Introduce new system Pipeline behavior

doc/Tutorial.md

@@ -433,61 +433,44 @@ registry.runSystem<Movement>();
 registry.runSystems();
 ```
 
-By default systems added with `Registry.addSystem()` have the same priority and the order of execution is undefined when calling `Registry.runSystems()`.
-But you can use the system priorities/groups to order them and be able to specify their priority and run a given system group.
+### Pipeline
 
-1. Priority
+By default systems added with `Registry.addSystem()` run in the registration order. But you can use @ref ecstasy::Pipeline "pipelines" to have a better configuration of your systems run order.
 
-   When adding a system to the registry you can add a priority to each system as a second template parameter.
-   Calling `runSystems()` will run the systems in ascending priority order.
+You can group your systems into @ref ecstasy::Pipeline::Phase "phases" which will have an associated priority, being also its identifier.
+Some predefined phases already exists and may be enough for you: @ref ecstasy::Pipeline::PredefinedPhases "PredefinedPhases".
 
-   @warning
-   You can set the same priority for multiple systems but it doesn't ensure they will always run in the same order.
-
-   ```cpp
-       ecstasy::Registry registry;
-
-       registry.addSystem<A, 1>();
-       registry.addSystem<B, 2>();
-       registry.addSystem<C, 3>();
-       registry.addSystem<D, 4>();
-       registry.addSystem<E, 5>();
-       registry.addSystem<F, 6>();
-       registry.runSystems(); // ABCDEF
-       // If you want you can still call systems one by one
-       registry.runSystem<A>(); // A
-   ```
-
-2. Group and masks
+@note
+If you don't specify a phase, the @ref ecstasy::Pipeline::PredefinedPhases::OnUpdate "OnUpdate" is used.
 
-   In fact their is nothing more than the priority value. But using bitmask you can create groups.
+@warning
+I strongly recommend you to use enum types, or const values/macros.
 
-   The following example use 8 bits for the group id and 8 for the system priority.
+```cpp
+    ecstasy::Registry registry;
 
-   ```cpp
-       ecstasy::Registry registry;
-       // Mask of the group part on the priority (bits 8->15)
-       size_t mask = 0xff00;
-       // Groups 'identifiers'
-       const size_t abc = 0x0100;
-       const size_t def = 0x0200;
-
-       // Group 'abc'
-       registry.addSystem<A, abc + 1>();
-       registry.addSystem<B, abc + 2>();
-       registry.addSystem<C, abc + 3>();
-       // Group 'def'
-       registry.addSystem<D, def + 1>();
-       registry.addSystem<E, def + 2>();
-       registry.addSystem<F, def + 3>();
-
-       // The following still calls the systems in the right order because their priorities are still ascending
-       registry.runSystems(); // ABCDEF
-
-       // You can run a system group by sending the group id and the mask
-       registry.runSystems(abc, mask); // ABC
-       registry.runSystems(def, mask); // DEF
-   ```
+    // Default to OnUpdate
+    registry.addSystem<A>();
+    // Explicit OnUpdate, require to be casted as size_t if template parameter
+    registry.addSystem<B, static_cast<size_t>(Pipeline::PedefinedPhases::OnUpdate)>();
+    // Explicit OnLoad but using enum value directly
+    registry.addSystemInPhase<C>(Pipeline::PedefinedPhases::OnLoad);
+    registry.addSystem<D, 250>();
+    registry.addSystem<E, 251>();
+    registry.addSystem<F, Pipeline::PedefinedPhases::OnUpdate>();
+
+
+    // Will run in order:
+    // - OnLoad(100): C
+    // - Custom 250: D
+    // - Custom 251: E
+    // - OnUpdate(400): BCF
+    registry.runSystems();
+    // If you want you can still call systems one by one
+    registry.runSystem<A>(); // A
+    // Or even phase by phase
+    registry.runSystemsPhase<Pipeline::PredefinedPhases::OnUpdate>();
+```
 
 ## Using resources
 

src/ecstasy/registry/Registry.cpp

@@ -24,7 +24,7 @@ namespace ecstasy
         return _builder.build();
     }
 
-    Registry::Registry(bool addEntities)
+    Registry::Registry(bool addEntities) : _pipeline(*this)
     {
         if (addEntities)
             addResource<Entities>();
@@ -81,23 +81,19 @@ namespace ecstasy
             storage.second->erase(entities);
     }
 
+    void Registry::runSystem(const std::type_index &systemId)
+    {
+        _systems.get(systemId).run(*this);
+    }
+
     void Registry::runSystems()
     {
-        for (auto &[type, system] : _systems.getInner())
-            system->run(*this);
+        _pipeline.run();
     }
 
-    void Registry::runSystems(size_t group, size_t mask)
+    void Registry::runSystemsPhase(Pipeline::PhaseId phase)
     {
-        auto &systems = _systems.getInner();
-        auto it = systems.begin();
-
-        // Run all systems with the same group and mask
-        while (it != systems.end()) {
-            if ((it->first.second & mask) == group)
-                it->second->run(*this);
-            ++it;
-        }
+        _pipeline.run(phase);
     }
 
     void Registry::clear()

src/ecstasy/registry/Registry.hpp

@@ -26,6 +26,7 @@
 #include "ecstasy/storages/StorageConcepts.hpp"
 #include "ecstasy/storages/SystemInstances.hpp"
 #include "ecstasy/system/ISystem.hpp"
+#include "ecstasy/system/Pipeline.hpp"
 #include "ecstasy/thread/LockableView.hpp"
 #include "util/Allocator.hpp"
 #include "util/StackAllocator.hpp"
@@ -34,6 +35,7 @@
 #include "concepts/component_type.hpp"
 #include "concepts/queryable_type.hpp"
 #include "ecstasy/registry/concepts/modifier_allocator_size.hpp"
+#include "util/meta/is_size_t_convertible.hpp"
 #include "util/meta/outer_join.hpp"
 
 #ifdef _MSC_VER
@@ -815,8 +817,11 @@ namespace ecstasy
         ///
         /// @brief Add a new system in the registry.
         ///
+        /// @note Call @ref addSystemInPhase to add a system in a specific phase using runtime phase id or an Enum type
+        /// for phase id.
+        ///
         /// @tparam S System to add.
-        /// @tparam Priority System priority. See @ref Registry::runSystems().
+        /// @tparam Phase System phase. See @ref Pipeline.
         /// @tparam Args The type of arguments to pass to the constructor of @b S.
         ///
         /// @param[in] args The arguments to pass to the constructor of @b S.
@@ -828,10 +833,36 @@ namespace ecstasy
         /// @author Andréas Leroux ([email protected])
         /// @since 1.0.0 (2022-10-17)
         ///
-        template <std::derived_from<ISystem> S, size_t Priority = 0, typename... Args>
+        template <std::derived_from<ISystem> S,
+            Pipeline::PhaseId Phase = static_cast<Pipeline::PhaseId>(Pipeline::PredefinedPhases::OnUpdate),
+            typename... Args>
         S &addSystem(Args &&...args)
         {
-            return _systems.emplace<S, Priority>(std::forward<Args>(args)...);
+            return addSystemInPhase<S>(Phase, std::forward<Args>(args)...);
+        }
+
+        ///
+        /// @brief Add a new system in the registry in a specific phase.
+        ///
+        /// @tparam S System to add.
+        /// @tparam T Phase id type. Usually an enum convertible to size_t, or a size_t directly.
+        /// @tparam Args The type of arguments to pass to the constructor of @b S.
+        ///
+        /// @param[in] phaseId Phase id where to add the system.
+        /// @param[in] args The arguments to pass to the constructor of @b S.
+        ///
+        /// @return S& newly created System.
+        ///
+        /// @author Andréas Leroux ([email protected])
+        /// @since 1.0.0 (2024-11-21)
+        ///
+        template <std::derived_from<ISystem> S, util::meta::is_size_t_convertible T, typename... Args>
+        S &addSystemInPhase(T phaseId, Args &&...args)
+        {
+            S &system = _systems.emplace<S>(std::forward<Args>(args)...);
+
+            _pipeline.addSystem(typeid(S), static_cast<size_t>(phaseId));
+            return system;
         }
 
         ///
@@ -1170,32 +1201,36 @@ namespace ecstasy
             _systems.get<S>().run(*this);
         }
 
+        ///
+        /// @brief Run a specific system from the registry.
+        ///
+        /// @param[in] systemId System type index to run.
+        ///
+        /// @author Andréas Leroux ([email protected])
+        /// @since 1.0.0 (2024-11-21)
+        ///
+        void runSystem(const std::type_index &systemId);
+
         ///
         /// @brief Run all systems present in the registry.
         ///
-        /// @note Systems are run in ascending priority order. If two systems have the same priority, run order is
-        /// undefined.
+        /// @note Systems are run in ascending registration order. You can have further control using
+        /// @ref ecstasy::Pipeline::Phase "Phases".
         ///
         /// @author Andréas Leroux ([email protected])
         /// @since 1.0.0 (2022-10-17)
         ///
         void runSystems();
 
         ///
-        /// @brief Run all systems whose priority match the given group.
+        /// @brief Run all systems present in the registry for the given phase.
         ///
-        /// @note The system groups can be seen as an internet network: The @p group 'id' is the network address, the
-        /// @p mask is the network mask and each system priority in the group is a host in the network range.
+        /// @param[in] phase Phase to run the systems for.
         ///
-        /// @note Systems in the group are run in ascending priority order. If two systems have the same priority, run
-        /// order is undefined.
-        ///
-        /// @param[in] group Group priority 'id'.
-        /// @param[in] mask Priority 'id' mask.
         /// @author Andréas Leroux ([email protected])
-        /// @since 1.0.0 (2022-12-19)
+        /// @since 1.0.0 (2024-11-21)
         ///
-        void runSystems(size_t group, size_t mask);
+        void runSystemsPhase(Pipeline::PhaseId phase);
 
         ///
         /// @brief Get a const reference to the storages instances.
@@ -1223,13 +1258,41 @@ namespace ecstasy
             return _storages;
         }
 
+        ///
+        /// @brief Get a reference to the registry pipeline.
+        ///
+        /// @return Pipeline& Reference to the registry pipeline instance.
+        ///
+        /// @author Andréas Leroux ([email protected])
+        /// @since 1.0.0 (2024-11-21)
+        ///
+        [[nodiscard]] constexpr Pipeline &getPipeline() noexcept
+        {
+            return _pipeline;
+        }
+
+        ///
+        /// @brief Get a const reference to the registry pipeline.
+        ///
+        /// @return const Pipeline& Const reference to the registry pipeline instance.
+        ///
+        /// @author Andréas Leroux ([email protected])
+        /// @since 1.0.0 (2024-11-21)
+        ///
+        [[nodiscard]] constexpr const Pipeline &getPipeline() const noexcept
+        {
+            return _pipeline;
+        }
+
       private:
         /// @brief Registry resources.
         Instances<IResource> _resources;
         /// @brief Registry storages.
         Instances<IStorage> _storages;
         /// @brief Registry systems.
-        SystemInstances _systems;
+        Instances<ISystem> _systems;
+        /// @brief System pipeline.
+        Pipeline _pipeline;
 
         /// @internal
         /// @brief Erase all the @p entity components.

src/ecstasy/system/CMakeLists.txt

@@ -3,6 +3,8 @@ set(SRCROOT ${SRCROOT}/system)
 
 set(SRC
     ${SRC}
+    ${INCROOT}/Pipeline.hpp
+    ${SRCROOT}/Pipeline.cpp
     ${INCROOT}/ISystem.hpp
     PARENT_SCOPE
 )