1 /* $Id$ */ |
1 /* $Id$ */ |
2 |
2 |
3 /** @file slope.h */ |
3 /** @file slope.h Definitions of a slope. |
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4 * This file defines the enumeration and helper functions for handling |
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5 * the slope info of a tile. |
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6 */ |
4 |
7 |
5 #ifndef SLOPE_H |
8 #ifndef SLOPE_H |
6 #define SLOPE_H |
9 #define SLOPE_H |
7 |
10 |
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11 /** |
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12 * Enumeration for the slope-type. |
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13 * |
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14 * This enumeration use the chars N,E,S,W corresponding the |
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15 * direction north, east, south and west. The top corner of a tile |
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16 * is the north-part of the tile. The whole slope is encoded with |
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17 * 5 bits, 4 bits for each corner and 1 bit for a steep-flag. |
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18 */ |
8 enum Slope { |
19 enum Slope { |
9 SLOPE_FLAT = 0x00, |
20 SLOPE_FLAT = 0x00, ///< a flat tile |
10 SLOPE_W = 0x01, |
21 SLOPE_W = 0x01, ///< the west corner of the tile is raised |
11 SLOPE_S = 0x02, |
22 SLOPE_S = 0x02, ///< the south corner of the tile is raised |
12 SLOPE_E = 0x04, |
23 SLOPE_E = 0x04, ///< the east corner of the tile is raised |
13 SLOPE_N = 0x08, |
24 SLOPE_N = 0x08, ///< the north corner of the tile is raised |
14 SLOPE_STEEP = 0x10, |
25 SLOPE_STEEP = 0x10, ///< indicates the slope is steep |
15 SLOPE_NW = SLOPE_N | SLOPE_W, |
26 SLOPE_NW = SLOPE_N | SLOPE_W, ///< north and west corner are raised |
16 SLOPE_SW = SLOPE_S | SLOPE_W, |
27 SLOPE_SW = SLOPE_S | SLOPE_W, ///< south and west corner are raised |
17 SLOPE_SE = SLOPE_S | SLOPE_E, |
28 SLOPE_SE = SLOPE_S | SLOPE_E, ///< south and east corner are raised |
18 SLOPE_NE = SLOPE_N | SLOPE_E, |
29 SLOPE_NE = SLOPE_N | SLOPE_E, ///< north and east corner are raised |
19 SLOPE_EW = SLOPE_E | SLOPE_W, |
30 SLOPE_EW = SLOPE_E | SLOPE_W, ///< east and west corner are raised |
20 SLOPE_NS = SLOPE_N | SLOPE_S, |
31 SLOPE_NS = SLOPE_N | SLOPE_S, ///< north and south corner are raised |
21 SLOPE_ELEVATED = SLOPE_N | SLOPE_E | SLOPE_S | SLOPE_W, |
32 SLOPE_ELEVATED = SLOPE_N | SLOPE_E | SLOPE_S | SLOPE_W, ///< all corner are raised, similar to SLOPE_FLAT |
22 SLOPE_NWS = SLOPE_N | SLOPE_W | SLOPE_S, |
33 SLOPE_NWS = SLOPE_N | SLOPE_W | SLOPE_S, ///< north, west and south corner are raised |
23 SLOPE_WSE = SLOPE_W | SLOPE_S | SLOPE_E, |
34 SLOPE_WSE = SLOPE_W | SLOPE_S | SLOPE_E, ///< west, south and east corner are raised |
24 SLOPE_SEN = SLOPE_S | SLOPE_E | SLOPE_N, |
35 SLOPE_SEN = SLOPE_S | SLOPE_E | SLOPE_N, ///< south, east and north corner are raised |
25 SLOPE_ENW = SLOPE_E | SLOPE_N | SLOPE_W, |
36 SLOPE_ENW = SLOPE_E | SLOPE_N | SLOPE_W, ///< east, north and west corner are raised |
26 SLOPE_STEEP_W = SLOPE_STEEP | SLOPE_NWS, |
37 SLOPE_STEEP_W = SLOPE_STEEP | SLOPE_NWS, ///< a steep slope falling to east (from west) |
27 SLOPE_STEEP_S = SLOPE_STEEP | SLOPE_WSE, |
38 SLOPE_STEEP_S = SLOPE_STEEP | SLOPE_WSE, ///< a steep slope falling to north (from south) |
28 SLOPE_STEEP_E = SLOPE_STEEP | SLOPE_SEN, |
39 SLOPE_STEEP_E = SLOPE_STEEP | SLOPE_SEN, ///< a steep slope falling to west (from east) |
29 SLOPE_STEEP_N = SLOPE_STEEP | SLOPE_ENW |
40 SLOPE_STEEP_N = SLOPE_STEEP | SLOPE_ENW ///< a steep slope falling to south (from north) |
30 }; |
41 }; |
31 |
42 |
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43 /** |
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44 * Checks if a slope is steep. |
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45 * |
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46 * @param s The given #Slope. |
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47 * @return True if the slope is steep, else false. |
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48 */ |
32 static inline bool IsSteepSlope(Slope s) |
49 static inline bool IsSteepSlope(Slope s) |
33 { |
50 { |
34 return (s & SLOPE_STEEP) != 0; |
51 return (s & SLOPE_STEEP) != 0; |
35 } |
52 } |
36 |
53 |
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54 /** |
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55 * Return the complement of a slope. |
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56 * |
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57 * This method returns the complement of a slope. The complement of a |
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58 * slope is a slope with raised corner which aren't raised in the given |
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59 * slope. |
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60 * |
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61 * @pre The slope must not be steep. |
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62 * @param s The #Slope to get the complement. |
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63 * @return a complement Slope of the given slope. |
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64 */ |
37 static inline Slope ComplementSlope(Slope s) |
65 static inline Slope ComplementSlope(Slope s) |
38 { |
66 { |
39 assert(!IsSteepSlope(s)); |
67 assert(!IsSteepSlope(s)); |
40 return (Slope)(0xF ^ s); |
68 return (Slope)(0xF ^ s); |
41 } |
69 } |
42 |
70 |
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71 /** |
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72 * Returns the highest corner of a slope (one corner raised or a steep slope). |
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73 * |
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74 * @pre The slope must be a slope with one corner raised or a steep slope. |
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75 * @param s The #Slope. |
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76 * @return Number of the highest corner. (0 west, 1 south, 2 east, 3 north) |
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77 */ |
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78 static inline byte GetHighestSlopeCorner(Slope s) |
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79 { |
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80 switch (s) { |
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81 case SLOPE_W: |
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82 case SLOPE_STEEP_W: return 0; |
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83 case SLOPE_S: |
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84 case SLOPE_STEEP_S: return 1; |
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85 case SLOPE_E: |
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86 case SLOPE_STEEP_E: return 2; |
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87 case SLOPE_N: |
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88 case SLOPE_STEEP_N: return 3; |
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89 default: NOT_REACHED(); |
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90 } |
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91 } |
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92 |
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93 |
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94 /** |
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95 * Enumeration for Foundations. |
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96 */ |
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97 enum Foundation { |
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98 FOUNDATION_NONE, ///< The tile has no foundation, the slope remains unchanged. |
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99 FOUNDATION_LEVELED, ///< The tile is leveled up to a flat slope. |
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100 FOUNDATION_INCLINED_X, ///< The tile has an along X-axis inclined foundation. |
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101 FOUNDATION_INCLINED_Y, ///< The tile has an along Y-axis inclined foundation. |
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102 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. |
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103 FOUNDATION_STEEP_HIGHER, ///< The tile has a steep slope. Three corners are raised by a foundation to allow building railroad on the higher halftile. |
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104 }; |
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105 |
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106 /** |
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107 * Tests for FOUNDATION_NONE. |
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108 * |
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109 * @param f Maybe a #Foundation. |
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110 * @return true iff f is a foundation. |
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111 */ |
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112 static inline bool IsFoundation(Foundation f) |
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113 { |
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114 return f != FOUNDATION_NONE; |
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115 } |
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116 |
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117 /** |
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118 * Tests if the foundation is a leveled foundation. |
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119 * |
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120 * @param f The #Foundation. |
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121 * @return true iff f is a leveled foundation. |
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122 */ |
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123 static inline bool IsLeveledFoundation(Foundation f) |
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124 { |
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125 return f == FOUNDATION_LEVELED; |
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126 } |
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127 |
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128 /** |
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129 * Tests if the foundation is an inclined foundation. |
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130 * |
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131 * @param f The #Foundation. |
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132 * @return true iff f is an inclined foundation. |
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133 */ |
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134 static inline bool IsInclinedFoundation(Foundation f) |
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135 { |
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136 return (f == FOUNDATION_INCLINED_X) || (f == FOUNDATION_INCLINED_Y); |
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137 } |
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138 |
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139 /** |
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140 * Returns the foundation needed to flatten a slope. |
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141 * The returned foundation is either FOUNDATION_NONE if the tile was already flat, or FOUNDATION_LEVELED. |
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142 * |
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143 * @pre The slope must not be steep. |
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144 * @param s The current #Slope. |
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145 * @return The needed #Foundation. |
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146 */ |
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147 static inline Foundation FlatteningFoundation(Slope s) |
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148 { |
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149 assert(!IsSteepSlope(s)); |
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150 return (s == SLOPE_FLAT ? FOUNDATION_NONE : FOUNDATION_LEVELED); |
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151 } |
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152 |
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153 /** |
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154 * Returns the along a specific axis inclined foundation. |
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155 * |
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156 * @param axis The #Axis. |
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157 * @return The needed #Foundation. |
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158 */ |
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159 static inline Foundation InclinedFoundation(Axis axis) |
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160 { |
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161 return (axis == AXIS_X ? FOUNDATION_INCLINED_X : FOUNDATION_INCLINED_Y); |
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162 } |
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163 |
43 #endif /* SLOPE_H */ |
164 #endif /* SLOPE_H */ |