Properly link flecs library

engine/libs/flecs/examples/c/modules/simple_module/src/main.c

@@ -0,0 +1,38 @@
+#include <simple_module.h>
+#include <stdio.h>
+
+void PrintPosition(ecs_iter_t *it) {
+    Position *p = ecs_field(it, Position, 1);
+
+    for (int i = 0; i < it->count; i ++) {
+        printf("p = {%f, %f} (system)\n", p[i].x, p[i].y);
+    }
+}
+
+int main(int argc, char *argv[]) {
+    ecs_world_t *world = ecs_init_w_args(argc, argv);
+
+    // Import module which calls the SimpleModuleImport function
+    ECS_IMPORT(world, SimpleModule);
+
+    // Create system that uses component from module. Note how the component
+    // identifier is prefixed with the module.
+    ECS_SYSTEM(world, PrintPosition, EcsOnUpdate, simple.module.Position);
+
+    // Create entity with components imported from module
+    ecs_entity_t e = ecs_set(world, 0, Position, {10, 20});
+                     ecs_set(world, e, Velocity, {1, 2});
+
+    // Call progress which runs imported Move system
+    ecs_progress(world, 0);
+
+    // Use component from module in operation
+    const Position *p = ecs_get(world, e, Position);
+    printf("p = {%f, %f} (get)\n", p->x, p->y);
+
+    return ecs_fini(world);
+
+    // Output:
+    //   p = {11.000000, 22.000000} (system)
+    //   p = {11.000000, 22.000000} (get)
+}

engine/libs/flecs/examples/c/modules/simple_module/src/simple_module.c

@@ -0,0 +1,28 @@
+#include <simple_module.h>
+
+ECS_COMPONENT_DECLARE(Position);
+ECS_COMPONENT_DECLARE(Velocity);
+
+void Move(ecs_iter_t *it) {
+    Position *p = ecs_field(it, Position, 1);
+    Velocity *v = ecs_field(it, Velocity, 2);
+
+    for (int i = 0; i < it->count; i ++) {
+        p[i].x += v[i].x;
+        p[i].y += v[i].y;
+    }
+}
+
+void SimpleModuleImport(ecs_world_t *world) {
+    // Create the module entity. The PascalCase module name is translated to a
+    // lower case path for the entity name, like "simple.module".
+    ECS_MODULE(world, SimpleModule);
+
+    // All contents of the module are created inside the module's namespace, so
+    // the Position component will be created as simple.module.Position
+
+    ECS_COMPONENT_DEFINE(world, Position);
+    ECS_COMPONENT_DEFINE(world, Velocity);
+
+    ECS_SYSTEM(world, Move, EcsOnUpdate, Position, Velocity);
+}