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HierarchyPropagationSystem.ixx File

System for propagating activation state through entity hierarchies. More...

Included Headers​

#include <cassert> #include <utility> #include <vector> #include <helios.engine.common.tags.SystemRole> #include <helios.engine.mechanics.lifecycle.components.Inactive> #include <helios.engine.mechanics.lifecycle.components.Active> #include <helios.engine.runtime.world.UpdateContext> #include <helios.engine.ecs.components.HierarchyComponent> #include <helios.engine.runtime.world.GameWorld> #include <helios.engine.ecs.GameObject> #include <helios.engine.ecs.EntityHandle>

Namespaces Index​

namespacehelios
namespaceengine

Main engine module aggregating core infrastructure and game systems. More...

namespaceecs

Core Entity-Component-System architecture. More...

namespacesystems

Core ECS systems for entity management. More...

Classes Index​

classHierarchyPropagationSystem

Propagates activation state from parent to child entities. More...

Description​

System for propagating activation state through entity hierarchies.

File Listing​

The file content with the documentation metadata removed is:

1/**
2 * @file HierarchyPropagationSystem.ixx
3 * @brief System for propagating activation state through entity hierarchies.
4 */
5module;
6
7#include <cassert>
8#include <utility>
9#include <vector>
10
11export module helios.engine.ecs.systems.HierarchyPropagationSystem;
12
13
14import helios.engine.ecs.EntityHandle;
15import helios.engine.ecs.GameObject;
16
17import helios.engine.ecs.components.HierarchyComponent;
18
19import helios.engine.runtime.world.UpdateContext;
20import helios.engine.runtime.world.GameWorld;
21
22
23import helios.engine.mechanics.lifecycle.components.Active;
24import helios.engine.mechanics.lifecycle.components.Inactive;
25
26
27
28import helios.engine.common.tags.SystemRole;
29
30export namespace helios::engine::ecs::systems {
31
32
33 using namespace helios::engine::ecs;
34
35 /**
36 * @brief Propagates activation state from parent to child entities.
37 *
38 * @details This system processes entities with HierarchyComponent and
39 * propagates their active/inactive state to all descendants. Only root
40 * entities (those without a parent) that are marked dirty trigger
41 * propagation.
42 *
43 * The system runs in two passes:
44 * - Active roots: propagate active state to children
45 * - Inactive roots: propagate inactive state to children
46 */
47 class HierarchyPropagationSystem {
48
49 /**
50 * @brief Recursively updates activation state for an entity and its children.
51 *
52 * @param go The entity to update.
53 * @param active The activation state to apply.
54 */
55 void updateEntityHierarchy(GameObject go, helios::engine::runtime::world::UpdateContext& updateContext, bool active) {
56
57 auto* hc = go.get<helios::engine::ecs::components::HierarchyComponent>();
58 if (!hc) {
59 return;
60 }
61 hc->clearDirty();
62 for (auto child : hc->children()) {
63 if (auto ent = updateContext.find(child)) {
64 ent->setActive(active);
65 updateEntityHierarchy(ent.value(), updateContext, active);
66 }
67 }
68 }
69
70 /**
71 * @brief Temporary storage for root entities pending propagation.
72 */
73 std::vector<GameObject> roots_;
74
75
76 public:
77
78 using EngineRoleTag = helios::engine::common::tags::SystemRole;
79 /**
80 * @brief Processes hierarchy propagation for dirty root entities.
81 *
82 * @param updateContext The current frame's update context.
83 */
84 void update(helios::engine::runtime::world::UpdateContext& updateContext) noexcept {
85
86 for (auto [entity, hc, active] : updateContext.view<
87 helios::engine::ecs::components::HierarchyComponent,
88 helios::engine::mechanics::lifecycle::components::Active
89 >().whereEnabled()) {
90 if (hc->parent() || !hc->isDirty()) {
91 continue;
92 }
93 roots_.push_back(entity);
94 }
95
96 for (auto& entity : roots_) {
97 updateEntityHierarchy(entity, updateContext, true);
98 }
99 roots_.clear();
100
101 for (auto [entity, hc, active] : updateContext.view<
102 helios::engine::ecs::components::HierarchyComponent,
103 helios::engine::mechanics::lifecycle::components::Inactive
104 >().whereEnabled()) {
105 if (hc->parent() || !hc->isDirty()) {
106 continue;
107 }
108 roots_.push_back(entity);
109 }
110
111 for (auto& entity : roots_) {
112 updateEntityHierarchy(entity, updateContext, false);
113 }
114 roots_.clear();
115 }
116 };
117}
118
119

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