#55 add example demonstrating optional columns

SanderMertens · Oct 6, 2019 · e2a5737 · e2a5737
1 parent 4d129f6
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diff --git a/examples/22_optional/.gitignore b/examples/22_optional/.gitignore
@@ -0,0 +1,5 @@
+.bake_cache
+.DS_Store
+.vscode
+gcov
+bin
diff --git a/examples/22_optional/include/optional.h b/examples/22_optional/include/optional.h
@@ -0,0 +1,16 @@
+#ifndef OPTIONAL_H
+#define OPTIONAL_H
+
+/* This generated file contains includes for project dependencies */
+#include "optional/bake_config.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
diff --git a/examples/22_optional/include/optional/bake_config.h b/examples/22_optional/include/optional/bake_config.h
@@ -0,0 +1,44 @@
+/*
+                                   )
+                                  (.)
+                                  .|.
+                                  | |
+                              _.--| |--._
+                           .-';  ;`-'& ; `&.
+                          \   &  ;    &   &_/
+                           |"""---...---"""|
+                           \ | | | | | | | /
+                            `---.|.|.|.---'
+
+ * 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 OPTIONAL_BAKE_CONFIG_H
+#define OPTIONAL_BAKE_CONFIG_H
+
+/* Headers of public dependencies */
+#include <flecs.h>
+
+/* Headers of private dependencies */
+#ifdef OPTIONAL_IMPL
+/* No dependencies */
+#endif
+
+/* Convenience macro for exporting symbols */
+#ifndef OPTIONAL_STATIC
+  #if OPTIONAL_IMPL && (defined(_MSC_VER) || defined(__MINGW32__))
+    #define OPTIONAL_EXPORT __declspec(dllexport)
+  #elif OPTIONAL_IMPL
+    #define OPTIONAL_EXPORT __attribute__((__visibility__("default")))
+  #elif defined _MSC_VER
+    #define OPTIONAL_EXPORT __declspec(dllimport)
+  #else
+    #define OPTIONAL_EXPORT
+  #endif
+#else
+  #define OPTIONAL_EXPORT
+#endif
+
+#endif
+
diff --git a/examples/22_optional/project.json b/examples/22_optional/project.json
@@ -0,0 +1,12 @@
+{
+    "id": "optional",
+    "type": "application",
+    "value": {
+        "author": "Jane Doe",
+        "description": "A simple hello world flecs application",
+        "public": false,
+        "use": [
+            "flecs"
+        ]
+    }
+}
diff --git a/examples/22_optional/src/main.c b/examples/22_optional/src/main.c
@@ -0,0 +1,51 @@
+#include <optional.h>
+
+typedef float Health;
+typedef float Stamina;
+typedef float Mana;
+
+void Regenerate(ecs_rows_t *rows) {
+    ECS_COLUMN(rows, Health, health, 1);
+    ECS_COLUMN(rows, Stamina, stamina, 2);
+    ECS_COLUMN(rows, Mana, mana, 3);
+
+    for (int i = 0; i < rows->count; i ++) {
+        if (health) {
+            health[i] ++;
+            printf("%d: process health\n", (int)rows->entities[i]);
+        }
+
+        if (stamina) {
+            stamina[i] ++;
+            printf("%d: process stamina\n", (int)rows->entities[i]);
+        }
+
+        if (mana) {
+            mana[i] ++;
+            printf("%d: process mana\n", (int)rows->entities[i]);
+        }
+    }
+}
+
+int main(int argc, char *argv[]) {
+    /* Create the world, pass arguments for overriding the number of threads,fps
+     * or for starting the admin dashboard (see flecs.h for details). */
+    ecs_world_t *world = ecs_init_w_args(argc, argv);
+
+    ECS_COMPONENT(world, Health);
+    ECS_COMPONENT(world, Stamina);
+    ECS_COMPONENT(world, Mana);
+
+    ECS_SYSTEM(world, Regenerate, EcsOnUpdate, ?Health, ?Stamina, ?Mana);
+
+    /* Create three entities that will all match with the Regenerate system */
+    ecs_new(world, Health);
+    ecs_new(world, Stamina);
+    ecs_new(world, Mana);
+
+    /* Run systems */
+    ecs_progress(world, 0);
+
+    /* Cleanup */
+    return ecs_fini(world);
+}