--- a/src/slope.h Tue Jul 31 23:31:45 2007 +0000
+++ b/src/slope.h Fri Aug 03 18:10:15 2007 +0000
@@ -1,43 +1,164 @@
/* $Id$ */
-/** @file slope.h */
+/** @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 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.
+ */
enum Slope {
- SLOPE_FLAT = 0x00,
- SLOPE_W = 0x01,
- SLOPE_S = 0x02,
- SLOPE_E = 0x04,
- SLOPE_N = 0x08,
- SLOPE_STEEP = 0x10,
- SLOPE_NW = SLOPE_N | SLOPE_W,
- SLOPE_SW = SLOPE_S | SLOPE_W,
- SLOPE_SE = SLOPE_S | SLOPE_E,
- SLOPE_NE = SLOPE_N | SLOPE_E,
- SLOPE_EW = SLOPE_E | SLOPE_W,
- SLOPE_NS = SLOPE_N | SLOPE_S,
- SLOPE_ELEVATED = SLOPE_N | SLOPE_E | SLOPE_S | SLOPE_W,
- SLOPE_NWS = SLOPE_N | SLOPE_W | SLOPE_S,
- SLOPE_WSE = SLOPE_W | SLOPE_S | SLOPE_E,
- SLOPE_SEN = SLOPE_S | SLOPE_E | SLOPE_N,
- SLOPE_ENW = SLOPE_E | SLOPE_N | SLOPE_W,
- SLOPE_STEEP_W = SLOPE_STEEP | SLOPE_NWS,
- SLOPE_STEEP_S = SLOPE_STEEP | SLOPE_WSE,
- SLOPE_STEEP_E = SLOPE_STEEP | SLOPE_SEN,
- SLOPE_STEEP_N = SLOPE_STEEP | SLOPE_ENW
+ 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)
};
+/**
+ * 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;
}
+/**
+ * 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 not be steep.
+ * @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));
return (Slope)(0xF ^ 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.
+ * @param s The #Slope.
+ * @return Number of the highest corner. (0 west, 1 south, 2 east, 3 north)
+ */
+static inline byte GetHighestSlopeCorner(Slope s)
+{
+ switch (s) {
+ case SLOPE_W:
+ case SLOPE_STEEP_W: return 0;
+ case SLOPE_S:
+ case SLOPE_STEEP_S: return 1;
+ case SLOPE_E:
+ case SLOPE_STEEP_E: return 2;
+ case SLOPE_N:
+ case SLOPE_STEEP_N: return 3;
+ default: NOT_REACHED();
+ }
+}
+
+
+/**
+ * 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 lowerst corner is raised by a foundation to allow building railroad on the lower halftile.
+ FOUNDATION_STEEP_HIGHER, ///< The tile has a steep slope. Three corners are raised by a foundation to allow building railroad on the higher halftile.
+};
+
+/**
+ * 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);
+}
+
+/**
+ * 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);
+}
+
#endif /* SLOPE_H */