS_MINSIZEREL "-g -Os -DNDEBUG")
27 | set(CMAKE_CXX_FLAGS_RELEASE "-g -O2 -DNDEBUG")
28 | set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O2 -g")
29 | elseif("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
30 | # /Zi - Produces a program database (PDB) that contains type information and symbolic debugging information for use with the debugger.
31 | # /FS - Allows multiple cl.exe processes to write to the same .pdb file
32 | # /DEBUG - Enable debug during linking
33 | # /Od - Disables optimization
34 | set(CMAKE_CXX_FLAGS_DEBUG "/Zi /FS /DEBUG /Od /MDd")
35 | # /Ox - Full optimization
36 | set(CMAKE_CXX_FLAGS_RELEASE "/Ox -DNDEBUG")
37 | set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "/Ox /Zi /FS /DEBUG")
38 | endif()
39 |
40 | if (NOT CMAKE_BUILD_TYPE)
41 | message("-- Defaulting to release build (use -DCMAKE_BUILD_TYPE:STRING=Debug for debug build)")
42 | set(CMAKE_BUILD_TYPE "Release")
43 | endif()
44 |
45 | # Adds sources and headers to project
46 | file( GLOB_RECURSE PROJ_SOURCES include/*.cpp)
47 | file( GLOB_RECURSE PROJ_HEADERS include/*.h include/*.inl)
48 | file( GLOB_RECURSE PROJ_TEST_SOURCES test/common/*.cpp )
49 | file( GLOB_RECURSE PROJ_TEST_HEADERS test/common/*.hpp )
50 | include_directories( ${PROJ_INCLUDES} ${LIB_INCLUDES} ${PROJ_TEST_INCLUDES})
51 |
52 | # Tests
53 | enable_testing()
54 | add_executable( UnitTests ${PROJ_TEST_SOURCES} test/ecs.cpp ${PROJ_TEST_HEADERS} ${PROJ_HEADERS})
55 | add_executable( PerformanceTests ${PROJ_TEST_SOURCES} test/ecs_performance.cpp ${PROJ_TEST_HEADERS} ${PROJ_HEADERS})
56 | add_executable( Example examples/example.cpp ${PROJ_HEADERS})
57 |
58 | add_test( UnitTests UnitTests)
59 | add_test( PerformanceTests PerformanceTests)
60 |
61 | install(TARGETS UnitTests DESTINATION ${PROJ_OUT_PATH})
62 | install(TARGETS PerformanceTests DESTINATION ${PROJ_OUT_PATH})
63 | install(TARGETS Example DESTINATION ${PROJ_OUT_PATH})
64 |
65 |
--------------------------------------------------------------------------------
/LICENSE:
--------------------------------------------------------------------------------
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623 | How to Apply These Terms to Your New Programs
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632 | the "copyright" line and a pointer to where the full notice is found.
633 |
634 | A fast, clean, typesafe, C++11, header only, Entity Component System
635 | Copyright (C) 2015 Robin Grönberg
636 |
637 | This program is free software: you can redistribute it and/or modify
638 | it under the terms of the GNU General Public License as published by
639 | the Free Software Foundation, either version 3 of the License, or
640 | (at your option) any later version.
641 |
642 | This program is distributed in the hope that it will be useful,
643 | but WITHOUT ANY WARRANTY; without even the implied warranty of
644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
645 | GNU General Public License for more details.
646 |
647 | You should have received a copy of the GNU General Public License
648 | along with this program. If not, see .
649 |
650 | Also add information on how to contact you by electronic and paper mail.
651 |
652 | If the program does terminal interaction, make it output a short
653 | notice like this when it starts in an interactive mode:
654 |
655 | OpenEcs Copyright (C) 2015 Robin Grönberg
656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
657 | This is free software, and you are welcome to redistribute it
658 | under certain conditions; type `show c' for details.
659 |
660 | The hypothetical commands `show w' and `show c' should show the appropriate
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664 | You should also get your employer (if you work as a programmer) or school,
665 | if any, to sign a "copyright disclaimer" for the program, if necessary.
666 | For more information on this, and how to apply and follow the GNU GPL, see
667 | .
668 |
669 | The GNU General Public License does not permit incorporating your program
670 | into proprietary programs. If your program is a subroutine library, you
671 | may consider it more useful to permit linking proprietary applications with
672 | the library. If this is what you want to do, use the GNU Lesser General
673 | Public License instead of this License. But first, please read
674 | .
675 |
676 |
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/README.md:
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1 | # OpenEcs - A fast, clean, typesafe, C++11, header only, Entity Component System
2 |
3 | [](https://travis-ci.org/Gronis/OpenEcs) [](https://ci.appveyor.com/project/Gronis/openecs) [](https://gitter.im/Gronis/OpenEcs)
4 |
5 | ## What is OpenEcs?
6 | Open Ecs is an Entity Component System that uses metaprogramming, cache coherency, and other useful tricks to maximize
7 | performance and configurability. It is written in c++11 without further dependencies.
8 |
9 | NOTE: OpenEcs is still in beta and usage with the library might change. If you need a complete ECS library for a serious
10 | project, I suggest looking further. I want more stuff like custom component allocators and perhaps a compile time
11 | configurable EntityManager and SystemManager. Some way to handle events might be useful to include.
12 | Though, I don't want to bloat the lib with too much features. Let me know what you think and what is missing, I hope you enjoy using OpenEcs.
13 |
14 | ## Why OpenEcs?
15 | I authored OpenEcs after using other ECS libraries. The main reason for this was that I wanted to write my own, and it
16 | wasn't supposed to become its own library. As I progressed, I thought it might be worth releasing it to the public as it
17 | slightly became a library with a different approach than the others.
18 |
19 | OpenECS focuses on clean and understandable code that compiles to something with good performance, with good defaults, but still providing the ability to configure alternative behaviours when necessary.
20 |
21 | ## Installation
22 | Just [Download](https://github.com/Gronis/OpenEcs/raw/master/single_include/ecs.h) the header and include it into your project.
23 | Make sure to enable c++11 when compiling. (-std=c++11 or -std=c++0x)
24 |
25 | ## Support
26 | OpenEcs support all mainstream compilers:
27 | * gcc (tested with v4.8)
28 | * clang
29 | * MSVC (Visual Studio 2015)
30 |
31 | ## Standard Features:
32 | The first thing you need is somewhere to store the entities. This is called the EntityManager and is created like this:
33 | ```cpp
34 | using namespace ecs;
35 | EntityManager entities;
36 | ```
37 |
38 | Once the EntityManager is created. Adding entitites can be done like this
39 |
40 | ```cpp
41 | EntityManager entities;
42 |
43 | //Create one entity;
44 | Entity entity = entities.create();
45 |
46 | //Create 100 entities
47 | vector new_entities = entities.create(100);
48 |
49 | //Create 100 entities and do something with them
50 | entities.create(100, [] (Entity entity){
51 | //Do something with the added entity
52 | });
53 | ```
54 |
55 | ### Adding Components to entities
56 | Adding components to entities is easy. But first we must define a Component. A Component can be any class or struct.
57 |
58 | ```cpp
59 |
60 | struct Health{
61 | Health(int value) : value(value)
62 | int value;
63 | };
64 |
65 | EntityManager entities;
66 |
67 | //Create one entity;
68 | Entity entity = entities.create();
69 |
70 | //Add health component with a value of 10 to the entity
71 | entity.add(10);
72 |
73 | //The set function can be used even if health was added before.
74 | entity.set(20);
75 |
76 | //ERROR! Add only works when it doesn't already exists.
77 | entity.add(10);// <- Assert failure, component already added
78 | ```
79 |
80 | NOTE: In order to call the "set" method, the copy constructor for the component should not be deleted, as the copy constructor will be used if the entity already has a component of that type. However, "add" does not have this requirement, since we know that the entity does not have that component beforehand, and components without the copy constructor can be added.
81 |
82 | ```cpp
83 | struct Health{
84 | Health(const & Health) = delete; //<-- removed copy constructor
85 | };
86 |
87 | Entity entity = entities.create();
88 | entity.set(10); //<-- compiler error, copy constructor deleted
89 |
90 | entity.add(10); //<-- OK
91 | ```
92 |
93 |
94 | To reduce boilerplate code, the constructor is optional. If setting variables is then only thing that happens in the constructor, leave it be.
95 |
96 | ```cpp
97 | struct Health{
98 | int value;
99 | };
100 |
101 | Entity entity = entities.create();
102 | entity.add(10);
103 |
104 | ```
105 | NOTE: This is provided by using uniform initialization, which means that the arguments must be exactly the same as the member variables of the component
106 |
107 | ```cpp
108 | entity.add(10.0f);// <- does not work, since float is not int
109 | ```
110 |
111 | There is also a way to add components at the same time when creating an Entity by using the "create_with" method:
112 |
113 | ```cpp
114 | entities.create_with(10, 5); //Adds health = 10 and mana = 5
115 | //OR
116 | entities.create_with(Health(10), Mana(5)); //Same as above.
117 | //This is the same as doing this:
118 | Entity entity = entity.create();
119 | entity.add(10);
120 | entity.add(5);
121 | ```
122 |
123 | Which one to use is up to you, though adding the components with one line gives information to the EntityManager
124 | what components are comming, and the location of the entity in memory can be probably be better.
125 |
126 | ### Accessing Components from entities
127 | Accessing components is just as easy as adding them
128 |
129 | ```cpp
130 | //Set health component with a value of 10 to the entity
131 | entity.set(10);
132 |
133 | //Access the Health Component
134 | Health& health = entity.get();
135 | health.value = 3;
136 |
137 | //NOTE, you should use reference, not value.
138 | //Otherwise, the components will be copied and
139 | //any change made to it will not be registered
140 | //on the actual component
141 |
142 | //NOTE: Do not use (unless you know what you are doing)
143 | Health health = entity.get();
144 | health.value = 3;// <- does not change health of entity,
145 | // because variable is copied
146 |
147 | ```
148 | Accessing a component which does not exist on a specified entity will trigger a runtime assertion. To check if an entity has a specified component, use the "has" function.
149 |
150 | ```cpp
151 | Entity entity = entities.create();
152 | bool has_health = entity.has(); //Returns false
153 |
154 | entity.add(10);
155 | has_health = entity.has(); //Returns true
156 |
157 | ```
158 |
159 | ### Removing Entities and Components
160 |
161 | Destroying an entity can be done using the destroy method
162 | ```cpp
163 | Entity entity = entities.create();
164 | entity.destroy();
165 | //or
166 | entities.destroy(entity);
167 | ```
168 |
169 | Removing Components is done by using the remove function
170 | ```cpp
171 | Entity entity = entities.create();
172 | entity.add(0);
173 | entity.remove();
174 | ```
175 | Destroying an entity removes all components and calls their destructors. it also opens that memory slot for another entity to take its place.
176 |
177 | When an entity is destroyed. It is no longer valid, and any action used with it should not work
178 | ```cpp
179 | entity.destroy();
180 | //Does not work
181 | entity.add(0); // <- triggers runtime assertion, Entity invalid
182 |
183 | //Check if entity is valid
184 | bool is_valid = entity.is_valid();
185 | ```
186 |
187 | To track if an entity is valid. OpenEcs associates each entity with a version when accessed from the EntityManager. Whenever an entity is destroyed, the version for that Entity changes, and all entities with the old versions are invalid, as they no longer exists.
188 |
189 | ### Iterating through the EntityManager
190 | To access entities with certain components. There is a "with" function that looks like this
191 |
192 | ```cpp
193 | EntityManager entities;
194 |
195 | //Iterate through the entities, grabbing each
196 | //entity with Health and Mana component
197 | for(Entity entity : entities.with()){
198 | entity.get(); //Do things with health
199 | entity.get(); //Do things with mana
200 | }
201 |
202 | //There is also a functional style iteration that works
203 | //with a provided lambda.
204 | entities.with([](Health& health, Mana& mana){
205 | health.value = 2; //Do stuff
206 | });
207 |
208 | //If you need the entity, include it as well
209 | entities.with([](Health& health, Mana& mana, Entity entity){
210 | health.value = 2; //Do stuff
211 | entity.remove();
212 | });
213 |
214 | ```
215 |
216 | NOTE, use reference, not values as parameters. (with the exception of Entity). Otherwise, the components will be copied and any change made to it will not be registered on the actual component.
217 |
218 |
219 | ```cpp
220 | //Don't forget to use references ----
221 | // | \
222 | // v v
223 | entities.with([](Health & health, Mana & mana){ });
224 |
225 | ```
226 |
227 | ### Systems
228 | Systems define our behavior. The SystemManager provided by OpenEcs is very simple and is just a wrapper around an interface with an update function, together with the entities.
229 |
230 | First we define our SystemManager
231 |
232 | ```cpp
233 | EntityManager entities;
234 | //We must provide what entities we like to work with
235 | SystemManager systems(entities);
236 | ```
237 |
238 | Then we create a system class.
239 | Any new system class must inherit the System class like this:
240 |
241 | ```cpp
242 | class RemoveCorpsesSystem : public System{
243 | public:
244 | void update(float time) override {
245 | // Get the entity manager using entities() function
246 | for(auto entity : entities().with()){
247 | if(entity.get().value <= 0){
248 | //Destroy the entity
249 | entity.destroy();
250 | }
251 | }
252 | }
253 | };
254 |
255 | EntityManager entities;
256 | SystemManager systems(entities);
257 |
258 | systems.add( /*Provide any constructor arguments*/ );
259 |
260 | //Here we update all systems
261 | float deltaTime = 1;
262 | systems.update(deltaTime); //Updates RemoveCorpsesSystem
263 |
264 | //We can also remove systems when we do not need them
265 | systems.remove();
266 | systems.update(deltaTime); //Does not updates any system
267 |
268 | ```
269 |
270 | The systems are updated in the same order as they are added.
271 |
272 | ### Error handling
273 | Any runtime or compile-time error should be handled by static or runtime assertions.
274 |
275 | ## Extra features
276 | Aside from the normal usage of bitmasks for Component recognition and storing components in a vector for cache
277 | coherency, OpenEcs has some extra features.
278 |
279 | ### EntityAlias that enables object oriented interaction.
280 |
281 | As an object oriented programmer, the ability to encapsulate the implementation as much as possible is desired. By using
282 | EntityAlias, an Entity can be wrapped inside these, witch then define all functions needed. then, the systems can
283 | interact with these EntityAliases instead of the entity. This takes no extra performance, and creates an abstraction
284 | later between actual ECS implementation and the desired action.
285 |
286 | Defining an EntityAlias
287 | ```cpp
288 | class Actor : public EntityAlias{
289 | public:
290 | //here we can hide the implementation details of how the components
291 | //are used by the entity, and provide ordinary functions instead.
292 | void kill(){
293 | get().value = 0;
294 | }
295 |
296 | bool attack(Entity target){
297 | if(!has()){
298 | add(target);
299 | return true;
300 | }
301 | return false;
302 | }
303 | };
304 | ```
305 |
306 | NOTE: An EntityAlias class cannot define new member variables. It is only a wrapper between the
307 | entity and the actual components. If new data needs to be associated with the entity, introduce
308 | new components instead
309 |
310 | The EntityAlias assumes that the entity has all components provided by the inheritance.
311 | We can get every entity that can be associated as an Actor (all entities with Health and Name in this case) by using the
312 | "fetch_every" function, or a from a single Entity using the "as" function.
313 |
314 | ```cpp
315 | EntityManager entities;
316 |
317 | Entity entity = entities.create();
318 | entity.add(0);
319 | entity.add("");
320 |
321 | // Access all entities that has all required components that an Actor has
322 | for(Actor actor : entities.fetch_every()){
323 | actor.kill(); //For example
324 | }
325 | //or with lambda
326 | entities.fetch_every([](Actor& actor){
327 | actor.kill();
328 | });
329 |
330 | //Access one entity as EntityAlias
331 | Actor actor = entity.as();
332 | ```
333 |
334 | The sweetness with using the "fetch_every" function is that it basically generates the same code as this:
335 |
336 | ```cpp
337 | EntityManager entities;
338 |
339 | for(auto entity : entities.with()){
340 | entity.get().value = 0; // <- same as actor.kill();
341 | }
342 | ```
343 |
344 | This is very useful, as we get another abstraction layer without giving up performance.
345 |
346 |
347 | NOTE: the "as" function will result in a runtime assertion error if the
348 | entity does not have the required components (Health and Name in this case)
349 |
350 | Use "is" function to test if entity can be observed as an Actor
351 |
352 | ```cpp
353 | // The "is" function will test if entity has all required components for Actor
354 | if(entity.is()){ // <- same as entity.has()
355 | Actor actor = entity.as(); // <- Safe to Access Entity Alias
356 | }
357 | ```
358 |
359 |
360 | ### Creating entities by using EntityAlias
361 | By defining a constructor for the EntityAlias. We can use the create function from the EntityManager
362 | like this:
363 |
364 | ```cpp
365 | class Actor : public EntityAlias{
366 | // ^ ^
367 | // \_____|
368 | public:// |
369 | Actor(int health, std::string name){// |
370 | add(health);// |
371 | add(name);// |
372 | //Make sure to add all required components.
373 | //If any required component is not added,
374 | //this will cause a runtime assertion failure
375 |
376 | //it is also important to use "add" instead of "set"
377 | //as "set" assumes that all required components are
378 | //already set for this entity (Since they are
379 | //required).
380 | }
381 | };
382 | ```
383 |
384 | Once we have the EntityAlias constructor, we can create
385 | an entity using the "create" function.
386 |
387 | ```cpp
388 | EntityManager entities;
389 |
390 | //Create an actor with 10 health and named Evil Dude
391 | Actor actor = entities.create(10, "Evil Dude");
392 |
393 | ```
394 | This results in a useful factory method for any EntityAlias. Another good thing is that what an Entity is, is defined by
395 | its components, and enables entities to be several things at the same time, without using hierarchy (Which is the idea
396 | behind Entity Component Systems).
397 |
398 | ### Wait a bit...
399 |
400 | You might start thinking "If all components should be added anyway. Why is the constructor needed?" I started thinking that too, and added a standard behavior.
401 |
402 | Considering the following code:
403 |
404 | ```cpp
405 | //Components
406 | struct Name {
407 | str::string value;
408 | };
409 | struct Height {
410 | int value;
411 | };
412 | struct Weight {
413 | int value;
414 | };
415 |
416 | //Since components have optional constructors, We can type like this
417 | //to create an Actor (Entity with Name, Height and Weight)
418 | auto entity = entities.create();
419 | entity.add("Darth Vader");
420 | entity.add(180);
421 | entity.add(75);
422 |
423 | //But we want to use the EntityAlias class, because we know what an Actor is.
424 | //However, we don't want to write the constructor, because enough is specified
425 | //for the library to "figure out" how to create an Actor after specifying what
426 | //components it has. Therefore, we leave out the constructor.
427 | class Actor : public EntityAlias {};
428 |
429 | //And then create an Actor like this
430 | entities.create("Darth Vader", 180, 75);
431 | // ^ ^ ^
432 | // | | |
433 | // Assumes constructor for Name / |
434 | // Assumes constructor for Height ---´ /
435 | // Assumes constructor for Weight -------´
436 |
437 | //create assumes that each parameter can add
438 | //required components with that single argument.
439 | class Actor : public EntityAlias {
440 | //No constructor means the same thing as this constructor
441 | Actor(std::string name, int height, int weight){
442 | add(name);
443 | add(height);
444 | add(weight);
445 | }
446 | };
447 | ```
448 |
449 | NOTE: This does not work when a required components needs more than one argument when creating the object. This is true with components like 2D velocity, and 2D position:
450 |
451 | ```cpp
452 | //Components with MORE than 1 member variable
453 | struct Velocity{ int x,y; };
454 | struct Position{ int x,y; };
455 |
456 | //EntityAlias
457 | struct Movable : EntityAlias{};
458 |
459 | entities.create(/*What to write here?*/);
460 |
461 | //In order to create a movable without providing a constructor
462 | //We must write like this.
463 | entities.create(Position{0,0}, Velocity{0,0});
464 | //This calls the standard copy constructor for Position and
465 | //Velocity component.
466 |
467 | //If we want to be able to write something like this:
468 | entities.create(0,0,0,0);
469 | //We need to provide the following constructor, since
470 | //there is not enough information specified for the
471 | //library to understand how to add create a Movable.
472 | struct Movable : EntityAlias{
473 | Movable(int posX, int posY, int velX, int velY){
474 | add(posX, posY);
475 | add(velX, velY);
476 | }
477 | };
478 | ```
479 |
480 | Hopefully, this should help with quick creation of components and EntityAliases without typing "boilerplate code" for the lazy people (like me), while still allowing the flexibility of defining your own constructors when necessary.
481 |
482 |
483 | ### Override operators
484 | It would be useful if the components override some basic operators for cleaner code.
485 | ```cpp
486 | //Using == operator of component class
487 | bool health_equals_mana =
488 | entity.get() == entity.get();
489 |
490 | //If no operators are defined, we must write it like this
491 | bool health_equals_mana =
492 | entity.get().value == entity.get().value;
493 | ```
494 | However, defining operators for each component is just useless boilerplate code can be very anoying, time consuming, and difficult to write. If the component only has one property, in the case of Health in this example. There is a class called Property\ which overrides useful operators. The Component class may extend this class to inherit some basic operators.
495 |
496 | ```cpp
497 | struct Health : Property{
498 | //Define constructor like this
499 | Health(int value) : Property(value){};
500 | //Or like this
501 | Health(int value){
502 | this->value = value;
503 | };
504 | };
505 |
506 | // Or skip the constructor entirely, like with usual components.
507 | // However the assignment operator will not work without
508 | // a given constructor.
509 | struct Health : Property{};
510 |
511 | //Needs a constructor for assignment like this to work
512 | entity.get() = 4;// <- needs a constructor to enable assignment
513 |
514 | ```
515 |
516 | Now we should have some useful operator implementations for the health component which enables cleaner code
517 |
518 | ```cpp
519 | // operator >
520 | if(entity.get() > 10){
521 |
522 | }
523 | // without using operator >
524 | if(entity.get().value > 10){
525 |
526 | }
527 | ```
528 | NOTE: Remember that any class can be a component, and that it is optional to use Property\, as overriding operators is not always desired. For those who does not what to use overridden operators, leave out the Property\ class.
529 |
530 | ### Memory
531 |
532 | The memory for components and entities are handled manually by OpenEcs. Entities are nothing more than a placeholder with its ID, and a pointer to its EntityManager. Entities are not stored, but created when returned from the API.
533 |
534 | The ID for an entity is its index (Where its located) and a version (When reusing old indexes for removed entities). All versions for an Entity is stored in a std::vector continuously in memory, as a number.
535 |
536 | Every component type gets its own id and a component mask, which tracks what components each entity has. These masks are placed in a std::vector, like the versions. Each bit represents if an entity has a component. By default, the component mask size is 64bits, which means that the max number of component types that can be used with OpenEcs is 64. This can be changed with a define like this BEFORE including the header. In this example, each component mask will be 128bits, and can therefore, OpenEcs will be able to keep track of 128 different component types.
537 |
538 | ```cpp
539 | #define ECS_MAX_NUM_OF_COMPONENTS 128
540 | #include "ecs/ecs.h"
541 | ```
542 |
543 |
544 |
545 | Each component type is handled by a component manager, which is basically a memory pool. The chunk size for a component manager's memory pool is 64 * s bytes, where s is the size of the component type for the component manager. The number 64 is there because one chunk should at least fit on one or more cachelines in memory. There is no point in making it larger, and smaller reduces performance. Just as the versions, each component is located at the index for its entity ID.
546 |
547 |
548 |
549 | The EntityManager allocates memory for each entity to have every component. This might sound stupid, but once memory is allocated, not using it does not cost any cpu time, and we still want the opportunity to add any component to an entity. However it's not cheap to load memory into the cpu. Therefore, the EntityManager tries to put "similar" entities together in memory when they are created. More about this can be read in the Performance section.
550 |
551 |
552 |
553 | ### Performance
554 |
555 | On my Apple MBP Retina 13" 2014 computer, this is some performance tests using 10 000 000 entities with some components
556 | attached:
557 |
558 | | Operation | Time |
559 | |-------------------------------------------------------|---------------|
560 | | create() | 0.38s |
561 | | create(10M) | 0.17257s |
562 | | destroy() | 0.16733s |
563 | | normal for-loop with if-case | 0.00652s |
564 | | iterating using with for-loop (without unpacking) | 0.00847s |
565 | | iterating using with for-loop (unpack one component) | 0.01125s |
566 | | iterating using with lambda (unpack one component) | 0.01125s |
567 | | iterating using with for-loop (unpack two components) | 0.01600s |
568 | | iterating using with lambda (unpack two components) | 0.01600s |
569 | | iterating using fetch_every for-loop | 0.00812s |
570 | | iterating using fetch_every lambda | 0.00812s |
571 |
572 | To improve performance, there are some guidelines:
573 |
574 | Create entities by using EntityAlias or with "create_with\" function, as this gives the EntityManager an idea were to put the entities. The EntityManager tries to clump similar entities together in memory, in order to reduce cache misses when loading memory into the cache CPU memory. When creating entities like this:
575 |
576 | ```cpp
577 | // The EntityManager has no idea what components are coming
578 | // and and will probably put this entity near other entities
579 | // that don't have similar components.
580 | Entity e = entities.create();
581 | e.add();
582 | e.add();
583 | ```
584 |
585 | By doing this instead:
586 |
587 | ```cpp
588 | // Here the EntityManager knows what components the Entity will
589 | // have, and will put it close to other entities which also had
590 | // these components when created.
591 | Entity e = entities.create_with(/* Args here */);
592 | //or
593 | auto e = entities.create(/* Constructor args for SomeEntityAlias here */);
594 | ```
595 |
596 | NOTE: Of course this means that adding or removing components from entities will result in cache misses anyway. This cannot be resolved, unless the entity components is moved in memory, which breaks the idea of that the index is part of the Entity ID. However, it is most likely that entities will retain most of its components over its lifecycle, and therefore, providing this information should result in a performance boost.
597 |
598 |
599 | To improve performance iterate by using auto when iterating with a for loop
600 |
601 | ```cpp
602 | for(auto entity : entities.with()){
603 | // ^
604 | // \
605 | // ` The type here will not become Entity, it will become EntityAlias.
606 | // It will only use the normal Entity class if you tell it to.
607 | }
608 |
609 | ```
610 | When you use the function "get\" on the Entity object,we need to perform some runtime checks. If you are using EntityAlias\, the compiler assumes that the entity has Health and Name components, and bypasses this check when accessing the component. We already do this runtime check when we iterate through the list. Why do it again?
611 |
612 | ```cpp
613 | for(auto entity : entities.with()){
614 | entity.get(); // <- No runtime check. Fast
615 | entity.get(); // <- Runtime check required.
616 | }
617 |
618 | ```
619 |
620 | Or just use the lambda version of "with" or "fetch_every" function with your own EntityAliases, and you
621 | are good to go!
622 |
623 | ```cpp
624 | entities.with([](Health& health, Name& name){ });
625 | //or
626 | entities.fetch_every([](Actor actor){ });
627 |
628 | ```
629 |
630 | ## A complete example
631 | This examples illustrates two spellcasters: Alice and Bob, and their fight to the death. Prints the winner and remaining
632 | health and mana.
633 |
634 | ```cpp
635 | #include
636 | #include "ecs/ecs.h"
637 |
638 | using namespace ecs;
639 |
640 | //Components as properties, we skip defining a constructor, since we
641 | //don't do anything unusual.
642 | struct Health : Property{};
643 | struct Mana : Property{};
644 | struct Name : Property{};
645 |
646 | struct Spellcaster : public EntityAlias{
647 | //We don't need to define a constructor since all of
648 | //our components only have 1 member.
649 | bool isOom(){
650 | return get() == 0;// <- override == operator
651 | }
652 |
653 | bool isAlive(){
654 | return get() > 0;
655 | }
656 | void castSpell(Spellcaster& target){
657 | if(!isOom()){
658 | --get();
659 | --target.get();
660 | }
661 | }
662 | };
663 |
664 | class RemoveCorpsesSystem : public System{
665 | public:
666 | void update(float time) override {
667 | //Method 1
668 | //Any health entity
669 | entities().with([](Health& health, Entity entity){
670 | if(health <= 0){
671 | entity.destroy();
672 | }
673 | });
674 | //Method 2
675 | //Any spellcaster that is dead
676 | entities().fetch_every([](Spellcaster& spellcaster){
677 | if(!spellcaster.isAlive()){
678 | spellcaster.destroy();
679 | }
680 | });
681 | }
682 | };
683 |
684 | class CastSpellSystem : public System{
685 | public:
686 | void update(float time) override {
687 | entities().fetch_every([&] (Spellcaster& spellcaster1){
688 | entities().fetch_every([&] (Spellcaster& spellcaster2){
689 | if(spellcaster1 != spellcaster2){
690 | spellcaster1.castSpell(spellcaster2);
691 | }
692 | });
693 | });
694 | }
695 | };
696 |
697 | class GiveManaSystem : public System{
698 | public:
699 | void update(float time) override {
700 | entities().fetch_every([] (Spellcaster& spellcaster){
701 | if(spellcaster.isOom()) spellcaster.set(1337);
702 | });
703 | }
704 | };
705 |
706 | class Game{
707 | public:
708 | Game() : systems(entities) {}
709 | void run(){
710 | systems.add();
711 | systems.add();
712 | systems.add();
713 | entities.create("Alice", 8, 12);
714 | entities.create("Bob", 12, 8);
715 | while(entities.count() > 1) systems.update(1);
716 | entities.with([] (Name& name, Health& health, Mana& mana){
717 | std::cout << name << " won!" << std::endl;
718 | std::cout << "Health: " << health << std::endl;
719 | std::cout << "Mana: " << mana << std::endl;
720 | });
721 | }
722 |
723 | private:
724 | EntityManager entities;
725 | SystemManager systems;
726 | };
727 |
728 | int main(){
729 | Game game;
730 | game.run();
731 | }
732 | ```
733 |
734 | Output:
735 | ```
736 | Bob won!
737 | Health: 4
738 | Mana: 1337
739 | ```
740 |
741 | ## License
742 | Copyright (C) 2015 Robin Grönberg
743 |
744 | This program is free software: you can redistribute it and/or modify
745 | it under the terms of the GNU General Public License as published by
746 | the Free Software Foundation, either version 3 of the License, or
747 | (at your option) any later version.
748 |
749 | This program is distributed in the hope that it will be useful,
750 | but WITHOUT ANY WARRANTY; without even the implied warranty of
751 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
752 | GNU General Public License for more details.
753 |
754 | You should have received a copy of the GNU General Public License
755 | along with this program. If not, see .
756 |
--------------------------------------------------------------------------------
/examples/example.cpp:
--------------------------------------------------------------------------------
1 | /// --------------------------------------------------------------------------
2 | /// Copyright (C) 2015 Robin Grönberg
3 | ///
4 | /// This program is free software: you can redistribute it and/or modify
5 | /// it under the terms of the GNU General Public License as published by
6 | /// the Free Software Foundation, either version 3 of the License, or
7 | /// (at your option) any later version.
8 | ///
9 | /// This program is distributed in the hope that it will be useful,
10 | /// but WITHOUT ANY WARRANTY; without even the implied warranty of
11 | /// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 | /// GNU General Public License for more details.
13 | ///
14 | /// You should have received a copy of the GNU General Public License
15 | /// along with this program. If not, see .
16 |
17 | #include
18 | #include "ecs.h"
19 | #include "ecs.h"
20 |
21 | using namespace ecs;
22 |
23 | //Components as properties, we skip defining a constructor, since we
24 | //don't do anything unusual.
25 |
26 | struct Health : Property{};
27 | struct Mana : Property{};
28 | struct Name : Property{};
29 |
30 | struct Spellcaster : public EntityAlias{
31 | //We don't need to define a constructor since all of
32 | //our components only have 1 member.
33 | bool isOom(){
34 | return get() == 0;// <- override == operator
35 | }
36 |
37 | bool isAlive(){
38 | return get() > 0;
39 | }
40 | void castSpell(Spellcaster& target){
41 | if(!isOom()){
42 | --get();
43 | --target.get();
44 | }
45 | }
46 | };
47 |
48 | class RemoveCorpsesSystem : public System{
49 | public:
50 | void update(float time) override {
51 | //Method 1
52 | //Any health entity
53 | entities().with([](Health& health, Entity entity){
54 | if(health <= 0){
55 | entity.destroy();
56 | }
57 | });
58 | //Method 2
59 | //Any spellcaster that is dead
60 | entities().fetch_every([](Spellcaster& spellcaster){
61 | if(!spellcaster.isAlive()){
62 | spellcaster.destroy();
63 | }
64 | });
65 | }
66 | };
67 |
68 | class CastSpellSystem : public System{
69 | public:
70 | void update(float time) override {
71 | entities().fetch_every([&] (Spellcaster& spellcaster1){
72 | entities().fetch_every([&] (Spellcaster& spellcaster2){
73 | if(spellcaster1 != spellcaster2){
74 | spellcaster1.castSpell(spellcaster2);
75 | }
76 | });
77 | });
78 | }
79 | };
80 |
81 | class GiveManaSystem : public System{
82 | public:
83 | void update(float time) override {
84 | entities().fetch_every([] (Spellcaster& spellcaster){
85 | if(spellcaster.isOom()) spellcaster.set(1337);
86 | });
87 | }
88 | };
89 |
90 | class Game{
91 | public:
92 | Game() : systems(entities) {}
93 | void run(){
94 | systems.add();
95 | systems.add();
96 | systems.add();
97 | entities.create("Alice", 8, 12);
98 | entities.create("Bob", 12, 8);
99 | while(entities.count() > 1) systems.update(1);
100 | entities.with([] (Name& name, Health& health, Mana& mana){
101 | std::cout << name << " won!" << std::endl;
102 | std::cout << "Health: " << health << std::endl;
103 | std::cout << "Mana: " << mana << std::endl;
104 | });
105 | }
106 |
107 | private:
108 | EntityManager entities;
109 | SystemManager systems;
110 | };
111 |
112 | int main(){
113 | Game game;
114 | game.run();
115 | }
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/include/BaseEntity.h:
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1 | //
2 | // Created by Robin Grönberg on 05/12/15.
3 | //
4 |
5 | #ifndef OPENECS_BASEENTITY_H
6 | #define OPENECS_BASEENTITY_H
7 |
8 | #include "Entity.h"
9 | #include "EntityManager.h"
10 |
11 |
12 | namespace ecs {
13 |
14 | namespace details {
15 |
16 | class BaseEntity {
17 | public:
18 | inline BaseEntity(const Entity &entity);
19 | protected:
20 | inline BaseEntity();
21 | inline BaseEntity(EntityManager* manager);
22 | inline BaseEntity(const BaseEntity &other);
23 | inline BaseEntity& operator=(const BaseEntity& other) { entity_ = other.entity_; return *this; }
24 |
25 | inline EntityManager &entities() { return *manager_; }
26 | inline Entity &entity() { return entity_; }
27 | inline EntityManager const& entities() const { return *manager_; }
28 | inline Entity const& entity() const { return entity_; }
29 | private:
30 | union {
31 | EntityManager *manager_;
32 | Entity entity_;
33 | };
34 | }; //BaseEntity
35 |
36 | } // namespace details
37 |
38 | } // namespace ecs
39 |
40 | #include "BaseEntity.inl"
41 |
42 | #endif //OPENECS_BASEENTITY_H
43 |
--------------------------------------------------------------------------------
/include/BaseEntity.inl:
--------------------------------------------------------------------------------
1 | #include "BaseEntity.h"
2 |
3 | namespace ecs {
4 |
5 | namespace details {
6 |
7 | BaseEntity::BaseEntity(const Entity &entity) : entity_(entity) { }
8 | BaseEntity::BaseEntity() { }
9 | BaseEntity::BaseEntity(EntityManager * manager) : manager_(manager){ }
10 | BaseEntity::BaseEntity(const BaseEntity &other) : entity_(other.entity_) { }
11 |
12 | } // namespace details
13 |
14 | } // namespace ecs
15 |
--------------------------------------------------------------------------------
/include/ComponentManager.h:
--------------------------------------------------------------------------------
1 | #ifndef ECS_COMPONENTMANAGER_H
2 | #define ECS_COMPONENTMANAGER_H
3 |
4 | #include "Defines.h"
5 | namespace ecs{
6 |
7 | // Forward declarations
8 | class EntityManager;
9 |
10 | namespace details{
11 |
12 | // Forward declarations
13 | class BaseProperty;
14 |
15 | ///-----------------------------------------------------------------------
16 | /// global function for creating a component at a specific location
17 | ///-----------------------------------------------------------------------
18 | template
19 | auto create_component(void* ptr, Args && ... args) ->
20 | typename std::enable_if::value, C&>::type;
21 |
22 | // Creating a component that doesn't have ctor, and is not a property -> create using uniform initialization
23 | template
24 | auto create_component(void* ptr, Args && ... args) ->
25 | typename std::enable_if::value &&
26 | !std::is_base_of::value, C&>::type;
27 |
28 | // Creating a component that doesn't have ctor, and is a property -> create using underlying Property ctor
29 | template
30 | auto create_component(void* ptr, Args && ... args) ->
31 | typename std::enable_if<
32 | !std::is_constructible::value &&
33 | std::is_base_of::value, C&>::type;
34 |
35 |
36 | ///---------------------------------------------------------------------
37 | /// Helper class, all ComponentManager are a BaseManager
38 | ///---------------------------------------------------------------------
39 | class BaseManager {
40 | public:
41 | virtual ~BaseManager() { };
42 | virtual void remove(index_t index) = 0;
43 | virtual ComponentMask mask() = 0;
44 | virtual void* get_void_ptr(index_t index) = 0;
45 | virtual void const* get_void_ptr(index_t index) const = 0;
46 | virtual void ensure_min_size(index_t size) = 0;
47 | };
48 |
49 | ///---------------------------------------------------------------------
50 | /// Helper class, This is the main class for holding many Component of
51 | /// a specified type. It uses a memory pool to store the components
52 | ///---------------------------------------------------------------------
53 | template
54 | class ComponentManager: public BaseManager, details::forbid_copies {
55 | public:
56 | ComponentManager(EntityManager &manager, size_t chunk_size = ECS_DEFAULT_CHUNK_SIZE);
57 |
58 | /// Allocate and create at specific index, using constructor
59 | template
60 | C& create(index_t index, Args &&... args);
61 |
62 | /// Remove component at specific index and call destructor
63 | void remove(index_t index);
64 |
65 | /// Access a component given a specific index
66 | C& operator[](index_t index);
67 | C& get(index_t index);
68 | C const& get(index_t index) const;
69 |
70 | /// Access a ptr to a component given a specific index
71 | C* get_ptr(index_t index);
72 | C const* get_ptr(index_t index) const;
73 |
74 | /// Access a raw void ptr to a component given a specific index
75 | void* get_void_ptr(index_t index);
76 | void const* get_void_ptr(index_t index) const;
77 |
78 | // Ensures the pool that at it has the size of at least size
79 | void ensure_min_size(index_t size);
80 |
81 | /// Get the bitmask for the component this ComponentManger handles
82 | ComponentMask mask();
83 |
84 | private:
85 | EntityManager &manager_;
86 | details::Pool pool_;
87 | }; //ComponentManager
88 |
89 | } // namespace details
90 |
91 | } // namespace ecs
92 |
93 | #include "ComponentManager.inl"
94 |
95 | #endif //ECS_COMPONENTMANAGER_H
96 |
--------------------------------------------------------------------------------
/include/ComponentManager.inl:
--------------------------------------------------------------------------------
1 | #include "EntityManager.h"
2 | #include "ComponentManager.h"
3 | #include "Defines.h"
4 |
5 | namespace ecs{
6 |
7 | namespace details{
8 |
9 | template
10 | ComponentManager::ComponentManager(EntityManager &manager, size_t chunk_size) :
11 | manager_(manager),
12 | pool_(chunk_size)
13 | { }
14 |
15 | // Creating a component that has a defined ctor
16 | template
17 | auto create_component(void* ptr, Args && ... args) ->
18 | typename std::enable_if::value, C&>::type {
19 | return *new(ptr) C(std::forward(args)...);
20 | }
21 |
22 | // Creating a component that doesn't have ctor, and is not a property -> create using uniform initialization
23 | template
24 | auto create_component(void* ptr, Args && ... args) ->
25 | typename std::enable_if::value &&
26 | !std::is_base_of::value, C&>::type {
27 | return *new(ptr) C{std::forward(args)...};
28 | }
29 |
30 | // Creating a component that doesn't have ctor, and is a property -> create using underlying Property ctor
31 | template
32 | auto create_component(void* ptr, Args && ... args) ->
33 | typename std::enable_if<
34 | !std::is_constructible::value &&
35 | std::is_base_of::value, C&>::type {
36 | static_assert(sizeof...(Args) <= 1, ECS_ASSERT_MSG_ONLY_ONE_ARGS_PROPERTY_CONSTRUCTOR);
37 | return *reinterpret_cast(new(ptr) typename C::ValueType(std::forward(args)...));
38 | }
39 |
40 | template template
41 | C& ComponentManager::create(index_t index, Args &&... args) {
42 | pool_.ensure_min_size(index + 1);
43 | create_component(get_ptr(index), std::forward(args)...);
44 | return get(index);
45 | }
46 |
47 | template
48 | void ComponentManager::remove(index_t index) {
49 | pool_.destroy(index);
50 | manager_.mask(index).reset(component_index());
51 | }
52 |
53 | template
54 | C &ComponentManager::operator[](index_t index){
55 | return get(index);
56 | }
57 |
58 | template
59 | C &ComponentManager::get(index_t index) {
60 | return *get_ptr(index);
61 | }
62 |
63 | template
64 | C const &ComponentManager::get(index_t index) const {
65 | return *get_ptr(index);
66 | }
67 |
68 | template
69 | C *ComponentManager::get_ptr(index_t index) {
70 | return pool_.get_ptr(index);
71 | }
72 |
73 | template
74 | C const *ComponentManager::get_ptr(index_t index) const {
75 | return pool_.get_ptr(index);
76 | }
77 |
78 | template
79 | void *ComponentManager::get_void_ptr(index_t index) {
80 | return pool_.get_ptr(index);
81 | }
82 |
83 | template
84 | void const *ComponentManager::get_void_ptr(index_t index) const {
85 | return pool_.get_ptr(index);
86 | }
87 |
88 | template
89 | void ComponentManager::ensure_min_size(index_t size){
90 | pool_.ensure_min_size(size);
91 | }
92 |
93 | template
94 | ComponentMask ComponentManager::mask() {
95 | return component_mask();
96 | }
97 |
98 | } // namespace details
99 |
100 | } // namespace ecs
--------------------------------------------------------------------------------
/include/Defines.h:
--------------------------------------------------------------------------------
1 | #ifndef ECS_DEFINES_H
2 | #define ECS_DEFINES_H
3 |
4 | #include
5 |
6 | /// The cache line size for the processor. Usually 64 bytes
7 | #ifndef ECS_CACHE_LINE_SIZE
8 | #define ECS_CACHE_LINE_SIZE 64
9 | #endif
10 |
11 | /// This is how an assertion is done. Can be defined with something else if needed.
12 | #ifndef ECS_ASSERT
13 | #define ECS_ASSERT(Expr, Msg) assert(Expr && Msg)
14 | #endif
15 |
16 | /// The maximum number of component types the EntityManager can handle
17 | #ifndef ECS_MAX_NUM_OF_COMPONENTS
18 | #define ECS_MAX_NUM_OF_COMPONENTS 64
19 | #endif
20 |
21 | /// How many components each block of memory should contain
22 | /// By default, this is divided into the same size as cache-line size
23 | #ifndef ECS_DEFAULT_CHUNK_SIZE
24 | #define ECS_DEFAULT_CHUNK_SIZE ECS_CACHE_LINE_SIZE
25 | #endif
26 |
27 | #define ECS_ASSERT_IS_CALLABLE(T) \
28 | static_assert(details::is_callable::value, \
29 | "Provide a function or lambda expression"); \
30 |
31 | #define ECS_ASSERT_IS_ENTITY(T) \
32 | static_assert(std::is_base_of::value || \
33 | std::is_same::value , \
34 | #T " does not inherit EntityAlias.");
35 |
36 | #define ECS_ASSERT_ENTITY_CORRECT_SIZE(T) \
37 | static_assert(sizeof(details::BaseEntity) == sizeof(T), \
38 | #T " should not include new variables, add them as Components instead."); \
39 |
40 | #define ECS_ASSERT_VALID_ENTITY(E) \
41 | ECS_ASSERT(is_valid(E), "Entity is no longer valid"); \
42 |
43 | #define ECS_ASSERT_IS_SYSTEM(S) \
44 | static_assert(std::is_base_of::value, \
45 | "DirivedSystem must inherit System."); \
46 |
47 | #define ECS_ASSERT_MSG_ONLY_ONE_ARGS_PROPERTY_CONSTRUCTOR \
48 | "Creating a property component should only take 1 argument. " \
49 | "If component should initilize more members, provide a " \
50 | "constructor to initilize property component correctly" \
51 |
52 | namespace ecs{
53 | /// Type used for entity index
54 | using index_t = uint32_t;
55 | /// Type used for entity version
56 | using version_t = uint8_t;
57 |
58 | namespace details{
59 |
60 | /// ComponentMask is a mask defining what components and entity has.
61 | using ComponentMask = std::bitset;
62 |
63 | } // namespace details
64 | } // namespace ecs
65 |
66 | #endif //ECS_DEFINES_H
67 |
--------------------------------------------------------------------------------
/include/Entity.h:
--------------------------------------------------------------------------------
1 | #ifndef ECS_ENTITY_H
2 | #define ECS_ENTITY_H
3 |
4 | #include "Id.h"
5 |
6 | namespace ecs{
7 | ///---------------------------------------------------------------------
8 | /// Entity is the identifier of an identity
9 | ///---------------------------------------------------------------------
10 | ///
11 | /// An entity consists of an id and version. The version is used to
12 | /// ensure that new entities allocated with the same id are separable.
13 | ///
14 | /// An entity becomes invalid when destroyed.
15 | ///
16 | ///---------------------------------------------------------------------
17 | class Entity {
18 | public:
19 | inline Entity(EntityManager *manager, Id id);
20 | inline Entity &operator=(const Entity &rhs);
21 |
22 | inline Id &id() { return id_; }
23 | inline Id const &id() const { return id_; }
24 |
25 | /// Returns the requested component, or error if it doesn't exist
26 | template inline C &get();
27 | template inline C const &get() const;
28 |
29 | /// Set the requested component, if old component exist,
30 | /// a new one is created. Otherwise, the assignment operator
31 | /// is used.
32 | template inline C &set(Args &&... args);
33 |
34 | /// Add the requested component, error if component of the same type exist already
35 | template inline C &add(Args &&... args);
36 |
37 | /// Access this Entity as an EntityAlias.
38 | template inline T &as();
39 | template inline T const &as() const;
40 |
41 | /// Assume that this entity has provided Components
42 | /// Use for faster component access calls
43 | template inline EntityAlias &assume();
44 | template inline EntityAlias const &assume() const;
45 |
46 | /// Removes a component. Error of it doesn't exist
47 | template inline void remove();
48 |
49 | /// Removes all components and call destructors
50 | void inline remove_everything();
51 |
52 | /// Clears the component mask without destroying components (faster than remove_everything)
53 | void inline clear_mask();
54 |
55 | /// Destroys this entity. Removes all components as well
56 | void inline destroy();
57 |
58 | /// Return true if entity has all specified components. False otherwise
59 | template inline bool has();
60 | template inline bool has() const;
61 |
62 | /// Returns whether an entity is an entity alias or not
63 | template inline bool is();
64 | template inline bool is() const;
65 |
66 | /// Returns true if entity has not been destroyed. False otherwise
67 | bool inline is_valid();
68 | bool inline is_valid() const;
69 |
70 | private:
71 | /// Return true if entity has all specified compoents. False otherwise
72 | inline bool has(details::ComponentMask &check_mask);
73 | inline bool has(details::ComponentMask const &check_mask) const;
74 |
75 | inline details::ComponentMask &mask();
76 | inline details::ComponentMask const &mask() const;
77 |
78 | inline static details::ComponentMask static_mask();
79 |
80 | EntityManager *manager_;
81 | Id id_;
82 |
83 | friend class EntityManager;
84 | }; //Entity
85 |
86 | inline bool operator==(const Entity &lhs, const Entity &rhs);
87 | inline bool operator!=(const Entity &lhs, const Entity &rhs);
88 |
89 | } // namespace ecs
90 |
91 | #include "Entity.inl"
92 |
93 | #endif //ECS_ENTITY_H
94 |
--------------------------------------------------------------------------------
/include/Entity.inl:
--------------------------------------------------------------------------------
1 | #include "EntityAlias.h"
2 | #include "EntityManager.h"
3 |
4 | namespace ecs{
5 |
6 | Entity::Entity(EntityManager *manager, Id id) :
7 | manager_(manager),
8 | id_(id)
9 | { }
10 |
11 | Entity &Entity::operator=(const Entity &rhs) {
12 | manager_ = rhs.manager_;
13 | id_ = rhs.id_;
14 | return *this;
15 | }
16 |
17 | template
18 | C &Entity::get() {
19 | return manager_->get_component(*this);
20 | }
21 |
22 | template
23 | C const &Entity::get() const {
24 | return manager_->get_component(*this);
25 | }
26 |
27 | template
28 | C &Entity::set(Args && ... args){
29 | return manager_->set_component(*this, std::forward(args) ...);
30 | }
31 |
32 | template
33 | C &Entity::add(Args && ... args){
34 | return manager_->create_component(*this, std::forward(args) ...);
35 | }
36 |
37 | template
38 | inline T & Entity::as(){
39 | ECS_ASSERT_IS_ENTITY(T);
40 | ECS_ASSERT_ENTITY_CORRECT_SIZE(T);
41 | ECS_ASSERT(has(T::static_mask()), "Entity doesn't have required components for this EntityAlias");
42 | return reinterpret_cast(*this);
43 | }
44 |
45 | template
46 | inline T const & Entity::as() const{
47 | ECS_ASSERT_IS_ENTITY(T);
48 | ECS_ASSERT_ENTITY_CORRECT_SIZE(T);
49 | ECS_ASSERT(has(T::static_mask()), "Entity doesn't have required components for this EntityAlias");
50 | return reinterpret_cast(*this);
51 | }
52 |
53 | /// Assume that this entity has provided Components
54 | /// Use for faster component access calls
55 | template
56 | inline EntityAlias & Entity::assume() {
57 | return as>();
58 | }
59 |
60 | template
61 | inline EntityAlias const & Entity::assume() const {
62 | return as>();
63 | }
64 |
65 | template
66 | void Entity::remove() {
67 | manager_->remove_component(*this);
68 | }
69 |
70 | void Entity::remove_everything() {
71 | manager_->remove_all_components(*this);
72 | }
73 |
74 | void Entity::clear_mask() {
75 | manager_->clear_mask(*this);
76 | }
77 |
78 | void Entity::destroy() {
79 | manager_->destroy(*this);
80 | }
81 |
82 | template
83 | bool Entity::has() {
84 | return manager_->has_component(*this);
85 | }
86 |
87 | template
88 | bool Entity::has() const {
89 | return manager_->has_component(*this);
90 | }
91 |
92 | template
93 | bool Entity::is() {
94 | ECS_ASSERT_IS_ENTITY(T);
95 | ECS_ASSERT_ENTITY_CORRECT_SIZE(T);
96 | return has(T::static_mask());
97 | }
98 |
99 | template
100 | bool Entity::is() const {
101 | ECS_ASSERT_IS_ENTITY(T);
102 | ECS_ASSERT_ENTITY_CORRECT_SIZE(T);
103 | return has(T::static_mask());
104 | }
105 |
106 | bool Entity::is_valid() {
107 | return manager_->is_valid(*this);
108 | }
109 |
110 | bool Entity::is_valid() const {
111 | return manager_->is_valid(*this);
112 | }
113 |
114 | bool Entity::has(details::ComponentMask &check_mask) {
115 | return manager_->has_component(*this, check_mask);
116 | }
117 |
118 | bool Entity::has(details::ComponentMask const &check_mask) const {
119 | return manager_->has_component(*this, check_mask);
120 | }
121 |
122 | details::ComponentMask &Entity::mask() {
123 | return manager_->mask(*this);
124 | }
125 | details::ComponentMask const &Entity::mask() const {
126 | return manager_->mask(*this);
127 | }
128 |
129 | inline bool operator==(const Entity &lhs, const Entity &rhs) {
130 | return lhs.id() == rhs.id();
131 | }
132 |
133 | inline bool operator!=(const Entity &lhs, const Entity &rhs) {
134 | return lhs.id() != rhs.id();
135 | }
136 |
137 | details::ComponentMask Entity::static_mask(){
138 | return details::ComponentMask(0);
139 | }
140 |
141 | } // namespace ecs
--------------------------------------------------------------------------------
/include/EntityAlias.h:
--------------------------------------------------------------------------------
1 | #ifndef ECS_ENTITYALIAS_H
2 | #define ECS_ENTITYALIAS_H
3 |
4 | #include "BaseEntity.h"
5 |
6 | namespace ecs{
7 |
8 | ///---------------------------------------------------------------------
9 | /// EntityAlias is a wrapper around an Entity
10 | ///---------------------------------------------------------------------
11 | ///
12 | /// An EntityAlias makes modification of the entity and other
13 | /// entities much easier when performing actions. It acts solely as an
14 | /// abstraction layer between the entity and different actions.
15 | ///
16 | ///---------------------------------------------------------------------
17 | template
18 | class EntityAlias : public details::BaseEntity {
19 | private:
20 | /// Underlying EntityAlias. Used for creating Entity alias without
21 | /// a provided constructor
22 | using Type = EntityAlias;
23 | template
24 | using is_component = details::is_type;
25 |
26 | public:
27 | inline EntityAlias(const Entity &entity);
28 |
29 | /// Cast to Entity or EntityAlias
30 | inline operator Entity &();
31 | inline operator Entity const &() const;
32 |
33 | inline bool operator==(const Entity &rhs) const;
34 | inline bool operator!=(const Entity &rhs) const;
35 |
36 | inline Id &id();
37 | inline Id const &id() const;
38 |
39 | /// Returns the requested component, or error if it doesn't exist
40 | template inline auto get() -> typename std::enable_if< is_component::value, C &>::type;
41 | template inline auto get() -> typename std::enable_if::value, C &>::type;
42 | template inline auto get() const -> typename std::enable_if< is_component::value, C const &>::type;
43 | template inline auto get() const -> typename std::enable_if::value, C const &>::type;
44 |
45 | /// Set the requested component, if old component exist,
46 | /// a new one is created. Otherwise, the assignment operator
47 | /// is used.
48 | template inline auto set(Args &&... args) ->
49 | typename std::enable_if< is_component::value, C &>::type;
50 | template inline auto set(Args &&... args) ->
51 | typename std::enable_if::value, C &>::type;
52 |
53 | /// Add the requested component, error if component of the same type exist already
54 | template
55 | inline C &add(Args &&... args);
56 |
57 | /// Access this Entity as an EntityAlias.
58 | template inline T &as();
59 | template inline T const &as() const;
60 |
61 | /// Assume that this entity has provided Components
62 | /// Use for faster component access calls
63 | template
64 | inline EntityAlias &assume();
65 |
66 | template
67 | inline EntityAlias const &assume() const;
68 |
69 | /// Removes a component. Error of it doesn't exist. Cannot remove dependent components
70 | template inline auto remove() -> typename std::enable_if< is_component::value, void>::type;
71 | template inline auto remove() -> typename std::enable_if::value, void>::type;
72 |
73 | /// Removes all components and call destructors
74 | inline void remove_everything();
75 |
76 | /// Clears the component mask without destroying components (faster than remove_everything)
77 | inline void clear_mask();
78 |
79 | /// Destroys this entity. Removes all components as well
80 | inline void destroy();
81 | /// Return true if entity has all specified components. False otherwise
82 | template inline bool has();
83 | template inline bool has() const;
84 |
85 | /// Returns whether an entity is an entity alias or not
86 | template inline bool is();
87 | template inline bool is() const;
88 |
89 | /// Returns true if entity has not been destroyed. False otherwise
90 | inline bool is_valid();
91 | inline bool is_valid() const;
92 |
93 | protected:
94 | inline EntityAlias();
95 |
96 | private:
97 | // Recursion init components with argument
98 | template
99 | inline void init_components(Arg arg) {
100 | add(arg);
101 | }
102 |
103 | template
104 | inline void init_components(Arg0 arg0, Arg1 arg1, Args... args) {
105 | init_components(arg0);
106 | init_components(arg1, args...);
107 | }
108 | // Recursion init components without argument
109 | template
110 | inline void init_components() {
111 | add();
112 | }
113 |
114 | template
115 | inline void init_components() {
116 | init_components();
117 | init_components();
118 | }
119 |
120 | template