/* $Id$ */ /* * This file is part of OpenTTD. * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2. * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>. */ /** @file slope_func.h Functions related to slopes. */ #ifndef SLOPE_FUNC_H #define SLOPE_FUNC_H #include "core/math_func.hpp" #include "slope_type.h" #include "direction_type.h" #include "tile_type.h" /** * Rangecheck for Corner enumeration. * * @param corner A #Corner. * @return true iff corner is in a valid range. */ static inline bool IsValidCorner(Corner corner) { return IsInsideMM(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; } /** * Removes a halftile slope from a slope * * Non-halftile slopes remain unmodified. * * @param s A #Slope. * @return The slope s without it's halftile slope. */ static inline Slope RemoveHalftileSlope(Slope s) { return s & ~SLOPE_HALFTILE_MASK; } /** * 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 s ^ SLOPE_ELEVATED; } /** * Tests if a specific slope has exactly one corner raised. * * @param s The #Slope * @return true iff exactly one corner is raised */ static inline bool IsSlopeWithOneCornerRaised(Slope s) { return (s == SLOPE_W) || (s == SLOPE_S) || (s == SLOPE_E) || (s == SLOPE_N); } /** * 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); } /** * 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 = RemoveHalftileSlope(s); return IsSteepSlope(s) || IsSlopeWithOneCornerRaised(s); } /** * 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 (RemoveHalftileSlope(s)) { 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); } /** * Tests if a specific slope has exactly three corners raised. * * @param s The #Slope * @return true iff exactly three corners are raised */ static inline bool IsSlopeWithThreeCornersRaised(Slope s) { return !IsHalftileSlope(s) && !IsSteepSlope(s) && IsSlopeWithOneCornerRaised(ComplementSlope(s)); } /** * 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)); } /** * Returns a specific steep slope * * @param corner A #Corner. * @return The steep #Slope with "corner" as highest corner. */ static inline Slope SteepSlope(Corner corner) { return SLOPE_STEEP | SlopeWithThreeCornersRaised(OppositeCorner(corner)); } /** * Tests if a specific slope is an inclined slope. * * @param s The #Slope * @return true iff the slope is inclined. */ static inline bool IsInclinedSlope(Slope s) { return (s == SLOPE_NW) || (s == SLOPE_SW) || (s == SLOPE_SE) || (s == SLOPE_NE); } /** * Returns the direction of an inclined slope. * * @param s A #Slope * @return The direction the slope goes up in. Or INVALID_DIAGDIR if the slope is not an inclined slope. */ static inline DiagDirection GetInclinedSlopeDirection(Slope s) { switch (s) { case SLOPE_NE: return DIAGDIR_NE; case SLOPE_SE: return DIAGDIR_SE; case SLOPE_SW: return DIAGDIR_SW; case SLOPE_NW: return DIAGDIR_NW; default: return INVALID_DIAGDIR; } } /** * Returns the slope, that is inclined in a specific direction. * * @param dir A #DiagDirection * @return The #Slope that goes up in direction dir. */ static inline Slope InclinedSlope(DiagDirection dir) { switch (dir) { case DIAGDIR_NE: return SLOPE_NE; case DIAGDIR_SE: return SLOPE_SE; case DIAGDIR_SW: return SLOPE_SW; case DIAGDIR_NW: return SLOPE_NW; default: NOT_REACHED(); } } /** * 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)); } /** * 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 IsInsideMM(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(IsInsideMM(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 IsInsideMM(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. * * @param s The current #Slope. * @return The needed #Foundation. */ static inline Foundation FlatteningFoundation(Slope 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_FUNC_H */