Properly link flecs library

engine/libs/flecs/examples/cpp/entities/basics/.gitignore

@@ -0,0 +1,5 @@
+.bake_cache
+.DS_Store
+.vscode
+gcov
+bin

engine/libs/flecs/examples/cpp/entities/basics/include/basics.h

@@ -0,0 +1,16 @@
+#ifndef BASICS_H
+#define BASICS_H
+
+/* This generated file contains includes for project dependencies */
+#include "basics/bake_config.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+

engine/libs/flecs/examples/cpp/entities/basics/include/basics/bake_config.h

@@ -0,0 +1,24 @@
+/*
+                                   )
+                                  (.)
+                                  .|.
+                                  | |
+                              _.--| |--._
+                           .-';  ;`-'& ; `&.
+                          \   &  ;    &   &_/
+                           |"""---...---"""|
+                           \ | | | | | | | /
+                            `---.|.|.|.---'
+
+ * This file is generated by bake.lang.c for your convenience. Headers of
+ * dependencies will automatically show up in this file. Include bake_config.h
+ * in your main project file. Do not edit! */
+
+#ifndef BASICS_BAKE_CONFIG_H
+#define BASICS_BAKE_CONFIG_H
+
+/* Headers of public dependencies */
+#include <flecs.h>
+
+#endif
+

engine/libs/flecs/examples/cpp/entities/basics/project.json

@@ -0,0 +1,12 @@
+{
+    "id": "basics",
+    "type": "application",
+    "value": {
+        "author": "Jane Doe",
+        "description": "A simple hello world flecs application",
+        "use": [
+            "flecs"
+        ],
+        "language": "c++"
+    }
+}

engine/libs/flecs/examples/cpp/entities/basics/src/main.cpp

@@ -0,0 +1,53 @@
+#include <basics.h>
+#include <iostream>
+
+struct Position {
+    double x, y;
+};
+
+struct Walking { };
+
+int main(int, char *[]) {
+    flecs::world ecs;
+
+    // Create an entity with name Bob
+    flecs::entity bob = ecs.entity("Bob")
+        // The set operation finds or creates a component, and sets it.
+        // Components are automatically registered with the world.
+        .set<Position>({10, 20}) 
+        // The add operation adds a component without setting a value. This is
+        // useful for tags, or when adding a component with its default value.
+        .add<Walking>();
+
+    // Get the value for the Position component
+    const Position* ptr = bob.get<Position>();
+    std::cout << "{" << ptr->x << ", " << ptr->y << "}" << "\n";
+
+    // Overwrite the value of the Position component
+    bob.set<Position>({20, 30});
+
+    // Create another named entity
+    flecs::entity alice = ecs.entity("Alice")
+        .set<Position>({10, 20});
+
+    // Add a tag after entity is created
+    alice.add<Walking>();
+
+    // Print all of the components the entity has. This will output:
+    //    Position, Walking, (Identifier,Name)
+    std::cout << "[" << alice.type().str() << "]" << "\n";
+
+    // Remove tag
+    alice.remove<Walking>();
+
+    // Iterate all entities with Position
+    ecs.each([](flecs::entity e, Position& p) {
+        std::cout << e.name() << ": {" << p.x << ", " << p.y << "}" << "\n";
+    });
+
+    // Output
+    //  {10, 20}
+    //  [Position, Walking, (Identifier,Name)]
+    //  Alice: {10, 20}
+    //  Bob: {20, 30}
+}

engine/libs/flecs/examples/cpp/entities/emplace/include/emplace.h

@@ -0,0 +1,16 @@
+#ifndef EMPLACE_H
+#define EMPLACE_H
+
+/* This generated file contains includes for project dependencies */
+#include "emplace/bake_config.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+

engine/libs/flecs/examples/cpp/entities/emplace/include/emplace/bake_config.h

@@ -0,0 +1,24 @@
+/*
+                                   )
+                                  (.)
+                                  .|.
+                                  | |
+                              _.--| |--._
+                           .-';  ;`-'& ; `&.
+                          \   &  ;    &   &_/
+                           |"""---...---"""|
+                           \ | | | | | | | /
+                            `---.|.|.|.---'
+
+ * This file is generated by bake.lang.c for your convenience. Headers of
+ * dependencies will automatically show up in this file. Include bake_config.h
+ * in your main project file. Do not edit! */
+
+#ifndef EMPLACE_BAKE_CONFIG_H
+#define EMPLACE_BAKE_CONFIG_H
+
+/* Headers of public dependencies */
+#include <flecs.h>
+
+#endif
+

engine/libs/flecs/examples/cpp/entities/emplace/project.json

@@ -0,0 +1,11 @@
+{
+    "id": "emplace",
+    "type": "application",
+    "value": {
+        "use": [
+            "flecs"
+        ],
+        "public": false,
+        "language": "c++"
+    }
+}

engine/libs/flecs/examples/cpp/entities/emplace/src/main.cpp

@@ -0,0 +1,28 @@
+#include <emplace.h>
+#include <iostream>
+
+// The emplace method constructs a component directly in the storage vs. a 
+// regular set, which moves the value into an already constructed value in the
+// storage. This reduces the overhead of creating a new component.
+//
+// Components that do not have a default constructor need to be created with
+// emplace, as they can't be constructed automatically by flecs.
+
+struct NoDefaultCtor {
+    NoDefaultCtor(double x_, double y_) : x(x_), y(y_) { }
+
+    double x, y;
+};
+
+int main(int, char *[]) {
+    flecs::world ecs;
+
+    flecs::entity e = ecs.entity()
+        .emplace<NoDefaultCtor>(10.0, 20.0);
+
+    const NoDefaultCtor *ptr = e.get<NoDefaultCtor>();
+    std::cout << "{" << ptr->x << ", " << ptr->y << "}" << "\n";
+
+    // Output
+    //  {10, 20}
+}

engine/libs/flecs/examples/cpp/entities/hierarchy/.gitignore

@@ -0,0 +1,5 @@
+.bake_cache
+.DS_Store
+.vscode
+gcov
+bin

engine/libs/flecs/examples/cpp/entities/hierarchy/include/hierarchy.h

@@ -0,0 +1,16 @@
+#ifndef HIERARCHY_H
+#define HIERARCHY_H
+
+/* This generated file contains includes for project dependencies */
+#include "hierarchy/bake_config.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+

engine/libs/flecs/examples/cpp/entities/hierarchy/include/hierarchy/bake_config.h

@@ -0,0 +1,24 @@
+/*
+                                   )
+                                  (.)
+                                  .|.
+                                  | |
+                              _.--| |--._
+                           .-';  ;`-'& ; `&.
+                          \   &  ;    &   &_/
+                           |"""---...---"""|
+                           \ | | | | | | | /
+                            `---.|.|.|.---'
+
+ * This file is generated by bake.lang.c for your convenience. Headers of
+ * dependencies will automatically show up in this file. Include bake_config.h
+ * in your main project file. Do not edit! */
+
+#ifndef HIERARCHY_BAKE_CONFIG_H
+#define HIERARCHY_BAKE_CONFIG_H
+
+/* Headers of public dependencies */
+#include <flecs.h>
+
+#endif
+

engine/libs/flecs/examples/cpp/entities/hierarchy/project.json

@@ -0,0 +1,12 @@
+{
+    "id": "hierarchy",
+    "type": "application",
+    "value": {
+        "author": "Jane Doe",
+        "description": "A simple hello world flecs application",
+        "use": [
+            "flecs"
+        ],
+        "language": "c++"
+    }
+}

engine/libs/flecs/examples/cpp/entities/hierarchy/src/main.cpp

@@ -0,0 +1,65 @@
+#include <hierarchy.h>
+#include <iostream>
+
+struct Position {
+    double x, y;
+};
+
+struct Star { };
+struct Planet { };
+struct Moon { };
+
+void iterate_tree(flecs::entity e, Position p_parent = {0, 0}) {
+    // Print hierarchical name of entity & the entity type
+    std::cout << e.path() << " [" << e.type().str() << "]\n";
+
+    // Get entity position
+    const Position *p = e.get<Position>();
+
+    // Calculate actual position
+    Position p_actual = {p->x + p_parent.x, p->y + p_parent.y};
+    std::cout << "{" << p_actual.x << ", " << p_actual.y << "}\n\n";
+
+    // Iterate children recursively
+    e.children([&](flecs::entity child) {
+        iterate_tree(child, p_actual);
+    });
+}
+
+int main(int, char *[]) {
+    flecs::world ecs;
+
+    // Create a simple hierarchy.
+    // Hierarchies use ECS relationships and the builtin flecs::ChildOf relationship to
+    // create entities as children of other entities.
+
+    flecs::entity sun = ecs.entity("Sun")
+        .add<Star>()
+        .set<Position>({1, 1});
+
+        ecs.entity("Mercury")
+            .child_of(sun) // Shortcut for add(flecs::ChildOf, sun)
+            .add<Planet>()
+            .set<Position>({1, 1});
+
+        ecs.entity("Venus")
+            .child_of(sun)
+            .add<Planet>()
+            .set<Position>({2, 2});
+
+        flecs::entity earth = ecs.entity("Earth")
+            .child_of(sun)
+            .add<Planet>()
+            .set<Position>({3, 3});
+
+            flecs::entity moon = ecs.entity("Moon")
+                .child_of(earth)
+                .add<Moon>()
+                .set<Position>({0.1, 0.1});
+
+    // Is the Moon a child of Earth?
+    std::cout << "Child of Earth? " << moon.has(flecs::ChildOf, earth) << "\n\n";
+
+    // Do a depth-first walk of the tree
+    iterate_tree(sun);
+}

engine/libs/flecs/examples/cpp/entities/hooks/.gitignore

@@ -0,0 +1,5 @@
+.bake_cache
+.DS_Store
+.vscode
+gcov
+bin

engine/libs/flecs/examples/cpp/entities/hooks/include/hooks.h

@@ -0,0 +1,16 @@
+#ifndef HOOKS_H
+#define HOOKS_H
+
+/* This generated file contains includes for project dependencies */
+#include "hooks/bake_config.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+

engine/libs/flecs/examples/cpp/entities/hooks/include/hooks/bake_config.h

@@ -0,0 +1,24 @@
+/*
+                                   )
+                                  (.)
+                                  .|.
+                                  | |
+                              _.--| |--._
+                           .-';  ;`-'& ; `&.
+                          \   &  ;    &   &_/
+                           |"""---...---"""|
+                           \ | | | | | | | /
+                            `---.|.|.|.---'
+
+ * This file is generated by bake.lang.c for your convenience. Headers of
+ * dependencies will automatically show up in this file. Include bake_config.h
+ * in your main project file. Do not edit! */
+
+#ifndef HOOKS_BAKE_CONFIG_H
+#define HOOKS_BAKE_CONFIG_H
+
+/* Headers of public dependencies */
+#include <flecs.h>
+
+#endif
+

engine/libs/flecs/examples/cpp/entities/hooks/project.json

@@ -0,0 +1,10 @@
+{
+    "id": "hooks",
+    "type": "application",
+    "value": {
+        "use": [
+            "flecs"
+        ],
+        "language": "c++"
+    }
+}

engine/libs/flecs/examples/cpp/entities/hooks/src/main.cpp

@@ -0,0 +1,108 @@
+#include <hooks.h>
+#include <iostream>
+
+// Component hooks are callbacks that can be registered for a type that are
+// invoked during different parts of the component lifecycle.
+//
+// In the C++ API the ctor, dtor, copy and move methods of a type are 
+// automatically registered as component hooks.
+
+struct String {
+    String(const char *v = nullptr) {
+        flecs::log::trace("Ctor(const char*)");
+        value = ecs_os_strdup(v);
+    }
+
+    ~String() {
+        flecs::log::trace("Dtor");
+        ecs_os_free(value);
+    }
+
+    String(const String& obj) {
+        flecs::log::trace("Copy");
+        value = ecs_os_strdup(obj.value);
+    }
+
+    String(String&& obj) {
+        flecs::log::trace("Move");
+        value = obj.value;
+        obj.value = nullptr;
+    }
+
+    String& operator=(const String& obj) {
+        flecs::log::trace("Copy assign");
+        ecs_os_free(value);
+        value = ecs_os_strdup(obj.value);
+        return *this;
+    }
+
+    String& operator=(String&& obj) {
+        flecs::log::trace("Move assign");
+        ecs_os_free(value);
+        value = obj.value;
+        obj.value = nullptr;
+        return *this;
+    }
+
+    char *value;
+};
+
+struct Tag { };
+
+int main(int, char *[]) {
+    flecs::world ecs;
+
+    // Register additional add, remove and set hooks for type
+    ecs.component<String>()
+        .on_add([](flecs::entity e, String&) {
+            flecs::log::trace("OnAdd: %s", e.name().c_str());
+        })
+        .on_remove([](flecs::entity e, String&) {
+            flecs::log::trace("OnRemove: %s", e.name().c_str());
+        })
+        .on_set([](flecs::entity e, String&) {
+            flecs::log::trace("OnSet: %s", e.name().c_str());
+        });
+
+    // Register in advance to keep output trace clean
+    ecs.component<Tag>();
+
+    flecs::log::set_level(0);
+
+    flecs::entity e = ecs.entity("Entity");
+
+    flecs::log::push("e.add<String>()");
+    e.add<String>();
+    flecs::log::pop();
+
+    flecs::log::push("e.set<String>({\"Hello World\"})");
+    e.set<String>({"Hello World"});
+    flecs::log::pop();
+
+    // This operation changes the entity's archetype, which invokes a move
+    flecs::log::push("e.add<Tag>()");
+    e.add<Tag>();
+    flecs::log::pop();
+
+    flecs::log::push("e.destruct()");
+    e.destruct();
+    flecs::log::pop();
+
+    flecs::log::set_level(-1);
+
+    // Output:
+    //  info: e.add<String>()
+    //  info: | Ctor
+    //  info: | OnAdd: Entity
+    //  info: e.set<String>({"Hello World"})
+    //  info: | Ctor
+    //  info: | Move assign
+    //  info: | OnSet: Entity
+    //  info: | Dtor
+    //  info: e.add<Tag>()
+    //  info: | Move
+    //  info: | Dtor
+    //  info: e.destruct()
+    //  info: | OnRemove: Entity
+    //  info: | Dtor
+}

engine/libs/flecs/examples/cpp/entities/iterate_components/include/iterate_components.h

@@ -0,0 +1,16 @@
+#ifndef ITERATE_COMPONENTS_H
+#define ITERATE_COMPONENTS_H
+
+/* This generated file contains includes for project dependencies */
+#include "iterate_components/bake_config.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+

engine/libs/flecs/examples/cpp/entities/iterate_components/include/iterate_components/bake_config.h

@@ -0,0 +1,24 @@
+/*
+                                   )
+                                  (.)
+                                  .|.
+                                  | |
+                              _.--| |--._
+                           .-';  ;`-'& ; `&.
+                          \   &  ;    &   &_/
+                           |"""---...---"""|
+                           \ | | | | | | | /
+                            `---.|.|.|.---'
+
+ * This file is generated by bake.lang.c for your convenience. Headers of
+ * dependencies will automatically show up in this file. Include bake_config.h
+ * in your main project file. Do not edit! */
+
+#ifndef ITERATE_COMPONENTS_BAKE_CONFIG_H
+#define ITERATE_COMPONENTS_BAKE_CONFIG_H
+
+/* Headers of public dependencies */
+#include <flecs.h>
+
+#endif
+

engine/libs/flecs/examples/cpp/entities/iterate_components/project.json

@@ -0,0 +1,13 @@
+{
+    "id": "iterate_components",
+    "type": "application",
+    "value": {
+        "author": "Jane Doe",
+        "description": "A simple hello world flecs application",
+        "use": [
+            "flecs"
+        ],
+        "language": "c++",
+        "public": false
+    }
+}

engine/libs/flecs/examples/cpp/entities/iterate_components/src/main.cpp

@@ -0,0 +1,99 @@
+#include <iterate_components.h>
+#include <iostream>
+
+// Ordinary components
+struct Position {
+    double x, y;
+};
+
+struct Velocity {
+    double x, y;
+};
+
+// Tag
+struct Human { };
+
+// Two tags used to create a pair
+struct Eats { };
+struct Apples { };
+
+void iterate_components(flecs::entity e) {
+    // 1. The easiest way to print the components is to use type::str
+    std::cout << e.type().str() << "\n\n";
+
+    // 2. To get individual component ids, use entity::each
+    int32_t i = 0;
+    e.each([&](flecs::id id) {
+        std::cout << i++ << ": " << id.str() << "\n";
+    });
+    std::cout << "\n";
+
+    // 3. we can also inspect and print the ids in our own way. This is a
+    // bit more complicated as we need to handle the edge cases of what can be
+    // encoded in an id, but provides the most flexibility.
+    i = 0;
+    e.each([&](flecs::id id) {
+        std::cout << i++ << ": ";
+
+        if (id.is_pair()) {
+            // If id is a pair, extract & print both parts of the pair
+            flecs::entity rel = id.first();
+            flecs::entity tgt = id.second();
+            std::cout << "rel: " << rel.name() << ", " << "tgt: " << tgt.name();
+        } else {
+            // Id contains a regular entity. Strip role before printing.
+            flecs::entity comp = id.entity();
+            std::cout << "entity: " << comp.name();
+        }
+
+        std::cout << "\n";
+    });
+
+    std::cout << "\n\n";
+}
+
+int main(int, char *[]) {
+    flecs::world ecs;
+
+    flecs::entity bob = ecs.entity()
+        .set<Position>({10, 20})
+        .set<Velocity>({1, 1})
+        .add<Human>()
+        .add<Eats, Apples>();
+
+    std::cout << "Bob's components:\n";
+    iterate_components(bob);
+
+    // We can use the same function to iterate the components of a component
+    std::cout << "Position's components:\n";
+    iterate_components(ecs.component<Position>());
+}
+
+// Output:
+
+// Bob's components:
+// Position, Velocity, Human, (Eats,Apples)
+// 
+// 0: Position
+// 1: Velocity
+// 2: Human
+// 3: (Eats,Apples)
+// 
+// 0: entity: Position
+// 1: entity: Velocity
+// 2: entity: Human
+// 3: rel: Eats, tgt: Apples
+// 
+// 
+// Position's components:
+// Component, (Identifier,Name), (Identifier,Symbol), (OnDelete,Panic)
+// 
+// 0: Component
+// 1: (Identifier,Name)
+// 2: (Identifier,Symbol)
+// 3: (OnDelete,Panic)
+// 
+// 0: entity: Component
+// 1: rel: Identifier, tgt: Name
+// 2: rel: Identifier, tgt: Symbol
+// 3: rel: OnDelete, tgt: Panic

engine/libs/flecs/examples/cpp/entities/multi_set_get/include/multi_set_get.h

@@ -0,0 +1,16 @@
+#ifndef MULTI_SET_GET_H
+#define MULTI_SET_GET_H
+
+/* This generated file contains includes for project dependencies */
+#include "multi_set_get/bake_config.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+

engine/libs/flecs/examples/cpp/entities/multi_set_get/include/multi_set_get/bake_config.h

@@ -0,0 +1,24 @@
+/*
+                                   )
+                                  (.)
+                                  .|.
+                                  | |
+                              _.--| |--._
+                           .-';  ;`-'& ; `&.
+                          \   &  ;    &   &_/
+                           |"""---...---"""|
+                           \ | | | | | | | /
+                            `---.|.|.|.---'
+
+ * This file is generated by bake.lang.c for your convenience. Headers of
+ * dependencies will automatically show up in this file. Include bake_config.h
+ * in your main project file. Do not edit! */
+
+#ifndef MULTI_SET_GET_BAKE_CONFIG_H
+#define MULTI_SET_GET_BAKE_CONFIG_H
+
+/* Headers of public dependencies */
+#include <flecs.h>
+
+#endif
+

engine/libs/flecs/examples/cpp/entities/multi_set_get/project.json

@@ -0,0 +1,11 @@
+{
+    "id": "multi_set_get",
+    "type": "application",
+    "value": {
+        "use": [
+            "flecs"
+        ],
+        "public": false,
+        "language": "c++"
+    }
+}

engine/libs/flecs/examples/cpp/entities/multi_set_get/src/main.cpp

@@ -0,0 +1,39 @@
+#include <multi_set_get.h>
+#include <iostream>
+
+/* This code shows how to get & set multiple components in a single command */
+
+struct Position {
+    double x, y;
+};
+
+struct Mass {
+    double value;
+};
+
+int main(int, char *[]) {
+    flecs::world ecs;
+
+    // Create new entity, set Position and Mass component
+    flecs::entity e = ecs.entity()
+        .set([](Position& p, Mass& m) {
+            p.x = 10;
+            p.y = 20;
+            m.value = 100;
+        });
+
+    // Print values of Position and Mass component
+    bool found = e.get([](const Position& p, const Mass& m) {
+        std::cout << "Position: {" << p.x << ", " << p.y << "}\n"
+                  << "Mass: {" << m.value << "}\n";
+    });
+
+    std::cout << "Components found: " << (found ? "true" : "false") << "\n";
+
+    // Output:
+    //  Position: {10, 20}
+    //  Mass: {100}
+    //  Components found: true
+    
+    return 0;
+}

engine/libs/flecs/examples/cpp/entities/prefab/.gitignore

@@ -0,0 +1,5 @@
+.bake_cache
+.DS_Store
+.vscode
+gcov
+bin

engine/libs/flecs/examples/cpp/entities/prefab/include/prefab.h

@@ -0,0 +1,16 @@
+#ifndef PREFAB_H
+#define PREFAB_H
+
+/* This generated file contains includes for project dependencies */
+#include "prefab/bake_config.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+

engine/libs/flecs/examples/cpp/entities/prefab/include/prefab/bake_config.h

@@ -0,0 +1,24 @@
+/*
+                                   )
+                                  (.)
+                                  .|.
+                                  | |
+                              _.--| |--._
+                           .-';  ;`-'& ; `&.
+                          \   &  ;    &   &_/
+                           |"""---...---"""|
+                           \ | | | | | | | /
+                            `---.|.|.|.---'
+
+ * This file is generated by bake.lang.c for your convenience. Headers of
+ * dependencies will automatically show up in this file. Include bake_config.h
+ * in your main project file. Do not edit! */
+
+#ifndef PREFAB_BAKE_CONFIG_H
+#define PREFAB_BAKE_CONFIG_H
+
+/* Headers of public dependencies */
+#include <flecs.h>
+
+#endif
+

engine/libs/flecs/examples/cpp/entities/prefab/project.json

@@ -0,0 +1,12 @@
+{
+    "id": "prefab",
+    "type": "application",
+    "value": {
+        "author": "Jane Doe",
+        "description": "A simple hello world flecs application",
+        "use": [
+            "flecs"
+        ],
+        "language": "c++"
+    }
+}

engine/libs/flecs/examples/cpp/entities/prefab/src/main.cpp

@@ -0,0 +1,70 @@
+#include <prefab.h>
+#include <iostream>
+
+// Prefabs are entities that can be used as templates for other entities. They
+// are created with a builtin Prefab tag, which by default excludes them from
+// queries and systems.
+
+struct Attack { double value; };
+struct Defense { double value; };
+struct FreightCapacity { double value; };
+struct ImpulseSpeed { double value; };
+struct HasFTL { };
+
+struct Position { double x = 0; double y = 0; };
+
+int main(int, char *[]) {
+    flecs::world ecs;
+
+    // Create a prefab hierarchy.
+    flecs::entity spaceship = ecs.prefab("Spaceship")
+        // Add components to prefab entity as usual
+        .set<ImpulseSpeed>({50})
+        .set<Defense>({50})
+
+        // By default components in an inheritance hierarchy are shared between
+        // entities. The override function ensures that instances have a private
+        // copy of the component.
+        .override<Position>();
+
+        flecs::entity freighter = ecs.prefab("Freighter")
+            // Short for .add(flecs::IsA, spaceship). This ensures the entity
+            // inherits all components from spaceship.
+            .is_a(spaceship)
+            .add<HasFTL>()
+            .set<FreightCapacity>({100})
+            .set<Defense>({100});
+
+            flecs::entity mammoth_freighter = ecs.prefab("MammothFreighter")
+                .is_a(freighter)
+                .set<FreightCapacity>({500})
+                .set<Defense>({300});
+
+        ecs.prefab("Frigate")
+            .is_a(spaceship)
+            .add<HasFTL>()
+            .set<Attack>({100})
+            .set<Defense>({75})
+            .set<ImpulseSpeed>({125});
+
+    // Create a regular entity from a prefab.
+    // The instance will have a private copy of the Position component, because
+    // of the override in the spaceship entity. All other components are shared.
+    flecs::entity inst = ecs.entity("my_mammoth_freighter")
+        .is_a(mammoth_freighter);
+
+    // Inspect the type of the entity. This outputs:
+    //    Position,(Identifier,Name),(IsA,MammothFreighter)
+    std::cout << "Instance type: [" << inst.type().str() << "]\n";
+
+    // Even though the instance doesn't have a private copy of ImpulseSpeed, we
+    // can still get it using the regular API (outputs 50)
+    const ImpulseSpeed *ptr = inst.get<ImpulseSpeed>();
+    std::cout << "Impulse speed: " << ptr->value << "\n";
+
+    // Prefab components can be iterated just like regular components:
+    ecs.each([](flecs::entity e, ImpulseSpeed& is, Position& p) {
+        p.x += is.value;
+        std::cout << e.name() << ": {" << p.x << ", " << p.y << "}\n"; 
+    });
+}