Add interactions.

src/dusk/overworld/entity/entity.c

@@ -109,7 +109,27 @@ void entityMove(entity_t *ent, const facingdir_t dir) {
   }
 }
 
-bool entityIsMoving(const entity_t *ent) {
+bool_t entityIsMoving(const entity_t *ent) {
   assertNotNull(ent, "Entity cannot be NULL");
   return ent->subX != 0 || ent->subY != 0;
+}
+
+bool_t entityInteract(const entity_t *ent) {
+  assertNotNull(ent, "Entity cannot be NULL.");
+  assertTrue(ent->type == ENTITY_TYPE_PLAYER, "Entity should be player.");
+  if(entityIsMoving(ent)) return false;
+
+  uint8_t targetX = ent->x, targetY = ent->y;
+  facingDirAdd(ent->direction, &targetX, &targetY);
+
+  entity_t *target = overworldEntityGetAtPosition(targetX, targetY);
+  assertFalse(target == ent, "Cannot interact with self.");
+
+  if(target == NULL) return false;
+  assertTrue(target->type < ENTITY_TYPE_COUNT, "Invalid entity type.");
+
+  if(ENTITY_CALLBACKS[target->type].interact == NULL) return false;
+  ENTITY_CALLBACKS[target->type].interact(target);
+  
+  return true;
 }

src/dusk/overworld/entity/entity.h

@@ -78,4 +78,12 @@ void entityMove(entity_t *entity, const facingdir_t dir);
  * @param entity The entity to check.
  * @return TRUE if the entity is moving, FALSE otherwise.
  */
-bool_t entityIsMoving(const entity_t *entity);
+bool_t entityIsMoving(const entity_t *entity);
+
+/**
+ * Make this entity attempt to interact with the world.
+ * 
+ * @param entity The entity that is doing the interaction.
+ * @return TRUE if an entity was interacted with, FALSE otherwise.
+ */
+bool_t entityInteract(const entity_t *entity);

src/dusk/overworld/entity/npc.c

@@ -14,4 +14,5 @@ void npcUpdate(entity_t *ent) {
 }
 
 void npcInteract(entity_t *ent) {
+  printf("Interact\n");
 }

src/dusk/overworld/entity/player.c

@@ -27,6 +27,7 @@ void playerUpdate(entity_t *ent) {
   } else if(inputIsDown(INPUT_DOWN)) {
     entityMove(ent, FACING_DIRECTION_SOUTH);
   } else if(inputWasPressed(INPUT_ACCEPT)) {
+    entityInteract(ent);
   }
 
 }