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/* $Id$ */

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#ifndef SLOPE_H

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#define SLOPE_H

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typedef enum Slope {

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	SLOPE_FLAT     = 0x00,

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	SLOPE_W        = 0x01,

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	SLOPE_S        = 0x02,

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	SLOPE_E        = 0x04,

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	SLOPE_N        = 0x08,

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	SLOPE_STEEP    = 0x10,

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	SLOPE_NW       = SLOPE_N | SLOPE_W,

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	SLOPE_SW       = SLOPE_S | SLOPE_W,

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	SLOPE_SE       = SLOPE_S | SLOPE_E,

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	SLOPE_NE       = SLOPE_N | SLOPE_E,

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	SLOPE_EW       = SLOPE_E | SLOPE_W,

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	SLOPE_NS       = SLOPE_N | SLOPE_S,

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	SLOPE_ELEVATED = SLOPE_N | SLOPE_E | SLOPE_S | SLOPE_W,

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	SLOPE_NWS      = SLOPE_N | SLOPE_W | SLOPE_S,

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	SLOPE_WSE      = SLOPE_W | SLOPE_S | SLOPE_E,

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	SLOPE_SEN      = SLOPE_S | SLOPE_E | SLOPE_N,

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	SLOPE_ENW      = SLOPE_E | SLOPE_N | SLOPE_W,

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	SLOPE_STEEP_W  = SLOPE_STEEP | SLOPE_NWS,

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	SLOPE_STEEP_S  = SLOPE_STEEP | SLOPE_WSE,

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	SLOPE_STEEP_E  = SLOPE_STEEP | SLOPE_SEN,

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	SLOPE_STEEP_N  = SLOPE_STEEP | SLOPE_ENW

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} Slope;

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static inline bool IsSteepSlope(Slope s)

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{

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	return (s & SLOPE_STEEP) != 0;

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}

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static inline Slope ComplementSlope(Slope s)

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{

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	assert(!IsSteepSlope(s));

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	return (Slope)(0xF ^ s);

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}

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#endif