/* $Id$ */ /** @file slope.h Definitions of a slope. * This file defines the enumeration and helper functions for handling * the slope info of a tile. */ #ifndef SLOPE_H #define SLOPE_H /** * Enumeration of tile corners */ enum Corner { CORNER_W = 0, CORNER_S = 1, CORNER_E = 2, CORNER_N = 3, CORNER_END, CORNER_INVALID = 0xFF }; /** * Enumeration for the slope-type. * * This enumeration use the chars N,E,S,W corresponding the * direction north, east, south and west. The top corner of a tile * is the north-part of the tile. The whole slope is encoded with * 5 bits, 4 bits for each corner and 1 bit for a steep-flag. * * For halftile slopes an extra 3 bits are used to represent this * properly; 1 bit for a halftile-flag and 2 bits to encode which * extra side (corner) is leveled when the slope of the first 5 * bits is applied. This means that there can only be one leveled * slope for steep slopes, which is logical because two leveled * slopes would mean that it is not a steep slope as halftile * slopes only span one height level. */ enum Slope { SLOPE_FLAT = 0x00, ///< a flat tile SLOPE_W = 0x01, ///< the west corner of the tile is raised SLOPE_S = 0x02, ///< the south corner of the tile is raised SLOPE_E = 0x04, ///< the east corner of the tile is raised SLOPE_N = 0x08, ///< the north corner of the tile is raised SLOPE_STEEP = 0x10, ///< indicates the slope is steep SLOPE_NW = SLOPE_N | SLOPE_W, ///< north and west corner are raised SLOPE_SW = SLOPE_S | SLOPE_W, ///< south and west corner are raised SLOPE_SE = SLOPE_S | SLOPE_E, ///< south and east corner are raised SLOPE_NE = SLOPE_N | SLOPE_E, ///< north and east corner are raised SLOPE_EW = SLOPE_E | SLOPE_W, ///< east and west corner are raised SLOPE_NS = SLOPE_N | SLOPE_S, ///< north and south corner are raised SLOPE_ELEVATED = SLOPE_N | SLOPE_E | SLOPE_S | SLOPE_W, ///< all corner are raised, similar to SLOPE_FLAT SLOPE_NWS = SLOPE_N | SLOPE_W | SLOPE_S, ///< north, west and south corner are raised SLOPE_WSE = SLOPE_W | SLOPE_S | SLOPE_E, ///< west, south and east corner are raised SLOPE_SEN = SLOPE_S | SLOPE_E | SLOPE_N, ///< south, east and north corner are raised SLOPE_ENW = SLOPE_E | SLOPE_N | SLOPE_W, ///< east, north and west corner are raised SLOPE_STEEP_W = SLOPE_STEEP | SLOPE_NWS, ///< a steep slope falling to east (from west) SLOPE_STEEP_S = SLOPE_STEEP | SLOPE_WSE, ///< a steep slope falling to north (from south) SLOPE_STEEP_E = SLOPE_STEEP | SLOPE_SEN, ///< a steep slope falling to west (from east) SLOPE_STEEP_N = SLOPE_STEEP | SLOPE_ENW, ///< a steep slope falling to south (from north) SLOPE_HALFTILE = 0x20, ///< one halftile is leveled (non continuous slope) SLOPE_HALFTILE_MASK = 0xE0, ///< three bits used for halftile slopes SLOPE_HALFTILE_W = SLOPE_HALFTILE | (CORNER_W << 6), ///< the west halftile is leveled (non continuous slope) SLOPE_HALFTILE_S = SLOPE_HALFTILE | (CORNER_S << 6), ///< the south halftile is leveled (non continuous slope) SLOPE_HALFTILE_E = SLOPE_HALFTILE | (CORNER_E << 6), ///< the east halftile is leveled (non continuous slope) SLOPE_HALFTILE_N = SLOPE_HALFTILE | (CORNER_N << 6), ///< the north halftile is leveled (non continuous slope) }; /** * Rangecheck for Corner enumeration. * * @param corner A #Corner. * @return true iff corner is in a valid range. */ static inline bool IsValidCorner(Corner corner) { return IS_INT_INSIDE(corner, 0, CORNER_END); } /** * Checks if a slope is steep. * * @param s The given #Slope. * @return True if the slope is steep, else false. */ static inline bool IsSteepSlope(Slope s) { return (s & SLOPE_STEEP) != 0; } /** * Checks for non-continuous slope on halftile foundations. * * @param s The given #Slope. * @return True if the slope is non-continuous, else false. */ static inline bool IsHalftileSlope(Slope s) { return (s & SLOPE_HALFTILE) != 0; } /** * Return the complement of a slope. * * This method returns the complement of a slope. The complement of a * slope is a slope with raised corner which aren't raised in the given * slope. * * @pre The slope must neither be steep nor a halftile slope. * @param s The #Slope to get the complement. * @return a complement Slope of the given slope. */ static inline Slope ComplementSlope(Slope s) { assert(!IsSteepSlope(s) && !IsHalftileSlope(s)); return (Slope)(0xF ^ s); } /** * Tests if a slope has a highest corner (i.e. one corner raised or a steep slope). * * Note: A halftile slope is ignored. * * @param s The #Slope. * @return true iff the slope has a highest corner. */ static inline bool HasSlopeHighestCorner(Slope s) { s = (Slope)(s & ~SLOPE_HALFTILE_MASK); return IsSteepSlope(s) || (s == SLOPE_W) || (s == SLOPE_S) || (s == SLOPE_E) || (s == SLOPE_N); } /** * Returns the highest corner of a slope (one corner raised or a steep slope). * * @pre The slope must be a slope with one corner raised or a steep slope. A halftile slope is ignored. * @param s The #Slope. * @return Highest corner. */ static inline Corner GetHighestSlopeCorner(Slope s) { switch (s & ~SLOPE_HALFTILE_MASK) { case SLOPE_W: case SLOPE_STEEP_W: return CORNER_W; case SLOPE_S: case SLOPE_STEEP_S: return CORNER_S; case SLOPE_E: case SLOPE_STEEP_E: return CORNER_E; case SLOPE_N: case SLOPE_STEEP_N: return CORNER_N; default: NOT_REACHED(); } } /** * Returns the leveled halftile of a halftile slope. * * @pre The slope must be a halftile slope. * @param s The #Slope. * @return The corner of the leveled halftile. */ static inline Corner GetHalftileSlopeCorner(Slope s) { assert(IsHalftileSlope(s)); return (Corner)((s >> 6) & 3); } /** * Returns the height of the highest corner of a slope relative to TileZ (= minimal height) * * @param s The #Slope. * @return Relative height of highest corner. */ static inline uint GetSlopeMaxZ(Slope s) { if (s == SLOPE_FLAT) return 0; if (IsSteepSlope(s)) return 2 * TILE_HEIGHT; return TILE_HEIGHT; } /** * Returns the opposite corner. * * @param corner A #Corner. * @return The opposite corner to "corner". */ static inline Corner OppositeCorner(Corner corner) { return (Corner)(corner ^ 2); } /** * Returns the slope with a specific corner raised. * * @param corner The #Corner. * @return The #Slope with corner "corner" raised. */ static inline Slope SlopeWithOneCornerRaised(Corner corner) { assert(IsValidCorner(corner)); return (Slope)(1 << corner); } /** * Returns the slope with all except one corner raised. * * @param corner The #Corner. * @return The #Slope with all corners but "corner" raised. */ static inline Slope SlopeWithThreeCornersRaised(Corner corner) { return ComplementSlope(SlopeWithOneCornerRaised(corner)); } /** * Adds a halftile slope to a slope. * * @param s #Slope without a halftile slope. * @param corner The #Corner of the halftile. * @return The #Slope s with the halftile slope added. */ static inline Slope HalftileSlope(Slope s, Corner corner) { assert(IsValidCorner(corner)); return (Slope)(s | SLOPE_HALFTILE | (corner << 6)); } /** * Enumeration for Foundations. */ enum Foundation { FOUNDATION_NONE, ///< The tile has no foundation, the slope remains unchanged. FOUNDATION_LEVELED, ///< The tile is leveled up to a flat slope. FOUNDATION_INCLINED_X, ///< The tile has an along X-axis inclined foundation. FOUNDATION_INCLINED_Y, ///< The tile has an along Y-axis inclined foundation. FOUNDATION_STEEP_LOWER, ///< The tile has a steep slope. The lowest corner is raised by a foundation to allow building railroad on the lower halftile. /* Halftile foundations */ FOUNDATION_STEEP_BOTH, ///< The tile has a steep slope. The lowest corner is raised by a foundation and the upper halftile is leveled. FOUNDATION_HALFTILE_W, ///< Level west halftile non-continuously. FOUNDATION_HALFTILE_S, ///< Level south halftile non-continuously. FOUNDATION_HALFTILE_E, ///< Level east halftile non-continuously. FOUNDATION_HALFTILE_N, ///< Level north halftile non-continuously. /* Special anti-zig-zag foundations for single horizontal/vertical track */ FOUNDATION_RAIL_W, ///< Foundation for TRACK_BIT_LEFT, but not a leveled foundation. FOUNDATION_RAIL_S, ///< Foundation for TRACK_BIT_LOWER, but not a leveled foundation. FOUNDATION_RAIL_E, ///< Foundation for TRACK_BIT_RIGHT, but not a leveled foundation. FOUNDATION_RAIL_N, ///< Foundation for TRACK_BIT_UPPER, but not a leveled foundation. FOUNDATION_INVALID = 0xFF ///< Used inside "rail_cmd.cpp" to indicate invalid slope/track combination. }; /** * Tests for FOUNDATION_NONE. * * @param f Maybe a #Foundation. * @return true iff f is a foundation. */ static inline bool IsFoundation(Foundation f) { return f != FOUNDATION_NONE; } /** * Tests if the foundation is a leveled foundation. * * @param f The #Foundation. * @return true iff f is a leveled foundation. */ static inline bool IsLeveledFoundation(Foundation f) { return f == FOUNDATION_LEVELED; } /** * Tests if the foundation is an inclined foundation. * * @param f The #Foundation. * @return true iff f is an inclined foundation. */ static inline bool IsInclinedFoundation(Foundation f) { return (f == FOUNDATION_INCLINED_X) || (f == FOUNDATION_INCLINED_Y); } /** * Tests if a foundation is a non-continuous foundation, i.e. halftile-foundation or FOUNDATION_STEEP_BOTH. * * @param f The #Foundation. * @return true iff f is a non-continuous foundation */ static inline bool IsNonContinuousFoundation(Foundation f) { return IS_INT_INSIDE(f, FOUNDATION_STEEP_BOTH, FOUNDATION_HALFTILE_N + 1); } /** * Returns the halftile corner of a halftile-foundation * * @pre f != FOUNDATION_STEEP_BOTH * * @param f The #Foundation. * @return The #Corner with track. */ static inline Corner GetHalftileFoundationCorner(Foundation f) { assert(IS_INT_INSIDE(f, FOUNDATION_HALFTILE_W, FOUNDATION_HALFTILE_N + 1)); return (Corner)(f - FOUNDATION_HALFTILE_W); } /** * Tests if a foundation is a special rail foundation for single horizontal/vertical track. * * @param f The #Foundation. * @return true iff f is a special rail foundation for single horizontal/vertical track. */ static inline bool IsSpecialRailFoundation(Foundation f) { return IS_INT_INSIDE(f, FOUNDATION_RAIL_W, FOUNDATION_RAIL_N + 1); } /** * Returns the track corner of a special rail foundation * * @param f The #Foundation. * @return The #Corner with track. */ static inline Corner GetRailFoundationCorner(Foundation f) { assert(IsSpecialRailFoundation(f)); return (Corner)(f - FOUNDATION_RAIL_W); } /** * Returns the foundation needed to flatten a slope. * The returned foundation is either FOUNDATION_NONE if the tile was already flat, or FOUNDATION_LEVELED. * * @pre The slope must not be steep. * @param s The current #Slope. * @return The needed #Foundation. */ static inline Foundation FlatteningFoundation(Slope s) { assert(!IsSteepSlope(s)); return (s == SLOPE_FLAT ? FOUNDATION_NONE : FOUNDATION_LEVELED); } /** * Returns the along a specific axis inclined foundation. * * @param axis The #Axis. * @return The needed #Foundation. */ static inline Foundation InclinedFoundation(Axis axis) { return (axis == AXIS_X ? FOUNDATION_INCLINED_X : FOUNDATION_INCLINED_Y); } /** * Returns the halftile foundation for single horizontal/vertical track. * * @param corner The #Corner with the track. * @return The wanted #Foundation. */ static inline Foundation HalftileFoundation(Corner corner) { assert(IsValidCorner(corner)); return (Foundation)(FOUNDATION_HALFTILE_W + corner); } /** * Returns the special rail foundation for single horizontal/vertical track. * * @param corner The #Corner with the track. * @return The wanted #Foundation. */ static inline Foundation SpecialRailFoundation(Corner corner) { assert(IsValidCorner(corner)); return (Foundation)(FOUNDATION_RAIL_W + corner); } #endif /* SLOPE_H */