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Boids - A Shoes Application
<div style="overflow:auto;border:solid 1px #ccc;background:#000;color:#F8F8F8"> <div class="section"> <pre style="float:left;margin:0 10px;border-right:0;color:#666;">1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197</pre> <pre class="sunburst"><span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Boids - A Shoes Application</span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span></span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Author : Wally Glutton - http://stungeye.com</span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Summary : A hungry swarm indeed!</span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span></span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Notes : My home-rolled Vector class appears to be quicker than the matrix library Vectors.</span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Boid Algo : http://www.vergenet.net/~conrad/boids/pseudocode.html</span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span></span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Required : You must have Shoes installed to view the boids.</span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Get Shoes : http://code.whytheluckystiff.net/shoes/</span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Learn Shoes : http://hackety.org/press/nks.html</span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span></span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Code License : http://creativecommons.org/licenses/by-sa/2.5/ca/</span> srand <span style="color:#3E87E3;">NUM_BOIDS</span> <span style="color:#E28964;">=</span> <span style="color:#3387CC;">30</span> <span style="color:#3E87E3;">NUM_FOODSTUFF</span> <span style="color:#E28964;">=</span> <span style="color:#3387CC;">6</span> boids <span style="color:#E28964;">=</span> [] foodstuff <span style="color:#E28964;">=</span> [] <span style="color:#9B859D;">Shoes</span>.<span style="color:#89BDFF;">app</span> <span style="color:#E28964;">do</span> stroke <span style="color:#89BDFF;">rgb</span>(<span style="color:#3387CC;">0x30</span>, <span style="color:#3387CC;">0x30</span>, <span style="color:#3387CC;">0x05</span>, <span style="color:#3387CC;">0.5</span>) app <span style="color:#E28964;">=</span> <span style="color:#3E87E3;">self</span> <span style="color:#3E87E3;">NUM_BOIDS</span>.<span style="color:#89BDFF;">times</span> { |<span style="color:#3E87E3;">i</span>| boids[i] <span style="color:#E28964;">=</span> <span style="color:#9B859D;">Boid</span>.<span style="color:#89BDFF;">new</span> rand <span style="color:#E28964;">*</span> <span style="color:#3E87E3;">self</span>.<span style="color:#89BDFF;">width</span>, rand <span style="color:#E28964;">*</span> <span style="color:#3E87E3;">self</span>.<span style="color:#89BDFF;">height</span>, <span style="color:#89BDFF;">random</span>(<span style="color:#E28964;">-</span><span style="color:#3387CC;">5</span>, <span style="color:#3387CC;">5</span>), <span style="color:#89BDFF;">random</span>(<span style="color:#E28964;">-</span><span style="color:#3387CC;">5</span>, <span style="color:#3387CC;">5</span>) } <span style="color:#3E87E3;">NUM_FOODSTUFF</span>.<span style="color:#89BDFF;">times</span> { |<span style="color:#3E87E3;">i</span>| foodstuff[i] <span style="color:#E28964;">=</span> <span style="color:#9B859D;">Food</span>.<span style="color:#89BDFF;">new</span> app} <span style="color:#89BDFF;">animate</span>(<span style="color:#3387CC;">24</span>) <span style="color:#E28964;">do</span> clear <span style="color:#E28964;">do</span> boids.<span style="color:#89BDFF;">each</span> <span style="color:#E28964;">do </span>|<span style="color:#3E87E3;">boid</span>| boid.<span style="color:#89BDFF;">calculate_avoidance_delta</span> boids <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Avoid other boids</span> boid.<span style="color:#89BDFF;">calculate_attraction_delta</span> boids <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Gravitate towards the centre-of-mass of nearby boids</span> boid.<span style="color:#89BDFF;">calculate_allignment_delta</span> boids <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Allign velocity with nearby boids</span> boid.<span style="color:#89BDFF;">calculate_hunting_delta</span> foodstuff <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Be on the lookout for food</span> boid.<span style="color:#89BDFF;">calculate_stay_visible_delta</span> <span style="color:#3E87E3;">self</span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Don't fly too far from home</span> boid.<span style="color:#89BDFF;">apply_deltas</span> boid.<span style="color:#89BDFF;">limit_speed</span> boid.<span style="color:#89BDFF;">move</span> boid.<span style="color:#89BDFF;">draw</span> <span style="color:#3E87E3;">self</span>, app foodstuff.<span style="color:#89BDFF;">each</span> <span style="color:#E28964;">do </span>|<span style="color:#3E87E3;">food</span>| food.<span style="color:#89BDFF;">eaten?</span> boid <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> foodstuff.<span style="color:#89BDFF;">each</span> <span style="color:#E28964;">do </span>|<span style="color:#3E87E3;">food</span>| food.<span style="color:#89BDFF;">draw</span> <span style="color:#3E87E3;">self</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">class</span> <span style="text-decoration:underline;">Food</span> <span style="color:#3E87E3;">RADIUS</span> <span style="color:#E28964;">=</span> <span style="color:#3387CC;">30</span> <span style="color:#E28964;">attr_reader</span> <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>position</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">initialize</span> app <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>app</span> <span style="color:#E28964;">=</span> app spawn <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">spawn</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>size</span> <span style="color:#E28964;">=</span> <span style="color:#3E87E3;">RADIUS</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span> <span style="color:#E28964;">=</span> <span style="color:#9B859D;">VectorK</span>.<span style="color:#89BDFF;">new</span> rand <span style="color:#E28964;">*</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>app</span>.<span style="color:#89BDFF;">width</span>, rand <span style="color:#E28964;">*</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>app</span>.<span style="color:#89BDFF;">height</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">eaten?</span> boid <span style="color:#E28964;">if</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span>.<span style="color:#89BDFF;">nearby?</span> <span style="color:#3E87E3;">RADIUS</span>, boid.<span style="color:#89BDFF;">position</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>size</span> <span style="color:#E28964;">-=</span> <span style="color:#3387CC;">1</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">if</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>size</span> <span style="color:#E28964;"><</span> <span style="color:#3387CC;">0</span> spawn <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">draw</span> slot <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>app</span>.<span style="color:#89BDFF;">fill</span> <span style="color:#89BDFF;">rgb</span>(<span style="color:#3387CC;">0xFF</span>, <span style="color:#3387CC;">0x30</span>, <span style="color:#3387CC;">0xFF</span>, <span style="color:#3387CC;">0.4</span>) slot.<span style="color:#89BDFF;">oval</span> <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>left</span> => <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span>.<span style="color:#89BDFF;">x</span>, <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>top</span> => <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span>.<span style="color:#89BDFF;">y</span>, <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>radius</span> => <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>size</span>, <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>center</span> => <span style="color:#3387CC;">true</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">class</span> <span style="text-decoration:underline;">Boid</span> <span style="color:#3E87E3;">RADIUS</span> <span style="color:#E28964;">=</span> <span style="color:#3387CC;">20</span> <span style="color:#3E87E3;">MAX_SPEED</span> <span style="color:#E28964;">=</span> <span style="color:#3387CC;">25</span> <span style="color:#3E87E3;">AVOID_RADIUS</span> <span style="color:#E28964;">=</span> <span style="color:#3E87E3;">RADIUS</span><span style="color:#E28964;">*</span><span style="color:#3387CC;">3</span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Avoid other boids within this radius</span> <span style="color:#3E87E3;">AVOID_DAMPER</span> <span style="color:#E28964;">=</span> <span style="color:#3387CC;">100</span> <span style="color:#3E87E3;">ATTRACTION_RADIUS</span> <span style="color:#E28964;">=</span> <span style="color:#3E87E3;">RADIUS</span><span style="color:#E28964;">*</span><span style="color:#3387CC;">8</span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Gravitate to the centre of mass of boids within this radius</span> <span style="color:#3E87E3;">ATTRACTION_DAMPER</span> <span style="color:#E28964;">=</span> <span style="color:#3387CC;">30</span> <span style="color:#3E87E3;">ALLIGNMENT_RADIUS</span> <span style="color:#E28964;">=</span> <span style="color:#3E87E3;">RADIUS</span><span style="color:#E28964;">*</span><span style="color:#3387CC;">3</span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Allign velocity with boids within this radius</span> <span style="color:#3E87E3;">ALLIGNMENT_DAMPER</span> <span style="color:#E28964;">=</span> <span style="color:#3387CC;">30</span> <span style="color:#3E87E3;">HUNTING_RADIUS</span> <span style="color:#E28964;">=</span> <span style="color:#3E87E3;">RADIUS</span><span style="color:#E28964;">*</span><span style="color:#3387CC;">5</span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Locate food within this radius</span> <span style="color:#3E87E3;">HUNTUNG_DAMPER</span> <span style="color:#E28964;">=</span> <span style="color:#3387CC;">10</span> <span style="color:#3E87E3;">STAY_VISIBLE_DAMPER</span> <span style="color:#E28964;">=</span> <span style="color:#3387CC;">300</span> <span style="color:#E28964;">attr_reader</span> <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>velocity</span>, <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>position</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">initialize</span> x, y, vx, vy <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity</span> <span style="color:#E28964;">=</span> <span style="color:#9B859D;">VectorK</span>.<span style="color:#89BDFF;">new</span> vx, vy <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span> <span style="color:#E28964;">=</span> <span style="color:#9B859D;">VectorK</span>.<span style="color:#89BDFF;">new</span> x, y <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity_delta</span> <span style="color:#E28964;">=</span> <span style="color:#9B859D;">VectorK</span>.<span style="color:#89BDFF;">new</span> <span style="color:#3387CC;">0</span>, <span style="color:#3387CC;">0</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">calculate_avoidance_delta</span> boids boids.<span style="color:#89BDFF;">each</span> <span style="color:#E28964;">do </span>|<span style="color:#3E87E3;">other</span>| <span style="color:#E28964;">if</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span>.<span style="color:#89BDFF;">nearby?</span> <span style="color:#3E87E3;">AVOID_RADIUS</span>, other.<span style="color:#89BDFF;">position</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity_delta</span> <span style="color:#E28964;">+=</span> (<span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span> <span style="color:#E28964;">-</span> other.<span style="color:#89BDFF;">position</span>) <span style="color:#E28964;">/</span> <span style="color:#3E87E3;">AVOID_DAMPER</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">calculate_attraction_delta</span> boids average_position <span style="color:#E28964;">=</span> <span style="color:#9B859D;">VectorK</span>.<span style="color:#89BDFF;">new</span> <span style="color:#3387CC;">0</span>, <span style="color:#3387CC;">0</span> visible_boids <span style="color:#E28964;">=</span> <span style="color:#3387CC;">0</span> boids.<span style="color:#89BDFF;">each</span> <span style="color:#E28964;">do </span>|<span style="color:#3E87E3;">other</span>| <span style="color:#E28964;">if</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span>.<span style="color:#89BDFF;">nearby?</span> <span style="color:#3E87E3;">ATTRACTION_RADIUS</span>, other.<span style="color:#89BDFF;">position</span> average_position <span style="color:#E28964;">+=</span> other.<span style="color:#89BDFF;">position</span> visible_boids <span style="color:#E28964;">+=</span> <span style="color:#3387CC;">1</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> average_position <span style="color:#E28964;">/=</span> visible_boids <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity_delta</span> <span style="color:#E28964;">+=</span> (average_position <span style="color:#E28964;">-</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span>) <span style="color:#E28964;">/</span> <span style="color:#3E87E3;">ATTRACTION_DAMPER</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">calculate_allignment_delta</span> boids allignment_delta <span style="color:#E28964;">=</span> <span style="color:#9B859D;">VectorK</span>.<span style="color:#89BDFF;">new</span> <span style="color:#3387CC;">0</span>, <span style="color:#3387CC;">0</span> visible_boids <span style="color:#E28964;">=</span> <span style="color:#3387CC;">0</span> boids.<span style="color:#89BDFF;">each</span> <span style="color:#E28964;">do </span>|<span style="color:#3E87E3;">other</span>| <span style="color:#E28964;">if</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span>.<span style="color:#89BDFF;">nearby?</span> <span style="color:#3E87E3;">ALLIGNMENT_RADIUS</span>, other.<span style="color:#89BDFF;">position</span> allignment_delta <span style="color:#E28964;">+=</span> other.<span style="color:#89BDFF;">velocity</span> visible_boids <span style="color:#E28964;">+=</span> <span style="color:#3387CC;">1</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> allignment_delta <span style="color:#E28964;">/=</span> visible_boids <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity_delta</span> <span style="color:#E28964;">+=</span> allignment_delta <span style="color:#E28964;">/</span> <span style="color:#3E87E3;">ALLIGNMENT_DAMPER</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">calculate_hunting_delta</span> foodstuff foodstuff.<span style="color:#89BDFF;">each</span> <span style="color:#E28964;">do </span>|<span style="color:#3E87E3;">food</span>| <span style="color:#E28964;">if</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span>.<span style="color:#89BDFF;">nearby?</span> <span style="color:#3E87E3;">HUNTING_RADIUS</span>, food.<span style="color:#89BDFF;">position</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity_delta</span> <span style="color:#E28964;">+=</span> (food.<span style="color:#89BDFF;">position</span> <span style="color:#E28964;">-</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span>) <span style="color:#E28964;">/</span> <span style="color:#3E87E3;">HUNTUNG_DAMPER</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">calculate_stay_visible_delta</span> slot mid_x <span style="color:#E28964;">=</span> slot.<span style="color:#89BDFF;">width</span> <span style="color:#E28964;">/</span> <span style="color:#3387CC;">2</span> mid_y <span style="color:#E28964;">=</span> slot.<span style="color:#89BDFF;">height</span> <span style="color:#E28964;">/</span> <span style="color:#3387CC;">2</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity_delta</span> <span style="color:#E28964;">-=</span> (<span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span> <span style="color:#E28964;">-</span> <span style="color:#9B859D;">VectorK</span>.<span style="color:#89BDFF;">new</span>(mid_x, mid_y)) <span style="color:#E28964;">/</span> <span style="color:#3E87E3;">STAY_VISIBLE_DAMPER</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">apply_deltas</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity</span> <span style="color:#E28964;">+=</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity_delta</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity_delta</span> <span style="color:#E28964;">=</span> <span style="color:#9B859D;">VectorK</span>.<span style="color:#89BDFF;">new</span> <span style="color:#3387CC;">0</span>, <span style="color:#3387CC;">0</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">limit_speed</span> <span style="color:#E28964;">if</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity</span>.<span style="color:#89BDFF;">r</span> <span style="color:#E28964;">></span> <span style="color:#3E87E3;">MAX_SPEED</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity</span> <span style="color:#E28964;">/=</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity</span>.<span style="color:#89BDFF;">r</span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Create a unit vector</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity</span> <span style="color:#E28964;">*=</span> <span style="color:#3E87E3;">MAX_SPEED</span> <span style="color:#AEAEAE;font-style:italic;"><span style="color:#AEAEAE;font-style:italic;">#</span> Scale to max speed</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">move</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span> <span style="color:#E28964;">+=</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">draw</span> slot, app app.<span style="color:#89BDFF;">fill</span> <span style="color:#89BDFF;">rgb</span>(<span style="color:#3387CC;">0x30</span>, <span style="color:#3387CC;">0xFF</span>, <span style="color:#3387CC;">0xFF</span>, <span style="color:#3387CC;">0.5</span>) slot.<span style="color:#89BDFF;">oval</span> <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>left</span> => <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span>.<span style="color:#89BDFF;">x</span>, <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>top</span> => <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span>.<span style="color:#89BDFF;">y</span>, <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>radius</span> => <span style="color:#3E87E3;">RADIUS</span>, <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>center</span> => <span style="color:#3387CC;">true</span> slot.<span style="color:#89BDFF;">line</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span>.<span style="color:#89BDFF;">x</span>, <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span>.<span style="color:#89BDFF;">y</span>, (<span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span>.<span style="color:#89BDFF;">x</span> <span style="color:#E28964;">+</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity</span>.<span style="color:#89BDFF;">x</span>), (<span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>position</span>.<span style="color:#89BDFF;">y</span> <span style="color:#E28964;">+</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>velocity</span>.<span style="color:#89BDFF;">y</span>) <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">class</span> <span style="text-decoration:underline;">VectorK</span> <span style="color:#E28964;">attr_reader</span> <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>x</span>, <span style="color:#3387CC;"><span style="color:#3387CC;">:</span>y</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">initialize</span> x, y <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>x</span> <span style="color:#E28964;">=</span> x <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>y</span> <span style="color:#E28964;">=</span> y <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">nearby?</span> threshold, a <span style="color:#E28964;">return</span> <span style="color:#3387CC;">false</span> <span style="color:#E28964;">if</span> a <span style="color:#E28964;">===</span> <span style="color:#3E87E3;">self</span> (distance a) <span style="color:#E28964;"><</span> threshold <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">distance</span> a <span style="color:#9B859D;">Math</span>.<span style="color:#89BDFF;">sqrt</span>((<span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>x</span> <span style="color:#E28964;">-</span> a.<span style="color:#89BDFF;">x</span>)<span style="color:#E28964;">**</span><span style="color:#3387CC;">2</span> <span style="color:#E28964;">+</span> (<span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>y</span> <span style="color:#E28964;">-</span> a.<span style="color:#89BDFF;">y</span>)<span style="color:#E28964;">**</span><span style="color:#3387CC;">2</span>) <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">/</span> a <span style="color:#E28964;">if</span> (a <span style="color:#E28964;">!=</span> <span style="color:#3387CC;">0</span>) <span style="color:#9B859D;">VectorK</span>.<span style="color:#89BDFF;">new</span>(<span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>x</span> <span style="color:#E28964;">/</span> a, <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>y</span> <span style="color:#E28964;">/</span> a) <span style="color:#E28964;">else</span> <span style="color:#3E87E3;">self</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">+</span> a <span style="color:#9B859D;">VectorK</span>.<span style="color:#89BDFF;">new</span>(<span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>x</span> <span style="color:#E28964;">+</span> a.<span style="color:#89BDFF;">x</span>, <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>y</span> <span style="color:#E28964;">+</span> a.<span style="color:#89BDFF;">y</span>) <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">-</span> a <span style="color:#9B859D;">VectorK</span>.<span style="color:#89BDFF;">new</span>(<span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>x</span> <span style="color:#E28964;">-</span> a.<span style="color:#89BDFF;">x</span>, <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>y</span> <span style="color:#E28964;">-</span> a.<span style="color:#89BDFF;">y</span>) <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">*</span> a <span style="color:#9B859D;">VectorK</span>.<span style="color:#89BDFF;">new</span>(<span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>x</span> <span style="color:#E28964;">*</span> a, <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>y</span> <span style="color:#E28964;">*</span> a) <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">r</span> <span style="color:#9B859D;">Math</span>.<span style="color:#89BDFF;">sqrt</span>(<span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>x</span> <span style="color:#E28964;">*</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>x</span> <span style="color:#E28964;">+</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>y</span> <span style="color:#E28964;">*</span> <span style="color:#3E87E3;"><span style="color:#3E87E3;">@</span>y</span>) <span style="color:#E28964;">end</span> <span style="color:#E28964;">end</span> <span style="color:#E28964;">def</span> <span style="color:#89BDFF;">random</span> min, max choice <span style="color:#E28964;">=</span> (max <span style="color:#E28964;">-</span> min <span style="color:#E28964;">></span> <span style="color:#3387CC;">0</span>) <span style="color:#E28964;">?</span> (rand max <span style="color:#E28964;">-</span> min) <span style="color:#E28964;">+</span> min : <span style="color:#3387CC;">0</span>; <span style="color:#E28964;">end</span> </pre> </div> </div> <a href="http://refactormycode.com/codes/248-boids-a-shoes-application" style="color:#fff" title="As seen on RefactorMyCode.com"><img alt="Small_logo" src="http://refactormycode.com/images/small_logo.gif" style="border:0" /></a>