interactions

src/dusk/entity/entity.c

@@ -16,8 +16,15 @@ entity_t ENTITIES[ENTITY_COUNT_MAX] = {0};
 
 entitycallback_t ENTITY_CALLBACKS[ENTITY_TYPE_COUNT] = {
   {NULL}, // ENTITY_TYPE_NULL
-  {playerNPCInit, playerNPCUpdate}, // ENTITY_TYPE_PLAYER
-  {npcInit, npcUpdate} // ENTITY_TYPE_NPC
+  {
+    .init = playerNPCInit,
+    .update = playerNPCUpdate,
+  },
+  {
+    .init = npcInit,
+    .update = npcUpdate,
+    .interact = npcInteract,
+  },
 };
 
 void entityInit(entity_t *entity, const entitytype_t type) {

src/dusk/entity/entity.h

@@ -47,6 +47,7 @@ typedef struct _entity_t {
 typedef struct {
   void (*init) (entity_t *entity);
   void (*update) (entity_t *entity);
+  void (*interact)(entity_t *player, entity_t *self);
 } entitycallback_t;
 
 extern entity_t ENTITIES[ENTITY_COUNT_MAX];
@@ -66,3 +67,11 @@ void entityInit(entity_t *entity, const entitytype_t type);
  * @param entity Pointer to the entity to update.
  */
 void entityUpdate(entity_t *entity);
+
+/**
+ * Converts an entity direction to an angle in fixed248_t format.
+ * 
+ * @param dir The entity direction to convert.
+ * @return The angle corresponding to the entity direction.
+ */
+fixed248_t entityDirToAngle(const entitydir_t dir);

src/dusk/entity/npc.c

@@ -14,3 +14,7 @@ void npcInit(entity_t *entity) {
 void npcUpdate(entity_t *entity) {
   
 }
+
+void npcInteract(entity_t *player, entity_t *self) {
+  printf("I am being interacted with!\n");
+}

src/dusk/entity/npc.h

@@ -21,3 +21,11 @@ void npcInit(entity_t *entity);
  * @param entity The entity to update.
  */
 void npcUpdate(entity_t *entity);
+
+/**
+ * Handles interaction between the player and the NPC.
+ * 
+ * @param player The player entity interacting with the NPC.
+ * @param self The NPC entity being interacted with.
+ */
+void npcInteract(entity_t *player, entity_t *self);

src/dusk/entity/player.c

@@ -82,6 +82,7 @@ void playerNPCUpdate(entity_t *entity) {
   } else {
     entity->vx = 0;
     entity->vy = 0;
+  }
 
   // Interact
   if(inputPressed(INPUT_BIND_ACTION)) {
@@ -92,29 +93,53 @@ void playerNPCUpdate(entity_t *entity) {
         continue;
       }
 
+      // Is the other entity interactable?
+      if(ENTITY_CALLBACKS[other->type].interact == NULL) {
+        other++;
+        continue;
+      }
+
       fixed248_t distanceX = fx248Subfx248(other->x, entity->x);
       fixed248_t distanceY = fx248Subfx248(other->y, entity->y);
-        fixed248_t distance = fx248Sqrt(
-          fx248Addfx248(
+      fixed248_t distance = fx248Sqrt(fx248Addfx248(
         fx248Mulfx248(distanceX, distanceX),
         fx248Mulfx248(distanceY, distanceY)
-          )
-        );
-        
-        if(other->id == 102) {
-          printf("Distance to entity %u: %f\n", other->id, fx248Tof32(distance));
-        }
+      ));
 
       if(distance > PLAYER_INTERACT_RANGE) {
         other++;
         continue;
       }
 
+      // Get angle
+      fixed248_t angle = fx248Atan2(distanceY, distanceX);
+      while(angle < 0) angle += FX248_PI;
+      fixed248_t selfAngle = entityDirToAngle(entity->dir);
+      while(selfAngle < 0) selfAngle += FX248_PI;
       
-        printf("Interacting with entity %u\n", other->id);
+      // Check if angle is within range
+      fixed248_t angleDiff = fx248Subfx248(angle, selfAngle);
+      if(angleDiff > FX248_HALF_PI) angleDiff -= FX248_PI;
+      if(angleDiff < -FX248_HALF_PI) angleDiff += FX248_PI;
+      if(fx248Abs(angleDiff) > PLAYER_INTERACT_ANGLE) {
         other++;
+        continue;
+      }
 
+      ENTITY_CALLBACKS[other->type].interact(entity, other);
+      entity->vx = 0;
+      entity->vy = 0;
+      other++;
     } while(other != ENTITIES + ENTITY_COUNT_MAX);
   }
 }
+
+fixed248_t entityDirToAngle(const entitydir_t dir) {
+  switch(dir) {
+    case ENTITY_DIR_NORTH: return FX248_HALF_PI;
+    case ENTITY_DIR_SOUTH: return -FX248_HALF_PI;
+    case ENTITY_DIR_EAST: return 0;
+    case ENTITY_DIR_WEST: return FX248_PI;
+    default: return 0; // Should never happen
+  }
 }

src/dusk/entity/player.h

@@ -18,7 +18,10 @@ typedef struct {
 #define PLAYER_ENTITY_ID (UINT32_MAX-1)
 #define PLAYER_MOVE_SPEED FIXED248(1, 0)
 #define PLAYER_MOVE_SPEED_XY FIXED248(0, 80)
-#define PLAYER_INTERACT_RANGE FIXED248((TILE_WIDTH_HEIGHT + (TILE_WIDTH_HEIGHT / 3)), 0)
+#define PLAYER_INTERACT_RANGE FIXED248( \
+  (TILE_WIDTH_HEIGHT + (TILE_WIDTH_HEIGHT / 3)), 0 \
+)
+#define PLAYER_INTERACT_ANGLE ((fixed248_t)175)
 
 /**
  * Initializes the player and all player-related entities.

src/dusk/util/fixed.c

@@ -199,3 +199,59 @@ fixed248_t fx248Clamp(
 ) {
   return (a < min) ? min : (a > max) ? max : a;
 }
+
+fixed248_t fx248Abs(const fixed248_t a) {
+  return (a < 0) ? -a : a;
+}
+
+
+
+fixed248_t fx248Atan2(
+  const fixed248_t y,
+  const fixed248_t x
+) {
+  // Handle special cases
+  if (x == 0) {
+    if (y > 0) return FX248_HALF_PI;
+    if (y < 0) return -FX248_HALF_PI;
+    return 0;
+  }
+
+  // Use absolute values for quadrant correction
+  fixed248_t abs_y = y;
+  if (abs_y < 0) abs_y = -abs_y;
+
+  fixed248_t angle;
+  if (abs_y < fx248Abs(x)) {
+    fixed248_t z = fx248Divfx248(y, x);
+    fixed248_t z2 = fx248Mulfx248(z, z);
+    fixed248_t z3 = fx248Mulfx248(z2, z);
+    fixed248_t z5 = fx248Mulfx248(z3, z2);
+    angle = fx248Subfx248(
+      fx248Addfx248(z, fx248Divfx248(z5, fx248Fromi32(5))),
+      fx248Divfx248(z3, fx248Fromi32(3))
+    );
+    if (x < 0) {
+      if (y < 0) {
+        angle -= FX248_PI;
+      } else {
+        angle += FX248_PI;
+      }
+    }
+  } else {
+    fixed248_t z = fx248Divfx248(x, y);
+    fixed248_t z2 = fx248Mulfx248(z, z);
+    fixed248_t z3 = fx248Mulfx248(z2, z);
+    fixed248_t z5 = fx248Mulfx248(z3, z2);
+    angle = fx248Subfx248(
+      fx248Addfx248(z, fx248Divfx248(z5, fx248Fromi32(5))),
+      fx248Divfx248(z3, fx248Fromi32(3))
+    );
+    if (y > 0) {
+      angle = FX248_HALF_PI - angle;
+    } else {
+      angle = -FX248_HALF_PI - angle;
+    }
+  }
+  return angle;
+}

src/dusk/util/fixed.h

@@ -20,6 +20,10 @@ typedef int32_t fixed248_t;
 ))
 #define FIXED248_ONE (FIXED248(1, 0))
 #define FIXED248_ZERO (FIXED248(0, 0))
+#define FX248_PI 804
+#define FX248_HALF_PI 402
+#define FX248_3PI_4 603 
+#define FX248_NEG_PI -804
 
 /**
  * Convert an int32_t value to a fixed248_t value.
@@ -351,3 +355,25 @@ fixed248_t fx248Clamp(
   const fixed248_t min,
   const fixed248_t max
 );
+
+/**
+ * Returns the absolute value of a fixed248_t value.
+ * 
+ * @param a The fixed248_t value to calculate the absolute value of.
+ * @return The absolute value as a fixed248_t value.
+ */
+fixed248_t fx248Abs(const fixed248_t a);
+
+
+
+/**
+ * Calculate the arctangent of a fixed248_t value.
+ * 
+ * @param y Y coordinate value.
+ * @param x X coordinate value.
+ * @return The arctangent of the value as a fixed248_t value.
+ */
+fixed248_t fx248Atan2(
+  const fixed248_t y,
+  const fixed248_t x
+);