/* $Id$ */

#ifndef SLOPE_H
#define SLOPE_H

typedef 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;

static inline bool IsSteepSlope(Slope s)
{
	return (s & SLOPE_STEEP) != 0;
}

static inline Slope ComplementSlope(Slope s)
{
	assert(!IsSteepSlope(s));
	return (Slope)(0xF ^ s);
}

#endif