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+/* $Id$ */
+
+#ifndef NEWGRF_CALLBACKS_H
+#define NEWGRF_CALLBACKS_H
+
+/** @file newgrf_callbacks.h
+ */
+
+/**
+ * List of implemented NewGRF callbacks.
+ * Names are formatted as CBID_<CLASS>_<CALLBACK>
+ */
+enum CallbackID {
+	// Powered wagons, if the result is lower as 0x40 then the wagon is powered
+	// TODO: interpret the rest of the result, aka "visual effects"
+	CBID_TRAIN_WAGON_POWER          = 0x10,
+
+	// Vehicle length, returns the amount of 1/8's the vehicle is shorter
+	// only for train vehicles
+	CBID_TRAIN_VEHICLE_LENGTH       = 0x11,
+
+	/* Called to determine the amount of cargo to load per unit of time when
+	 * using gradual loading. */
+	CBID_VEHICLE_LOAD_AMOUNT        = 0x12,
+
+	/* Called (if appropriate bit in callback mask is set) to determine if a
+	 * newstation should be made available to build */
+	CBID_STATION_AVAILABILITY       = 0x13,
+
+	/* Called (if appropriate bit in callback mask is set) when drawing a tile
+	 * to choose a sprite layout to draw, instead of the standard 0-7 range */
+	CBID_STATION_SPRITE_LAYOUT      = 0x14,
+
+	// Refit capacity, the passed vehicle needs to have its ->cargo_type set to
+	// the cargo we are refitting to, returns the new cargo capacity
+	CBID_VEHICLE_REFIT_CAPACITY     = 0x15,
+
+	CBID_TRAIN_ARTIC_ENGINE         = 0x16,
+
+	CBID_VEHICLE_CARGO_SUFFIX       = 0x19,
+
+	CBID_TRAIN_ALLOW_WAGON_ATTACH   = 0x1D,
+
+	/* This callback is called from vehicle purchase lists. It returns a value to be
+	 * used as a custom string ID in the 0xD000 range. */
+	CBID_VEHICLE_ADDITIONAL_TEXT    = 0x23,
+
+	/* Called when building a station to customize the tile layout */
+	CBID_STATION_TILE_LAYOUT        = 0x24,
+
+	/* Called when the player (or AI) tries to start or stop a vehicle. Mainly
+	 * used for preventing a vehicle from leaving the depot. */
+	CBID_VEHICLE_START_STOP_CHECK   = 0x31,
+
+	/* Called to play a special sound effect */
+	CBID_VEHICLE_SOUND_EFFECT       = 0x33,
+};
+
+/**
+ * Callback masks for vehicles, indicates which callbacks are used by a vehicle.
+ * Some callbacks are always used and don't have a mask.
+ */
+enum VehicleCallbackMask {
+	CBM_WAGON_POWER    = 0, ///< Powered wagons (trains only)
+	CBM_VEHICLE_LENGTH = 1, ///< Vehicle length (trains only)
+	CBM_LOAD_AMOUNT    = 2, ///< Load amount
+	CBM_REFIT_CAPACITY = 3, ///< Cargo capacity after refit
+	CBM_ARTIC_ENGINE   = 4, ///< Add articulated engines (trains only)
+	CBM_CARGO_SUFFIX   = 5, ///< Show suffix after cargo name
+	CBM_COLOUR_REMAP   = 6, ///< Change colour mapping of vehicle
+	CBM_SOUND_EFFECT   = 7, ///< Vehicle uses custom sound effects
+};
+
+/**
+ * Callback masks for stations.
+ */
+enum StationCallbackMask {
+	CBM_STATION_AVAIL = 0, ///< Availability of station in construction window
+	CBM_CUSTOM_LAYOUT = 1, ///< Use callback to select a tile layout to use
+};
+
+/**
+ * Result of a failed callback.
+ */
+enum {
+	CALLBACK_FAILED = 0xFFFF
+};
+
+#endif /* NEWGRF_CALLBACKS_H */