Mercurial > projects > openmelee
annotate ai/steer.d @ 18:7f74e064dad5
refactored code
| author | zzzzrrr <mason.green@gmail.com> |
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| date | Wed, 25 Mar 2009 11:28:25 -0400 |
| parents | steer.d@8e6a9e390cba |
| children | 08ddf9e71b88 |
| rev | line source |
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1 /* |
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2 * Copyright (c) 2009, Mason Green (zzzzrrr) |
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3 * http://www.dsource.org/projects/openmelee |
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4 * Based on OpenSteer, Copyright (c) 2002-2003, Sony Computer Entertainment America |
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5 * Original author: Craig Reynolds |
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6 * |
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7 * All rights reserved. |
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8 * |
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9 * Redistribution and use in source and binary forms, with or without modification, |
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10 * are permitted provided that the following conditions are met: |
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11 * |
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12 * * Redistributions of source code must retain the above copyright notice, |
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13 * this list of conditions and the following disclaimer. |
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14 * * Redistributions in binary form must reproduce the above copyright notice, |
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15 * this list of conditions and the following disclaimer in the documentation |
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16 * and/or other materials provided with the distribution. |
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17 * * Neither the name of the polygonal nor the names of its contributors may be |
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18 * used to endorse or promote products derived from this software without specific |
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19 * prior written permission. |
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20 * |
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21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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22 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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24 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
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25 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
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26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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27 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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28 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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29 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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30 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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31 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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32 */ |
| 18 | 33 module openmelee.ai.steer; |
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34 |
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35 import blaze.common.bzMath: bzDot, bzClamp, bzVec2; |
| 15 | 36 import blaze.dynamics.bzBody: bzBody; |
| 37 | |
| 18 | 38 import openmelee.ships.ship : Ship, State; |
| 39 import openmelee.ai.utilities; | |
| 0 | 40 |
| 9 | 41 class Steer |
| 42 { | |
| 43 // Constructor: initializes state | |
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44 this (Ship ship) |
| 0 | 45 { |
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46 m_ship = ship; |
| 15 | 47 } |
| 48 | |
| 49 struct PathIntersection | |
| 50 { | |
| 51 bool intersect; | |
| 52 float distance; | |
| 53 bzVec2 surfacePoint; | |
| 54 bzVec2 surfaceNormal; | |
| 55 bzBody obstacle; | |
| 9 | 56 } |
| 0 | 57 |
| 9 | 58 // reset state |
| 59 void reset () { | |
| 60 // initial state of wander behavior | |
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61 m_wanderSide = 0; |
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62 m_wanderUp = 0; |
| 9 | 63 } |
| 64 | |
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65 void update() { |
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66 m_position = m_ship.state.position; |
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67 m_velocity = m_ship.state.velocity; |
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68 m_speed = m_ship.state.speed; |
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69 m_maxForce = m_ship.state.maxForce; |
| 12 | 70 m_forward = m_ship.state.forward; |
| 9 | 71 } |
| 0 | 72 |
| 9 | 73 // -------------------------------------------------- steering behaviors |
| 0 | 74 |
| 9 | 75 bzVec2 steerForWander (float dt) { |
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76 // random walk m_wanderSide and m_wanderUp between -1 and +1 |
| 9 | 77 float speed = 12 * dt; // maybe this (12) should be an argument? |
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78 m_wanderSide = scalarRandomWalk (m_wanderSide, speed, -1, +1); |
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79 m_wanderUp = scalarRandomWalk (m_wanderUp, speed, -1, +1); |
| 0 | 80 |
| 9 | 81 // return a pure lateral steering vector: (+/-Side) + (+/-Up) |
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82 return (m_side * m_wanderSide) + (m_up * m_wanderUp); |
| 9 | 83 } |
| 0 | 84 |
| 9 | 85 // Seek behavior |
| 86 bzVec2 steerForSeek (bzVec2 target) { | |
| 87 bzVec2 desiredVelocity = target - m_position; | |
| 88 return desiredVelocity - m_velocity; | |
| 89 } | |
| 0 | 90 |
| 9 | 91 // Flee behavior |
| 92 bzVec2 steerForFlee (bzVec2 target) { | |
| 93 bzVec2 desiredVelocity = m_position - target; | |
| 94 return desiredVelocity - m_velocity; | |
| 95 } | |
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96 |
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97 /* |
| 9 | 98 // xxx proposed, experimental new seek/flee [cwr 9-16-02] |
| 99 bzVec2 xxxsteerForFlee (bzVec2 target) { | |
| 100 bzVec2 offset = m_position - target; | |
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101 bzVec2 desiredVelocity = bzClamp(offset.truncateLength (maxSpeed ()); |
| 9 | 102 return desiredVelocity - m_velocity; |
| 103 } | |
| 0 | 104 |
| 9 | 105 bzVec2 xxxsteerForSeek (bzVec2 target) { |
| 106 // bzVec2 offset = target - position; | |
| 107 bzVec2 offset = target - m_position; | |
| 108 bzVec2 desiredVelocity = offset.truncateLength (maxSpeed ()); //xxxnew | |
| 109 return desiredVelocity - m_velocity; | |
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110 } |
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111 */ |
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112 |
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113 /* |
| 9 | 114 // ------------------------------------------------------------------------ |
| 115 // Obstacle Avoidance behavior | |
| 116 // | |
| 117 // Returns a steering force to avoid a given obstacle. The purely | |
| 118 // lateral steering force will turn our vehicle towards a silhouette edge | |
| 119 // of the obstacle. Avoidance is required when (1) the obstacle | |
| 120 // intersects the vehicle's current path, (2) it is in front of the | |
| 121 // vehicle, and (3) is within minTimeToCollision seconds of travel at the | |
| 122 // vehicle's current velocity. Returns a zero vector value (bzVec2::zero) | |
| 123 // when no avoidance is required. | |
| 124 bzVec2 steerToAvoidObstacle (float minTimeToCollision, Obstacle obstacle) { | |
| 0 | 125 |
| 9 | 126 bzVec2 avoidance = obstacle.steerToAvoid (this, minTimeToCollision); |
| 127 return avoidance; | |
| 128 } | |
| 129 | |
| 15 | 130 // avoids all obstacles in an ObstacleGroup |
| 131 */ | |
| 132 | |
| 133 bzVec2 steerToAvoidObstacles (float minTimeToCollision, bzBody obstacles) { | |
| 0 | 134 |
| 9 | 135 bzVec2 avoidance; |
| 136 PathIntersection nearest, next; | |
| 15 | 137 float minDistanceToCollision = minTimeToCollision * m_speed; |
| 0 | 138 |
| 9 | 139 next.intersect = false; |
| 140 nearest.intersect = false; | |
| 0 | 141 |
| 9 | 142 // test all obstacles for intersection with my forward axis, |
| 143 // select the one whose point of intersection is nearest | |
| 15 | 144 for (bzBody o; o; o = o.next) { |
| 145 // This code which presumes the obstacle is spherical | |
| 146 //findNextIntersectionWithSphere (o, next); | |
| 0 | 147 |
| 15 | 148 if (!nearest.intersect || (next.intersect && next.distance < nearest.distance)) { |
| 149 nearest = next; | |
| 150 } | |
| 9 | 151 } |
| 0 | 152 |
| 9 | 153 // when a nearest intersection was found |
| 15 | 154 if (nearest.intersect && (nearest.distance < minDistanceToCollision)) { |
| 9 | 155 // compute avoidance steering force: take offset from obstacle to me, |
| 156 // take the component of that which is lateral (perpendicular to my | |
| 157 // forward direction), set length to maxForce, add a bit of forward | |
| 158 // component (in capture the flag, we never want to slow down) | |
| 15 | 159 bzVec2 offset = m_position - nearest.obstacle.position; |
| 160 //avoidance = Vector3Helpers.PerpendicularComponent(offset, this.Forward); | |
| 161 avoidance.normalize; | |
| 162 avoidance *= m_maxForce; | |
| 163 avoidance += m_forward * m_maxForce * 0.75f; | |
| 0 | 164 } |
| 165 | |
| 9 | 166 return avoidance; |
| 167 } | |
| 15 | 168 |
| 169 /* | |
| 9 | 170 // ------------------------------------------------------------------------ |
| 171 // Unaligned collision avoidance behavior: avoid colliding with other | |
| 172 // nearby vehicles moving in unconstrained directions. Determine which | |
| 173 // (if any) other other vehicle we would collide with first, then steers | |
| 174 // to avoid the site of that potential collision. Returns a steering | |
| 175 // force vector, which is zero length if there is no impending collision. | |
| 176 | |
| 177 bzVec2 steerToAvoidNeighbors (float minTimeToCollision, AVGroup others) { | |
| 0 | 178 |
| 9 | 179 // first priority is to prevent immediate interpenetration |
| 180 bzVec2 separation = steerToAvoidCloseNeighbors (0, others); | |
| 181 if (separation != bzVec2::zero) return separation; | |
| 0 | 182 |
| 9 | 183 // otherwise, go on to consider potential future collisions |
| 184 float steer = 0; | |
| 15 | 185 Ship threat; |
| 9 | 186 |
| 187 // Time (in seconds) until the most immediate collision threat found | |
| 188 // so far. Initial value is a threshold: don't look more than this | |
| 189 // many frames into the future. | |
| 190 float minTime = minTimeToCollision; | |
| 0 | 191 |
| 9 | 192 // xxx solely for annotation |
| 193 bzVec2 xxxThreatPositionAtNearestApproach; | |
| 194 bzVec2 xxxOurPositionAtNearestApproach; | |
| 0 | 195 |
| 9 | 196 // for each of the other vehicles, determine which (if any) |
| 197 // pose the most immediate threat of collision. | |
| 198 for (AVIterator i = others.begin(); i != others.end(); i++) | |
| 199 { | |
| 15 | 200 Ship other = i; |
| 201 if (other !is this) | |
| 0 | 202 { |
| 9 | 203 // avoid when future positions are this close (or less) |
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204 float collisionDangerThreshold = radius * 2; |
| 9 | 205 |
| 206 // predicted time until nearest approach of "this" and "other" | |
| 207 float time = predictNearestApproachTime (other); | |
| 0 | 208 |
| 9 | 209 // If the time is in the future, sooner than any other |
| 210 // threatened collision... | |
| 211 if ((time >= 0) (time < minTime)) | |
| 212 { | |
| 213 // if the two will be close enough to collide, | |
| 214 // make a note of it | |
| 215 if (computeNearestApproachPositions (other, time) | |
| 216 < collisionDangerThreshold) | |
| 0 | 217 { |
| 9 | 218 minTime = time; |
| 219 threat = other; | |
| 220 xxxThreatPositionAtNearestApproach | |
| 221 = hisPositionAtNearestApproach; | |
| 222 xxxOurPositionAtNearestApproach | |
| 223 = ourPositionAtNearestApproach; | |
| 0 | 224 } |
| 225 } | |
| 226 } | |
| 9 | 227 } |
| 0 | 228 |
| 9 | 229 // if a potential collision was found, compute steering to avoid |
| 230 if (threat) | |
| 231 { | |
| 232 // parallel: +1, perpendicular: 0, anti-parallel: -1 | |
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233 float parallelness = m_forward.dot(threat.forward); |
| 9 | 234 float angle = 0.707f; |
| 235 | |
| 236 if (parallelness < -angle) | |
| 0 | 237 { |
| 9 | 238 // anti-parallel "head on" paths: |
| 239 // steer away from future threat position | |
| 240 bzVec2 offset = xxxThreatPositionAtNearestApproach - m_position; | |
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241 float sideDot = offset.dot(m_side()); |
| 9 | 242 steer = (sideDot > 0) ? -1.0f : 1.0f; |
| 243 } | |
| 244 else | |
| 245 { | |
| 246 if (parallelness > angle) | |
| 0 | 247 { |
| 9 | 248 // parallel paths: steer away from threat |
| 249 bzVec2 offset = threat.position - m_position; | |
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250 float sideDot = bzDot(offset, m_side); |
| 0 | 251 steer = (sideDot > 0) ? -1.0f : 1.0f; |
| 252 } | |
| 253 else | |
| 254 { | |
| 9 | 255 // perpendicular paths: steer behind threat |
| 256 // (only the slower of the two does this) | |
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257 if (threat.speed() <= speed) |
| 0 | 258 { |
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259 float sideDot = bzDot(m_side, threat.velocity); |
| 0 | 260 steer = (sideDot > 0) ? -1.0f : 1.0f; |
| 261 } | |
| 262 } | |
| 263 } | |
| 264 } | |
| 265 | |
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266 return m_side() * steer; |
| 9 | 267 } |
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268 */ |
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269 |
| 9 | 270 // Given two vehicles, based on their current positions and velocities, |
| 271 // determine the time until nearest approach | |
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272 float predictNearestApproachTime (State other) { |
| 9 | 273 |
| 274 // imagine we are at the origin with no velocity, | |
| 275 // compute the relative velocity of the other vehicle | |
| 276 bzVec2 myVelocity = m_velocity; | |
| 277 bzVec2 otherVelocity = other.velocity; | |
| 278 bzVec2 relVelocity = otherVelocity - myVelocity; | |
| 279 float relSpeed = relVelocity.length; | |
| 280 | |
| 281 // for parallel paths, the vehicles will always be at the same distance, | |
| 282 // so return 0 (aka "now") since "there is no time like the present" | |
| 283 if (relSpeed == 0) return 0; | |
| 284 | |
| 285 // Now consider the path of the other vehicle in this relative | |
| 286 // space, a line defined by the relative position and velocity. | |
| 287 // The distance from the origin (our vehicle) to that line is | |
| 288 // the nearest approach. | |
| 289 | |
| 290 // Take the unit tangent along the other vehicle's path | |
| 291 bzVec2 relTangent = relVelocity / relSpeed; | |
| 292 | |
| 293 // find distance from its path to origin (compute offset from | |
| 294 // other to us, find length of projection onto path) | |
| 295 bzVec2 relPosition = m_position - other.position; | |
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296 float projection = bzDot(relTangent, relPosition); |
| 9 | 297 |
| 298 return projection / relSpeed; | |
| 299 } | |
| 0 | 300 |
| 9 | 301 // Given the time until nearest approach (predictNearestApproachTime) |
| 302 // determine position of each vehicle at that time, and the distance | |
| 303 // between them | |
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304 float computeNearestApproachPositions (State other, float time) { |
| 0 | 305 |
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306 bzVec2 myTravel = m_forward * m_speed * time; |
| 9 | 307 bzVec2 otherTravel = other.forward * other.speed * time; |
| 308 | |
| 309 bzVec2 myFinal = m_position + myTravel; | |
| 310 bzVec2 otherFinal = other.position + otherTravel; | |
| 0 | 311 |
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312 return (myFinal - otherFinal).length; |
| 9 | 313 } |
| 314 | |
| 315 // ------------------------------------------------------------------------ | |
| 316 // pursuit of another vehicle ( version with ceiling on prediction time) | |
| 317 | |
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318 bzVec2 steerForPursuit (State quarry) { |
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319 return steerForPursuit (quarry, float.max); |
| 9 | 320 } |
| 321 | |
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322 bzVec2 steerForPursuit (State quarry, float maxPredictionTime) { |
| 0 | 323 |
| 9 | 324 // offset from this to quarry, that distance, unit vector toward quarry |
| 325 bzVec2 offset = quarry.position - m_position; | |
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326 float distance = offset.length; |
| 9 | 327 bzVec2 unitOffset = offset / distance; |
| 328 | |
| 329 // how parallel are the paths of "this" and the quarry | |
| 330 // (1 means parallel, 0 is pependicular, -1 is anti-parallel) | |
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331 float parallelness = bzDot(m_forward , quarry.forward); |
| 9 | 332 |
| 333 // how "forward" is the direction to the quarry | |
| 334 // (1 means dead ahead, 0 is directly to the side, -1 is straight back) | |
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335 float forwardness = bzDot(m_forward , unitOffset); |
| 0 | 336 |
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337 float directTravelTime = distance / m_speed; |
| 9 | 338 int f = intervalComparison (forwardness, -0.707f, 0.707f); |
| 339 int p = intervalComparison (parallelness, -0.707f, 0.707f); | |
| 340 | |
| 341 float timeFactor = 0; // to be filled in below | |
| 0 | 342 |
| 9 | 343 // Break the pursuit into nine cases, the cross product of the |
| 344 // quarry being [ahead, aside, or behind] us and heading | |
| 345 // [parallel, perpendicular, or anti-parallel] to us. | |
| 346 switch (f) | |
| 347 { | |
| 348 case +1: | |
| 349 switch (p) | |
| 0 | 350 { |
| 9 | 351 case +1: // ahead, parallel |
| 352 timeFactor = 4; | |
| 0 | 353 break; |
| 9 | 354 case 0: // ahead, perpendicular |
| 355 timeFactor = 1.8f; | |
| 0 | 356 break; |
| 9 | 357 case -1: // ahead, anti-parallel |
| 358 timeFactor = 0.85f; | |
| 0 | 359 break; |
| 360 } | |
| 9 | 361 break; |
| 362 case 0: | |
| 363 switch (p) | |
| 364 { | |
| 365 case +1: // aside, parallel | |
| 366 timeFactor = 1; | |
| 367 break; | |
| 368 case 0: // aside, perpendicular | |
| 369 timeFactor = 0.8f; | |
| 370 break; | |
| 371 case -1: // aside, anti-parallel | |
| 372 timeFactor = 4; | |
| 373 break; | |
| 374 } | |
| 375 break; | |
| 376 case -1: | |
| 377 switch (p) | |
| 378 { | |
| 379 case +1: // behind, parallel | |
| 380 timeFactor = 0.5f; | |
| 381 break; | |
| 382 case 0: // behind, perpendicular | |
| 383 timeFactor = 2; | |
| 384 break; | |
| 385 case -1: // behind, anti-parallel | |
| 386 timeFactor = 2; | |
| 387 break; | |
| 388 } | |
| 389 break; | |
| 390 } | |
| 0 | 391 |
| 9 | 392 // estimated time until intercept of quarry |
| 393 float et = directTravelTime * timeFactor; | |
| 394 | |
| 395 // xxx experiment, if kept, this limit should be an argument | |
| 396 float etl = (et > maxPredictionTime) ? maxPredictionTime : et; | |
| 397 | |
| 398 // estimated position of quarry at intercept | |
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399 bzVec2 target = quarry.predictFuturePosition(etl); |
| 0 | 400 |
| 12 | 401 return target; //steerForSeek (target); |
| 9 | 402 } |
| 403 | |
| 404 // ------------------------------------------------------------------------ | |
| 405 // evasion of another vehicle | |
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406 bzVec2 steerForEvasion (State menace, float maxPredictionTime) { |
| 0 | 407 |
| 9 | 408 // offset from this to menace, that distance, unit vector toward menace |
| 409 bzVec2 offset = menace.position - m_position; | |
| 410 float distance = offset.length; | |
| 0 | 411 |
| 9 | 412 float roughTime = distance / menace.speed; |
| 413 float predictionTime = ((roughTime > maxPredictionTime) ? maxPredictionTime : roughTime); | |
| 414 bzVec2 target = menace.predictFuturePosition (predictionTime); | |
| 415 | |
| 416 return steerForFlee (target); | |
| 417 } | |
| 0 | 418 |
| 419 | |
| 9 | 420 // ------------------------------------------------------------------------ |
| 421 // tries to maintain a given speed, returns a maxForce-clipped steering | |
| 422 // force along the forward/backward axis | |
| 423 bzVec2 steerForTargetSpeed (float targetSpeed) { | |
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424 float mf = m_maxForce; |
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425 float speedError = targetSpeed - m_speed; |
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426 return m_forward * bzClamp(speedError, -mf, +mf); |
| 9 | 427 } |
| 0 | 428 |
| 429 | |
| 9 | 430 // ----------------------------------------------------------- utilities |
| 431 bool isAhead (bzVec2 target) {return isAhead (target, 0.707f);}; | |
| 432 bool isAside (bzVec2 target) {return isAside (target, 0.707f);}; | |
| 433 bool isBehind (bzVec2 target) {return isBehind (target, -0.707f);}; | |
| 0 | 434 |
| 9 | 435 bool isAhead (bzVec2 target, float cosThreshold) |
| 436 { | |
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437 bzVec2 targetDirection = target - m_position; |
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438 targetDirection.normalize(); |
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439 return bzDot(m_forward, targetDirection) > cosThreshold; |
| 9 | 440 } |
| 0 | 441 |
| 9 | 442 bool isAside (bzVec2 target, float cosThreshold) |
| 443 { | |
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444 bzVec2 targetDirection = target - m_position; |
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445 targetDirection.normalize(); |
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446 float dp = bzDot(m_forward, targetDirection); |
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447 return (dp < cosThreshold) && (dp > -cosThreshold); |
| 9 | 448 } |
| 0 | 449 |
| 9 | 450 bool isBehind (bzVec2 target, float cosThreshold) |
| 451 { | |
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452 bzVec2 targetDirection = target - m_position; |
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453 targetDirection.normalize(); |
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454 return bzDot(m_forward, targetDirection) < cosThreshold; |
| 9 | 455 } |
| 456 | |
| 457 private: | |
| 458 | |
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459 Ship m_ship; |
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460 |
| 9 | 461 bzVec2 m_position; |
| 462 bzVec2 m_velocity; | |
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463 bzVec2 m_up; |
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464 bzVec2 m_side; |
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465 bzVec2 m_forward; |
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466 |
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467 float m_speed = 0; |
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468 float m_maxForce = 0; |
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469 |
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470 // Wander behavior |
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471 float m_wanderSide; |
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472 float m_wanderUp; |
| 9 | 473 } |