Add inventory.

archive/rpg/entity/entitydir.h

@@ -0,0 +1,50 @@
+/**
+ * Copyright (c) 2025 Dominic Masters
+ * 
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#pragma once
+#include "rpg/overworld/worldpos.h"
+
+typedef enum {
+  ENTITY_DIR_UP = ENTITY_DIR_NORTH,
+  ENTITY_DIR_DOWN = ENTITY_DIR_SOUTH,
+  ENTITY_DIR_LEFT = ENTITY_DIR_WEST,
+  ENTITY_DIR_RIGHT = ENTITY_DIR_EAST,
+} entitydir_t;
+
+/**
+ * Gets the opposite direction of a given direction.
+ * 
+ * @param dir The direction to get the opposite of.
+ * @return entitydir_t The opposite direction.
+ */
+entitydir_t entityDirGetOpposite(const entitydir_t dir);
+
+/**
+ * Asserts a given direction is valid.
+ * 
+ * @param dir The direction to validate.
+ * @param msg The message to display if the assertion fails.
+ */
+#define assertValidEntityDir(dir, msg) \
+  assertTrue( \
+    (dir) == ENTITY_DIR_NORTH || \
+    (dir) == ENTITY_DIR_EAST || \
+    (dir) == ENTITY_DIR_SOUTH || \
+    (dir) == ENTITY_DIR_WEST, \
+    msg \
+  )
+
+/**
+ * Gets the relative x and y offsets for a given direction.
+ * 
+ * @param dir The direction to get offsets for.
+ * @param relX Pointer to store the relative x offset.
+ * @param relY Pointer to store the relative y offset.
+ */
+void entityDirGetRelative(
+  const entitydir_t dir, worldunits_t *relX, worldunits_t *relY
+);