Properly link flecs library

engine/libs/flecs/examples/cpp/observers/entity_event/include/entity_event.h

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

engine/libs/flecs/examples/cpp/observers/entity_event/include/entity_event/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 ENTITY_EVENT_BAKE_CONFIG_H
+#define ENTITY_EVENT_BAKE_CONFIG_H
+
+/* Headers of public dependencies */
+#include <flecs.h>
+
+#endif
+

engine/libs/flecs/examples/cpp/observers/entity_event/project.json

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

engine/libs/flecs/examples/cpp/observers/entity_event/src/main.cpp

@@ -0,0 +1,55 @@
+#include <iostream>
+#include <entity_event.h>
+
+// Entity events are events that are emitted and observed for a specific entity.
+// They are a thin wrapper around regular observers, which match against queries
+// instead of single entities. While they work similarly under the hood, entity
+// events provide a much simpler API.
+//
+// An entity event only needs two pieces of data:
+// - The entity on which to emit the event
+// - The event to emit
+
+// An event without payload
+struct Click { };
+
+// An event with payload
+struct Resize {
+    double width, height;
+};
+
+int main(int, char *[]) {
+    flecs::world ecs;
+
+    // Create a widget entity
+    flecs::entity widget = ecs.entity("MyWidget");
+
+    // Observe the Click event on the widget entity.
+    widget.observe<Click>([]() {
+        std::cout << "clicked!\n";
+    });
+
+    // Observers can have an entity argument that holds the event source.
+    // This allows the same function to be reused for different entities.
+    widget.observe<Click>([](flecs::entity src) {
+        std::cout << "clicked on " << src.path() << "!\n";
+    });
+
+    // Observe the Resize event. Events with payload are passed as arguments
+    // to the observer callback.
+    widget.observe([](Resize& p) {
+        std::cout << "resized to {" 
+                  << p.width << ", " << p.height << "}!\n"; 
+    });
+
+    // Emit the Click event
+    widget.emit<Click>();
+
+    // Emit the Resize event
+    widget.emit<Resize>({100, 200});
+
+    // Output
+    //   clicked!
+    //   clicked on ::MyWidget!
+    //   resized to {100, 200}!
+}