tron@3636: /* $Id$ */
tron@3636: 
truelight@7805: /** @file slope.h Definitions of a slope.
truelight@7805:  * This file defines the enumeration and helper functions for handling
truelight@7805:  * the slope info of a tile.
truelight@7805:  */
belugas@6916: 
tron@3636: #ifndef SLOPE_H
tron@3636: #define SLOPE_H
tron@3636: 
truelight@7805: /**
rubidium@8260:  * Enumeration of tile corners
rubidium@8260:  */
rubidium@8260: enum Corner {
rubidium@8260: 	CORNER_W = 0,
rubidium@8260: 	CORNER_S = 1,
rubidium@8260: 	CORNER_E = 2,
rubidium@8260: 	CORNER_N = 3,
rubidium@8260: 	CORNER_END
rubidium@8260: };
rubidium@8260: 
rubidium@8260: /**
truelight@7805:  * Enumeration for the slope-type.
truelight@7805:  *
truelight@7805:  * This enumeration use the chars N,E,S,W corresponding the
truelight@7805:  * direction north, east, south and west. The top corner of a tile
truelight@7805:  * is the north-part of the tile. The whole slope is encoded with
truelight@7805:  * 5 bits, 4 bits for each corner and 1 bit for a steep-flag.
rubidium@8260:  *
rubidium@8260:  * For halftile slopes an extra 3 bits are used to represent this
rubidium@8260:  * properly; 1 bit for a halftile-flag and 2 bits to encode which
rubidium@8260:  * extra side (corner) is leveled when the slope of the first 5
rubidium@8260:  * bits is applied. This means that there can only be one leveled
rubidium@8260:  * slope for steep slopes, which is logical because two leveled
rubidium@8260:  * slopes would mean that it is not a steep slope as halftile
rubidium@8260:  * slopes only span one height level.
truelight@7805:  */
rubidium@6574: enum Slope {
truelight@7805: 	SLOPE_FLAT     = 0x00,                                  ///< a flat tile
truelight@7805: 	SLOPE_W        = 0x01,                                  ///< the west corner of the tile is raised
truelight@7805: 	SLOPE_S        = 0x02,                                  ///< the south corner of the tile is raised
truelight@7805: 	SLOPE_E        = 0x04,                                  ///< the east corner of the tile is raised
truelight@7805: 	SLOPE_N        = 0x08,                                  ///< the north corner of the tile is raised
truelight@7805: 	SLOPE_STEEP    = 0x10,                                  ///< indicates the slope is steep
truelight@7805: 	SLOPE_NW       = SLOPE_N | SLOPE_W,                     ///< north and west corner are raised
truelight@7805: 	SLOPE_SW       = SLOPE_S | SLOPE_W,                     ///< south and west corner are raised
truelight@7805: 	SLOPE_SE       = SLOPE_S | SLOPE_E,                     ///< south and east corner are raised
truelight@7805: 	SLOPE_NE       = SLOPE_N | SLOPE_E,                     ///< north and east corner are raised
truelight@7805: 	SLOPE_EW       = SLOPE_E | SLOPE_W,                     ///< east and west corner are raised
truelight@7805: 	SLOPE_NS       = SLOPE_N | SLOPE_S,                     ///< north and south corner are raised
truelight@7805: 	SLOPE_ELEVATED = SLOPE_N | SLOPE_E | SLOPE_S | SLOPE_W, ///< all corner are raised, similar to SLOPE_FLAT
truelight@7805: 	SLOPE_NWS      = SLOPE_N | SLOPE_W | SLOPE_S,           ///< north, west and south corner are raised
truelight@7805: 	SLOPE_WSE      = SLOPE_W | SLOPE_S | SLOPE_E,           ///< west, south and east corner are raised
truelight@7805: 	SLOPE_SEN      = SLOPE_S | SLOPE_E | SLOPE_N,           ///< south, east and north corner are raised
truelight@7805: 	SLOPE_ENW      = SLOPE_E | SLOPE_N | SLOPE_W,           ///< east, north and west corner are raised
truelight@7805: 	SLOPE_STEEP_W  = SLOPE_STEEP | SLOPE_NWS,               ///< a steep slope falling to east (from west)
truelight@7805: 	SLOPE_STEEP_S  = SLOPE_STEEP | SLOPE_WSE,               ///< a steep slope falling to north (from south)
truelight@7805: 	SLOPE_STEEP_E  = SLOPE_STEEP | SLOPE_SEN,               ///< a steep slope falling to west (from east)
rubidium@8260: 	SLOPE_STEEP_N  = SLOPE_STEEP | SLOPE_ENW,               ///< a steep slope falling to south (from north)
tron@3636: 
rubidium@8260: 	SLOPE_HALFTILE = 0x20,                                  ///< one halftile is leveled (non continuous slope)
rubidium@8260: 	SLOPE_HALFTILE_MASK = 0xE0,                             ///< three bits used for halftile slopes
rubidium@8260: 	SLOPE_HALFTILE_W = SLOPE_HALFTILE | (CORNER_W << 6),    ///< the west halftile is leveled (non continuous slope)
rubidium@8260: 	SLOPE_HALFTILE_S = SLOPE_HALFTILE | (CORNER_S << 6),    ///< the south halftile is leveled (non continuous slope)
rubidium@8260: 	SLOPE_HALFTILE_E = SLOPE_HALFTILE | (CORNER_E << 6),    ///< the east halftile is leveled (non continuous slope)
rubidium@8260: 	SLOPE_HALFTILE_N = SLOPE_HALFTILE | (CORNER_N << 6),    ///< the north halftile is leveled (non continuous slope)
rubidium@8174: };
rubidium@8174: 
rubidium@8174: /**
rubidium@8199:  * Rangecheck for Corner enumeration.
rubidium@8199:  *
rubidium@8199:  * @param corner A #Corner.
rubidium@8199:  * @return true iff corner is in a valid range.
rubidium@8199:  */
rubidium@8199: static inline bool IsValidCorner(Corner corner)
rubidium@8199: {
rubidium@8199: 	return IS_INT_INSIDE(corner, 0, CORNER_END);
rubidium@8199: }
rubidium@8199: 
rubidium@8199: /**
truelight@7805:  * Checks if a slope is steep.
truelight@7805:  *
truelight@7805:  * @param s The given #Slope.
truelight@7805:  * @return True if the slope is steep, else false.
truelight@7805:  */
tron@3636: static inline bool IsSteepSlope(Slope s)
tron@3636: {
tron@3636: 	return (s & SLOPE_STEEP) != 0;
tron@3636: }
tron@3636: 
truelight@7805: /**
rubidium@8260:  * Checks for non-continuous slope on halftile foundations.
rubidium@8260:  *
rubidium@8260:  * @param s The given #Slope.
rubidium@8260:  * @return True if the slope is non-continuous, else false.
rubidium@8260:  */
rubidium@8260: static inline bool IsHalftileSlope(Slope s)
rubidium@8260: {
rubidium@8260: 	return (s & SLOPE_HALFTILE) != 0;
rubidium@8260: }
rubidium@8260: 
rubidium@8260: /**
truelight@7805:  * Return the complement of a slope.
truelight@7805:  *
truelight@7805:  * This method returns the complement of a slope. The complement of a
truelight@7805:  * slope is a slope with raised corner which aren't raised in the given
truelight@7805:  * slope.
truelight@7805:  *
rubidium@8260:  * @pre The slope must neither be steep nor a halftile slope.
truelight@7805:  * @param s The #Slope to get the complement.
truelight@7805:  * @return a complement Slope of the given slope.
truelight@7805:  */
tron@3636: static inline Slope ComplementSlope(Slope s)
tron@3636: {
rubidium@8260: 	assert(!IsSteepSlope(s) && !IsHalftileSlope(s));
tron@3636: 	return (Slope)(0xF ^ s);
tron@3636: }
tron@3636: 
rubidium@7831: /**
rubidium@8199:  * Tests if a slope has a highest corner (i.e. one corner raised or a steep slope).
rubidium@8199:  *
rubidium@8260:  * Note: A halftile slope is ignored.
rubidium@8260:  *
rubidium@8199:  * @param s The #Slope.
rubidium@8199:  * @return  true iff the slope has a highest corner.
rubidium@8199:  */
rubidium@8199: static inline bool HasSlopeHighestCorner(Slope s)
rubidium@8199: {
rubidium@8260: 	s = (Slope)(s & ~SLOPE_HALFTILE_MASK);
rubidium@8199: 	return IsSteepSlope(s) || (s == SLOPE_W) || (s == SLOPE_S) || (s == SLOPE_E) || (s == SLOPE_N);
rubidium@8199: }
rubidium@8199: 
rubidium@8199: /**
rubidium@7831:  * Returns the highest corner of a slope (one corner raised or a steep slope).
rubidium@7831:  *
rubidium@8260:  * @pre      The slope must be a slope with one corner raised or a steep slope. A halftile slope is ignored.
rubidium@7831:  * @param s  The #Slope.
rubidium@8174:  * @return   Highest corner.
rubidium@7831:  */
rubidium@8174: static inline Corner GetHighestSlopeCorner(Slope s)
rubidium@7831: {
rubidium@8260: 	switch (s & ~SLOPE_HALFTILE_MASK) {
rubidium@7831: 		case SLOPE_W:
rubidium@8174: 		case SLOPE_STEEP_W: return CORNER_W;
rubidium@7831: 		case SLOPE_S:
rubidium@8174: 		case SLOPE_STEEP_S: return CORNER_S;
rubidium@7831: 		case SLOPE_E:
rubidium@8174: 		case SLOPE_STEEP_E: return CORNER_E;
rubidium@7831: 		case SLOPE_N:
rubidium@8174: 		case SLOPE_STEEP_N: return CORNER_N;
rubidium@7831: 		default: NOT_REACHED();
rubidium@7831: 	}
rubidium@7831: }
rubidium@7831: 
rubidium@8078: /**
rubidium@8260:  * Returns the leveled halftile of a halftile slope.
rubidium@8260:  *
rubidium@8260:  * @pre     The slope must be a halftile slope.
rubidium@8260:  * @param s The #Slope.
rubidium@8260:  * @return  The corner of the leveled halftile.
rubidium@8260:  */
rubidium@8260: static inline Corner GetHalftileSlopeCorner(Slope s)
rubidium@8260: {
rubidium@8260: 	assert(IsHalftileSlope(s));
rubidium@8260: 	return (Corner)((s >> 6) & 3);
rubidium@8260: }
rubidium@8260: 
rubidium@8260: /**
rubidium@8078:  * Returns the height of the highest corner of a slope relative to TileZ (= minimal height)
rubidium@8078:  *
rubidium@8078:  * @param s The #Slope.
rubidium@8078:  * @return Relative height of highest corner.
rubidium@8078:  */
rubidium@8078: static inline uint GetSlopeMaxZ(Slope s)
rubidium@8078: {
rubidium@8078: 	if (s == SLOPE_FLAT) return 0;
rubidium@8078: 	if (IsSteepSlope(s)) return 2 * TILE_HEIGHT;
rubidium@8078: 	return TILE_HEIGHT;
rubidium@8078: }
rubidium@8078: 
rubidium@8174: /**
rubidium@8174:  * Returns the opposite corner.
rubidium@8174:  *
rubidium@8174:  * @param corner A #Corner.
rubidium@8174:  * @return The opposite corner to "corner".
rubidium@8174:  */
rubidium@8174: static inline Corner OppositeCorner(Corner corner)
rubidium@8174: {
rubidium@8174: 	return (Corner)(corner ^ 2);
rubidium@8174: }
rubidium@8174: 
rubidium@8174: /**
rubidium@8174:  * Returns the slope with a specific corner raised.
rubidium@8174:  *
rubidium@8174:  * @param corner The #Corner.
rubidium@8174:  * @return The #Slope with corner "corner" raised.
rubidium@8174:  */
rubidium@8174: static inline Slope SlopeWithOneCornerRaised(Corner corner)
rubidium@8174: {
rubidium@8199: 	assert(IsValidCorner(corner));
rubidium@8174: 	return (Slope)(1 << corner);
rubidium@8174: }
rubidium@8174: 
rubidium@8174: /**
rubidium@8174:  * Returns the slope with all except one corner raised.
rubidium@8174:  *
rubidium@8174:  * @param corner The #Corner.
rubidium@8174:  * @return The #Slope with all corners but "corner" raised.
rubidium@8174:  */
rubidium@8174: static inline Slope SlopeWithThreeCornersRaised(Corner corner)
rubidium@8174: {
rubidium@8174: 	return ComplementSlope(SlopeWithOneCornerRaised(corner));
rubidium@8174: }
rubidium@8174: 
rubidium@8260: /**
rubidium@8260:  * Adds a halftile slope to a slope.
rubidium@8260:  *
rubidium@8260:  * @param s #Slope without a halftile slope.
rubidium@8260:  * @param corner The #Corner of the halftile.
rubidium@8260:  * @return The #Slope s with the halftile slope added.
rubidium@8260:  */
rubidium@8260: static inline Slope HalftileSlope(Slope s, Corner corner)
rubidium@8260: {
rubidium@8260: 	assert(IsValidCorner(corner));
rubidium@8260: 	return (Slope)(s | SLOPE_HALFTILE | (corner << 6));
rubidium@8260: }
rubidium@8260: 
rubidium@7831: 
rubidium@7831: /**
rubidium@7831:  * Enumeration for Foundations.
rubidium@7831:  */
rubidium@7831: enum Foundation {
rubidium@7831: 	FOUNDATION_NONE,             ///< The tile has no foundation, the slope remains unchanged.
rubidium@7831: 	FOUNDATION_LEVELED,          ///< The tile is leveled up to a flat slope.
rubidium@7831: 	FOUNDATION_INCLINED_X,       ///< The tile has an along X-axis inclined foundation.
rubidium@7831: 	FOUNDATION_INCLINED_Y,       ///< The tile has an along Y-axis inclined foundation.
rubidium@7831: 	FOUNDATION_STEEP_LOWER,      ///< The tile has a steep slope. The lowerst corner is raised by a foundation to allow building railroad on the lower halftile.
rubidium@7831: 	FOUNDATION_STEEP_HIGHER,     ///< The tile has a steep slope. Three corners are raised by a foundation to allow building railroad on the higher halftile.
rubidium@8199: 
rubidium@8199: 	FOUNDATION_INVALID = 0xFF    ///< Used inside "rail_cmd.cpp" to indicate invalid slope/track combination.
rubidium@7831: };
rubidium@7831: 
rubidium@7831: /**
rubidium@7831:  * Tests for FOUNDATION_NONE.
rubidium@7831:  *
rubidium@7831:  * @param f  Maybe a #Foundation.
rubidium@7831:  * @return   true iff f is a foundation.
rubidium@7831:  */
rubidium@7831: static inline bool IsFoundation(Foundation f)
rubidium@7831: {
rubidium@7831: 	return f != FOUNDATION_NONE;
rubidium@7831: }
rubidium@7831: 
rubidium@7831: /**
rubidium@7831:  * Tests if the foundation is a leveled foundation.
rubidium@7831:  *
rubidium@7831:  * @param f  The #Foundation.
rubidium@7831:  * @return   true iff f is a leveled foundation.
rubidium@7831:  */
rubidium@7831: static inline bool IsLeveledFoundation(Foundation f)
rubidium@7831: {
rubidium@7831: 	return f == FOUNDATION_LEVELED;
rubidium@7831: }
rubidium@7831: 
rubidium@7831: /**
rubidium@7831:  * Tests if the foundation is an inclined foundation.
rubidium@7831:  *
rubidium@7831:  * @param f  The #Foundation.
rubidium@7831:  * @return   true iff f is an inclined foundation.
rubidium@7831:  */
rubidium@7831: static inline bool IsInclinedFoundation(Foundation f)
rubidium@7831: {
rubidium@7831: 	return (f == FOUNDATION_INCLINED_X) || (f == FOUNDATION_INCLINED_Y);
rubidium@7831: }
rubidium@7831: 
rubidium@7831: /**
rubidium@7831:  * Returns the foundation needed to flatten a slope.
rubidium@7831:  * The returned foundation is either FOUNDATION_NONE if the tile was already flat, or FOUNDATION_LEVELED.
rubidium@7831:  *
rubidium@7831:  * @pre      The slope must not be steep.
rubidium@7831:  * @param s  The current #Slope.
rubidium@7831:  * @return   The needed #Foundation.
rubidium@7831:  */
rubidium@7831: static inline Foundation FlatteningFoundation(Slope s)
rubidium@7831: {
rubidium@7831: 	assert(!IsSteepSlope(s));
rubidium@7831: 	return (s == SLOPE_FLAT ? FOUNDATION_NONE : FOUNDATION_LEVELED);
rubidium@7831: }
rubidium@7831: 
rubidium@7831: /**
rubidium@7831:  * Returns the along a specific axis inclined foundation.
rubidium@7831:  *
rubidium@7831:  * @param axis  The #Axis.
rubidium@7831:  * @return      The needed #Foundation.
rubidium@7831:  */
rubidium@7831: static inline Foundation InclinedFoundation(Axis axis)
rubidium@7831: {
rubidium@7831: 	return (axis == AXIS_X ? FOUNDATION_INCLINED_X : FOUNDATION_INCLINED_Y);
rubidium@7831: }
rubidium@7831: 
peter1138@4666: #endif /* SLOPE_H */