| | | 1 | | //======================================================================= |
| | | 2 | | // ContactNormalImpulse3D.cs |
| | | 3 | | //======================================================================= |
| | | 4 | | // MIT License, Copyright (c) 2026–present David Oravsky (mrdav30) |
| | | 5 | | // See LICENSE file in the project root for full license information. |
| | | 6 | | //======================================================================= |
| | | 7 | | |
| | | 8 | | using FixedMathSharp; |
| | | 9 | | using FixedMathSharp.Geometry; |
| | | 10 | | using System.Runtime.CompilerServices; |
| | | 11 | | |
| | | 12 | | namespace Gravitas.CollisionHandling; |
| | | 13 | | |
| | | 14 | | /// <summary> |
| | | 15 | | /// Side-effect-free 3D contact-normal impulse result for two participants. |
| | | 16 | | /// </summary> |
| | | 17 | | internal readonly struct ContactNormalImpulseResult3D |
| | | 18 | | { |
| | | 19 | | public ContactNormalImpulseResult3D( |
| | | 20 | | Fixed64 normalVelocity, |
| | | 21 | | Fixed64 impulseScalar, |
| | | 22 | | Vector3d linearVelocityDeltaA, |
| | | 23 | | Vector3d angularVelocityDeltaA, |
| | | 24 | | Vector3d linearVelocityDeltaB, |
| | | 25 | | Vector3d angularVelocityDeltaB) |
| | 7693 | 26 | | : this( |
| | 7693 | 27 | | normalVelocity, |
| | 7693 | 28 | | impulseScalar, |
| | 7693 | 29 | | impulseScalar, |
| | 7693 | 30 | | linearVelocityDeltaA, |
| | 7693 | 31 | | angularVelocityDeltaA, |
| | 7693 | 32 | | linearVelocityDeltaB, |
| | 7693 | 33 | | angularVelocityDeltaB) |
| | | 34 | | { |
| | 7693 | 35 | | } |
| | | 36 | | |
| | | 37 | | public ContactNormalImpulseResult3D( |
| | | 38 | | Fixed64 normalVelocity, |
| | | 39 | | Fixed64 impulseScalar, |
| | | 40 | | Fixed64 appliedImpulseScalar, |
| | | 41 | | Vector3d linearVelocityDeltaA, |
| | | 42 | | Vector3d angularVelocityDeltaA, |
| | | 43 | | Vector3d linearVelocityDeltaB, |
| | | 44 | | Vector3d angularVelocityDeltaB, |
| | | 45 | | bool hasRepresentableNormalVelocity = true, |
| | | 46 | | bool hasRepresentableAppliedImpulse = true) |
| | | 47 | | { |
| | 9082 | 48 | | NormalVelocity = normalVelocity; |
| | 9082 | 49 | | ImpulseScalar = impulseScalar; |
| | 9082 | 50 | | AppliedImpulseScalar = appliedImpulseScalar; |
| | 9082 | 51 | | LinearVelocityDeltaA = linearVelocityDeltaA; |
| | 9082 | 52 | | AngularVelocityDeltaA = angularVelocityDeltaA; |
| | 9082 | 53 | | LinearVelocityDeltaB = linearVelocityDeltaB; |
| | 9082 | 54 | | AngularVelocityDeltaB = angularVelocityDeltaB; |
| | 9082 | 55 | | HasRepresentableNormalVelocity = hasRepresentableNormalVelocity; |
| | 9082 | 56 | | HasRepresentableAppliedImpulse = hasRepresentableAppliedImpulse; |
| | 9082 | 57 | | } |
| | | 58 | | |
| | | 59 | | public Fixed64 NormalVelocity { get; } |
| | | 60 | | |
| | | 61 | | public Fixed64 ImpulseScalar { get; } |
| | | 62 | | |
| | | 63 | | public Fixed64 AppliedImpulseScalar { get; } |
| | | 64 | | |
| | | 65 | | public bool HasRepresentableNormalVelocity { get; } |
| | | 66 | | |
| | | 67 | | public bool HasRepresentableAppliedImpulse { get; } |
| | | 68 | | |
| | | 69 | | public Vector3d LinearVelocityDeltaA { get; } |
| | | 70 | | |
| | | 71 | | public Vector3d AngularVelocityDeltaA { get; } |
| | | 72 | | |
| | | 73 | | public Vector3d LinearVelocityDeltaB { get; } |
| | | 74 | | |
| | | 75 | | public Vector3d AngularVelocityDeltaB { get; } |
| | | 76 | | } |
| | | 77 | | |
| | | 78 | | /// <summary> |
| | | 79 | | /// Side-effect-free 3D velocity deltas for a normal response whose impulse |
| | | 80 | | /// scalar does not need to be representable. |
| | | 81 | | /// </summary> |
| | | 82 | | internal readonly struct ContactNormalVelocityDeltaResult3D |
| | | 83 | | { |
| | | 84 | | public ContactNormalVelocityDeltaResult3D( |
| | | 85 | | Fixed64 normalVelocity, |
| | | 86 | | Vector3d linearVelocityDeltaA, |
| | | 87 | | Vector3d angularVelocityDeltaA, |
| | | 88 | | Vector3d linearVelocityDeltaB, |
| | | 89 | | Vector3d angularVelocityDeltaB) |
| | | 90 | | : this( |
| | | 91 | | normalVelocity, |
| | | 92 | | linearVelocityDeltaA, |
| | | 93 | | angularVelocityDeltaA, |
| | | 94 | | linearVelocityDeltaB, |
| | | 95 | | angularVelocityDeltaB, |
| | | 96 | | normalVelocity < Fixed64.Zero, |
| | | 97 | | hasRepresentableNormalVelocity: true) |
| | | 98 | | { |
| | | 99 | | } |
| | | 100 | | |
| | | 101 | | public ContactNormalVelocityDeltaResult3D( |
| | | 102 | | Fixed64 normalVelocity, |
| | | 103 | | Vector3d linearVelocityDeltaA, |
| | | 104 | | Vector3d angularVelocityDeltaA, |
| | | 105 | | Vector3d linearVelocityDeltaB, |
| | | 106 | | Vector3d angularVelocityDeltaB, |
| | | 107 | | bool isClosing, |
| | | 108 | | bool hasRepresentableNormalVelocity) |
| | | 109 | | { |
| | | 110 | | NormalVelocity = normalVelocity; |
| | | 111 | | LinearVelocityDeltaA = linearVelocityDeltaA; |
| | | 112 | | AngularVelocityDeltaA = angularVelocityDeltaA; |
| | | 113 | | LinearVelocityDeltaB = linearVelocityDeltaB; |
| | | 114 | | AngularVelocityDeltaB = angularVelocityDeltaB; |
| | | 115 | | IsClosing = isClosing; |
| | | 116 | | HasRepresentableNormalVelocity = hasRepresentableNormalVelocity; |
| | | 117 | | } |
| | | 118 | | |
| | | 119 | | public Fixed64 NormalVelocity { get; } |
| | | 120 | | |
| | | 121 | | public bool IsClosing { get; } |
| | | 122 | | |
| | | 123 | | public bool HasRepresentableNormalVelocity { get; } |
| | | 124 | | |
| | | 125 | | public Vector3d LinearVelocityDeltaA { get; } |
| | | 126 | | |
| | | 127 | | public Vector3d AngularVelocityDeltaA { get; } |
| | | 128 | | |
| | | 129 | | public Vector3d LinearVelocityDeltaB { get; } |
| | | 130 | | |
| | | 131 | | public Vector3d AngularVelocityDeltaB { get; } |
| | | 132 | | } |
| | | 133 | | |
| | | 134 | | internal readonly struct ContactEffectiveMassTerms3D |
| | | 135 | | { |
| | | 136 | | internal ContactEffectiveMassTerms3D( |
| | | 137 | | Fixed64 linearA, |
| | | 138 | | Fixed64 linearB, |
| | | 139 | | Fixed64 angularA, |
| | | 140 | | Fixed64 angularB) |
| | | 141 | | { |
| | | 142 | | LinearA = linearA; |
| | | 143 | | LinearB = linearB; |
| | | 144 | | AngularA = angularA; |
| | | 145 | | AngularB = angularB; |
| | | 146 | | } |
| | | 147 | | |
| | | 148 | | internal Fixed64 LinearA { get; } |
| | | 149 | | |
| | | 150 | | internal Fixed64 LinearB { get; } |
| | | 151 | | |
| | | 152 | | internal Fixed64 AngularA { get; } |
| | | 153 | | |
| | | 154 | | internal Fixed64 AngularB { get; } |
| | | 155 | | |
| | | 156 | | internal Fixed64 SaturatedSum => |
| | | 157 | | LinearA + LinearB + AngularA + AngularB; |
| | | 158 | | |
| | | 159 | | internal bool TryGetValue(out Fixed64 value) |
| | | 160 | | { |
| | | 161 | | bool resolved = |
| | | 162 | | Fixed64.TryAdd(LinearA, LinearB, out Fixed64 linear); |
| | | 163 | | resolved &= Fixed64.TryAdd( |
| | | 164 | | linear, |
| | | 165 | | AngularA, |
| | | 166 | | out Fixed64 first); |
| | | 167 | | resolved &= Fixed64.TryAdd(first, AngularB, out value); |
| | | 168 | | if (!resolved) |
| | | 169 | | value = default; |
| | | 170 | | return resolved; |
| | | 171 | | } |
| | | 172 | | } |
| | | 173 | | |
| | | 174 | | /// <summary> |
| | | 175 | | /// Calculates allocation-free 3D contact-point normal response without mutating either body. |
| | | 176 | | /// </summary> |
| | | 177 | | internal static class ContactNormalImpulse3D |
| | | 178 | | { |
| | | 179 | | internal static bool TryCalculateVelocityDeltas( |
| | | 180 | | SolidBody? bodyA, |
| | | 181 | | Vector3d linearVelocityA, |
| | | 182 | | Vector3d angularVelocityA, |
| | | 183 | | Vector3d relativeContactPointA, |
| | | 184 | | SolidBody? bodyB, |
| | | 185 | | Vector3d linearVelocityB, |
| | | 186 | | Vector3d angularVelocityB, |
| | | 187 | | Vector3d relativeContactPointB, |
| | | 188 | | Vector3d normal, |
| | | 189 | | Fixed64 restitution, |
| | | 190 | | Fixed64 restitutionVelocityThreshold, |
| | | 191 | | out ContactNormalVelocityDeltaResult3D result) |
| | | 192 | | { |
| | | 193 | | result = default; |
| | | 194 | | if (!TryComputeNormalVelocity( |
| | | 195 | | linearVelocityA, |
| | | 196 | | angularVelocityA, |
| | | 197 | | relativeContactPointA, |
| | | 198 | | linearVelocityB, |
| | | 199 | | angularVelocityB, |
| | | 200 | | relativeContactPointB, |
| | | 201 | | normal, |
| | | 202 | | out Fixed64 normalVelocity)) |
| | | 203 | | { |
| | | 204 | | return false; |
| | | 205 | | } |
| | | 206 | | |
| | | 207 | | if (normalVelocity >= Fixed64.Zero) |
| | | 208 | | { |
| | | 209 | | result = ZeroVelocityDelta(normalVelocity); |
| | | 210 | | return true; |
| | | 211 | | } |
| | | 212 | | |
| | | 213 | | if (!TryComputeDenominator( |
| | | 214 | | bodyA, |
| | | 215 | | relativeContactPointA, |
| | | 216 | | bodyB, |
| | | 217 | | relativeContactPointB, |
| | | 218 | | normal, |
| | | 219 | | out ContactEffectiveMassTerms3D denominator) |
| | | 220 | | || denominator.SaturatedSum <= Fixed64.Zero) |
| | | 221 | | { |
| | | 222 | | return false; |
| | | 223 | | } |
| | | 224 | | |
| | | 225 | | Fixed64 appliedRestitution = normalVelocity < -restitutionVelocityThreshold |
| | | 226 | | ? restitution |
| | | 227 | | : Fixed64.Zero; |
| | | 228 | | Fixed64 responseFactor = -(Fixed64.One + appliedRestitution); |
| | | 229 | | bool linearAResolved = TryResolveVelocityDelta( |
| | | 230 | | bodyA?.ProjectLinearMotion(-normal) ?? Vector3d.Zero, |
| | | 231 | | normalVelocity, |
| | | 232 | | responseFactor, |
| | | 233 | | bodyA?.EffectiveInverseMass ?? Fixed64.Zero, |
| | | 234 | | denominator, |
| | | 235 | | out Vector3d linearVelocityDeltaA); |
| | | 236 | | bool angularAResolved = TryResolveAngularVelocityDelta( |
| | | 237 | | bodyA, |
| | | 238 | | relativeContactPointA, |
| | | 239 | | -normal, |
| | | 240 | | normalVelocity, |
| | | 241 | | responseFactor, |
| | | 242 | | denominator, |
| | | 243 | | out Vector3d angularVelocityDeltaA); |
| | | 244 | | bool linearBResolved = TryResolveVelocityDelta( |
| | | 245 | | bodyB?.ProjectLinearMotion(normal) ?? Vector3d.Zero, |
| | | 246 | | normalVelocity, |
| | | 247 | | responseFactor, |
| | | 248 | | bodyB?.EffectiveInverseMass ?? Fixed64.Zero, |
| | | 249 | | denominator, |
| | | 250 | | out Vector3d linearVelocityDeltaB); |
| | | 251 | | bool angularBResolved = TryResolveAngularVelocityDelta( |
| | | 252 | | bodyB, |
| | | 253 | | relativeContactPointB, |
| | | 254 | | normal, |
| | | 255 | | normalVelocity, |
| | | 256 | | responseFactor, |
| | | 257 | | denominator, |
| | | 258 | | out Vector3d angularVelocityDeltaB); |
| | | 259 | | if (!(linearAResolved |
| | | 260 | | & angularAResolved |
| | | 261 | | & linearBResolved |
| | | 262 | | & angularBResolved)) |
| | | 263 | | { |
| | | 264 | | return false; |
| | | 265 | | } |
| | | 266 | | |
| | | 267 | | result = new ContactNormalVelocityDeltaResult3D( |
| | | 268 | | normalVelocity, |
| | | 269 | | linearVelocityDeltaA, |
| | | 270 | | angularVelocityDeltaA, |
| | | 271 | | linearVelocityDeltaB, |
| | | 272 | | angularVelocityDeltaB); |
| | | 273 | | return true; |
| | | 274 | | } |
| | | 275 | | |
| | | 276 | | internal static bool TryCalculateVelocityDeltasExact( |
| | | 277 | | SolidBody? bodyA, |
| | | 278 | | Vector3d linearVelocityA, |
| | | 279 | | Vector3d angularVelocityA, |
| | | 280 | | in ExactLever3D relativeContactPointA, |
| | | 281 | | SolidBody? bodyB, |
| | | 282 | | Vector3d linearVelocityB, |
| | | 283 | | Vector3d angularVelocityB, |
| | | 284 | | in ExactLever3D relativeContactPointB, |
| | | 285 | | Vector3d normal, |
| | | 286 | | Fixed64 restitution, |
| | | 287 | | Fixed64 restitutionVelocityThreshold, |
| | | 288 | | out ContactNormalVelocityDeltaResult3D result) |
| | | 289 | | { |
| | | 290 | | result = default; |
| | | 291 | | if (!ExactContactLever3D.TryGetNormalResponse( |
| | | 292 | | bodyA, |
| | | 293 | | linearVelocityA, |
| | | 294 | | angularVelocityA, |
| | | 295 | | relativeContactPointA, |
| | | 296 | | bodyB, |
| | | 297 | | linearVelocityB, |
| | | 298 | | angularVelocityB, |
| | | 299 | | relativeContactPointB, |
| | | 300 | | normal, |
| | | 301 | | restitution, |
| | | 302 | | restitutionVelocityThreshold, |
| | | 303 | | out ExactNormalResponse3D response)) |
| | | 304 | | { |
| | | 305 | | return false; |
| | | 306 | | } |
| | | 307 | | |
| | | 308 | | bool hasNormalVelocity = |
| | | 309 | | response.TryGetNormalVelocity(out Fixed64 normalVelocity); |
| | | 310 | | result = new ContactNormalVelocityDeltaResult3D( |
| | | 311 | | normalVelocity, |
| | | 312 | | response.FirstLinearVelocityDelta, |
| | | 313 | | response.FirstAngularVelocityDelta, |
| | | 314 | | response.SecondLinearVelocityDelta, |
| | | 315 | | response.SecondAngularVelocityDelta, |
| | | 316 | | response.IsClosing, |
| | | 317 | | hasNormalVelocity); |
| | | 318 | | return true; |
| | | 319 | | } |
| | | 320 | | |
| | | 321 | | internal static ContactNormalImpulseResult3D CalculateAccumulatedDelta( |
| | | 322 | | SolidBody? bodyA, |
| | | 323 | | Vector3d linearVelocityA, |
| | | 324 | | Vector3d angularVelocityA, |
| | | 325 | | Vector3d relativeContactPointA, |
| | | 326 | | SolidBody? bodyB, |
| | | 327 | | Vector3d linearVelocityB, |
| | | 328 | | Vector3d angularVelocityB, |
| | | 329 | | Vector3d relativeContactPointB, |
| | | 330 | | Vector3d normal, |
| | | 331 | | Fixed64 restitution, |
| | | 332 | | Fixed64 restitutionVelocityThreshold, |
| | | 333 | | Fixed64 accumulatedImpulse, |
| | | 334 | | Fixed64 positiveImpulseScale, |
| | | 335 | | Fixed64 negativeImpulseScale) |
| | | 336 | | { |
| | | 337 | | _ = TryCalculateAccumulatedDelta( |
| | | 338 | | bodyA, |
| | | 339 | | linearVelocityA, |
| | | 340 | | angularVelocityA, |
| | | 341 | | relativeContactPointA, |
| | | 342 | | bodyB, |
| | | 343 | | linearVelocityB, |
| | | 344 | | angularVelocityB, |
| | | 345 | | relativeContactPointB, |
| | | 346 | | normal, |
| | | 347 | | restitution, |
| | | 348 | | restitutionVelocityThreshold, |
| | | 349 | | accumulatedImpulse, |
| | | 350 | | positiveImpulseScale, |
| | | 351 | | negativeImpulseScale, |
| | | 352 | | out ContactNormalImpulseResult3D result); |
| | | 353 | | return result; |
| | | 354 | | } |
| | | 355 | | |
| | | 356 | | internal static bool TryCalculateAccumulatedDelta( |
| | | 357 | | SolidBody? bodyA, |
| | | 358 | | Vector3d linearVelocityA, |
| | | 359 | | Vector3d angularVelocityA, |
| | | 360 | | Vector3d relativeContactPointA, |
| | | 361 | | SolidBody? bodyB, |
| | | 362 | | Vector3d linearVelocityB, |
| | | 363 | | Vector3d angularVelocityB, |
| | | 364 | | Vector3d relativeContactPointB, |
| | | 365 | | Vector3d normal, |
| | | 366 | | Fixed64 restitution, |
| | | 367 | | Fixed64 restitutionVelocityThreshold, |
| | | 368 | | Fixed64 accumulatedImpulse, |
| | | 369 | | Fixed64 positiveImpulseScale, |
| | | 370 | | Fixed64 negativeImpulseScale, |
| | | 371 | | out ContactNormalImpulseResult3D result) |
| | | 372 | | { |
| | | 373 | | result = default; |
| | | 374 | | if (!TryComputeNormalVelocity( |
| | | 375 | | linearVelocityA, |
| | | 376 | | angularVelocityA, |
| | | 377 | | relativeContactPointA, |
| | | 378 | | linearVelocityB, |
| | | 379 | | angularVelocityB, |
| | | 380 | | relativeContactPointB, |
| | | 381 | | normal, |
| | | 382 | | out Fixed64 normalVelocity) |
| | | 383 | | || !TryComputeDenominator( |
| | | 384 | | bodyA, |
| | | 385 | | relativeContactPointA, |
| | | 386 | | bodyB, |
| | | 387 | | relativeContactPointB, |
| | | 388 | | normal, |
| | | 389 | | out ContactEffectiveMassTerms3D denominator)) |
| | | 390 | | { |
| | | 391 | | return false; |
| | | 392 | | } |
| | | 393 | | |
| | | 394 | | if (denominator.SaturatedSum <= Fixed64.Zero) |
| | | 395 | | { |
| | | 396 | | result = Zero(normalVelocity); |
| | | 397 | | return true; |
| | | 398 | | } |
| | | 399 | | |
| | | 400 | | if (!TryCalculateAccumulatedImpulseDelta( |
| | | 401 | | normalVelocity, |
| | | 402 | | denominator, |
| | | 403 | | restitution, |
| | | 404 | | restitutionVelocityThreshold, |
| | | 405 | | accumulatedImpulse, |
| | | 406 | | positiveImpulseScale, |
| | | 407 | | negativeImpulseScale, |
| | | 408 | | out Fixed64 impulseScalar)) |
| | | 409 | | { |
| | | 410 | | return false; |
| | | 411 | | } |
| | | 412 | | |
| | | 413 | | if (impulseScalar == Fixed64.Zero) |
| | | 414 | | { |
| | | 415 | | result = Zero(normalVelocity); |
| | | 416 | | return true; |
| | | 417 | | } |
| | | 418 | | |
| | | 419 | | Vector3d impulseB = normal * impulseScalar; |
| | | 420 | | Vector3d impulseA = -impulseB; |
| | | 421 | | bool linearAResolved = TryComputeLinearVelocityDelta( |
| | | 422 | | bodyA, |
| | | 423 | | impulseA, |
| | | 424 | | out Vector3d linearVelocityDeltaA); |
| | | 425 | | bool angularAResolved = TryComputeAngularVelocityDelta( |
| | | 426 | | bodyA, |
| | | 427 | | relativeContactPointA, |
| | | 428 | | impulseA, |
| | | 429 | | out Vector3d angularVelocityDeltaA); |
| | | 430 | | bool linearBResolved = TryComputeLinearVelocityDelta( |
| | | 431 | | bodyB, |
| | | 432 | | impulseB, |
| | | 433 | | out Vector3d linearVelocityDeltaB); |
| | | 434 | | bool angularBResolved = TryComputeAngularVelocityDelta( |
| | | 435 | | bodyB, |
| | | 436 | | relativeContactPointB, |
| | | 437 | | impulseB, |
| | | 438 | | out Vector3d angularVelocityDeltaB); |
| | | 439 | | if (!(linearAResolved |
| | | 440 | | & angularAResolved |
| | | 441 | | & linearBResolved |
| | | 442 | | & angularBResolved)) |
| | | 443 | | { |
| | | 444 | | return false; |
| | | 445 | | } |
| | | 446 | | |
| | | 447 | | result = new ContactNormalImpulseResult3D( |
| | | 448 | | normalVelocity, |
| | | 449 | | impulseScalar, |
| | | 450 | | linearVelocityDeltaA, |
| | | 451 | | angularVelocityDeltaA, |
| | | 452 | | linearVelocityDeltaB, |
| | | 453 | | angularVelocityDeltaB); |
| | | 454 | | return true; |
| | | 455 | | } |
| | | 456 | | |
| | | 457 | | internal static bool TryCalculateAccumulatedDeltaExact( |
| | | 458 | | SolidBody? bodyA, |
| | | 459 | | Vector3d linearVelocityA, |
| | | 460 | | Vector3d angularVelocityA, |
| | | 461 | | in ExactLever3D relativeContactPointA, |
| | | 462 | | SolidBody? bodyB, |
| | | 463 | | Vector3d linearVelocityB, |
| | | 464 | | Vector3d angularVelocityB, |
| | | 465 | | in ExactLever3D relativeContactPointB, |
| | | 466 | | Vector3d normal, |
| | | 467 | | Fixed64 restitution, |
| | | 468 | | Fixed64 restitutionVelocityThreshold, |
| | | 469 | | Fixed64 accumulatedImpulse, |
| | | 470 | | Fixed64 positiveImpulseScale, |
| | | 471 | | Fixed64 negativeImpulseScale, |
| | | 472 | | out ContactNormalImpulseResult3D result) |
| | | 473 | | { |
| | | 474 | | result = default; |
| | | 475 | | if (!ExactContactLever3D.TryGetAccumulatedNormalResponse( |
| | | 476 | | bodyA, |
| | | 477 | | linearVelocityA, |
| | | 478 | | angularVelocityA, |
| | | 479 | | relativeContactPointA, |
| | | 480 | | bodyB, |
| | | 481 | | linearVelocityB, |
| | | 482 | | angularVelocityB, |
| | | 483 | | relativeContactPointB, |
| | | 484 | | normal, |
| | | 485 | | restitution, |
| | | 486 | | restitutionVelocityThreshold, |
| | | 487 | | accumulatedImpulse, |
| | | 488 | | positiveImpulseScale, |
| | | 489 | | negativeImpulseScale, |
| | | 490 | | out ExactNormalResponse3D response)) |
| | | 491 | | { |
| | | 492 | | return false; |
| | | 493 | | } |
| | | 494 | | |
| | | 495 | | bool hasNormalVelocity = |
| | | 496 | | response.TryGetNormalVelocity(out Fixed64 normalVelocity); |
| | | 497 | | bool hasAppliedImpulse = |
| | | 498 | | response.TryGetAppliedImpulse(out Fixed64 appliedImpulse); |
| | | 499 | | Fixed64 impulseScalar; |
| | | 500 | | if (response.TryGetAccumulatedImpulse( |
| | | 501 | | out Fixed64 newAccumulatedImpulse)) |
| | | 502 | | { |
| | | 503 | | // Both values are nonnegative, so their difference is always in |
| | | 504 | | // [-Fixed64.MaxValue, Fixed64.MaxValue]. |
| | | 505 | | impulseScalar = newAccumulatedImpulse - accumulatedImpulse; |
| | | 506 | | } |
| | | 507 | | else |
| | | 508 | | { |
| | | 509 | | impulseScalar = -accumulatedImpulse; |
| | | 510 | | } |
| | | 511 | | |
| | | 512 | | result = new ContactNormalImpulseResult3D( |
| | | 513 | | normalVelocity, |
| | | 514 | | impulseScalar, |
| | | 515 | | appliedImpulse, |
| | | 516 | | response.FirstLinearVelocityDelta, |
| | | 517 | | response.FirstAngularVelocityDelta, |
| | | 518 | | response.SecondLinearVelocityDelta, |
| | | 519 | | response.SecondAngularVelocityDelta, |
| | | 520 | | hasNormalVelocity, |
| | | 521 | | hasAppliedImpulse); |
| | | 522 | | return true; |
| | | 523 | | } |
| | | 524 | | |
| | | 525 | | private static bool TryCalculateAccumulatedImpulseDelta( |
| | | 526 | | Fixed64 normalVelocity, |
| | | 527 | | in ContactEffectiveMassTerms3D denominator, |
| | | 528 | | Fixed64 restitution, |
| | | 529 | | Fixed64 restitutionVelocityThreshold, |
| | | 530 | | Fixed64 accumulatedImpulse, |
| | | 531 | | Fixed64 positiveImpulseScale, |
| | | 532 | | Fixed64 negativeImpulseScale, |
| | | 533 | | out Fixed64 impulseDelta) |
| | | 534 | | { |
| | | 535 | | Fixed64 appliedRestitution = |
| | | 536 | | normalVelocity < -restitutionVelocityThreshold |
| | | 537 | | ? restitution |
| | | 538 | | : Fixed64.Zero; |
| | | 539 | | Fixed64 responseFactor = -(Fixed64.One + appliedRestitution); |
| | | 540 | | Fixed64 impulseScale = normalVelocity < Fixed64.Zero |
| | | 541 | | ? positiveImpulseScale |
| | | 542 | | : negativeImpulseScale; |
| | | 543 | | if (!Fixed64.TryMultiplyDivideBySum( |
| | | 544 | | normalVelocity, |
| | | 545 | | responseFactor, |
| | | 546 | | impulseScale, |
| | | 547 | | Fixed64.One, |
| | | 548 | | denominator.LinearA, |
| | | 549 | | denominator.LinearB, |
| | | 550 | | denominator.AngularA, |
| | | 551 | | denominator.AngularB, |
| | | 552 | | out Fixed64 scaledImpulse)) |
| | | 553 | | { |
| | | 554 | | impulseDelta = default; |
| | | 555 | | return normalVelocity >= Fixed64.Zero |
| | | 556 | | && responseFactor <= Fixed64.Zero |
| | | 557 | | && impulseScale >= Fixed64.Zero |
| | | 558 | | && accumulatedImpulse >= Fixed64.Zero |
| | | 559 | | && Fixed64.TrySubtract( |
| | | 560 | | Fixed64.Zero, |
| | | 561 | | accumulatedImpulse, |
| | | 562 | | out impulseDelta); |
| | | 563 | | } |
| | | 564 | | |
| | | 565 | | if (!Fixed64.TryAdd( |
| | | 566 | | accumulatedImpulse, |
| | | 567 | | scaledImpulse, |
| | | 568 | | out Fixed64 accumulated)) |
| | | 569 | | { |
| | | 570 | | impulseDelta = default; |
| | | 571 | | return false; |
| | | 572 | | } |
| | | 573 | | |
| | | 574 | | return Fixed64.TrySubtract( |
| | | 575 | | FixedMath.Max(Fixed64.Zero, accumulated), |
| | | 576 | | accumulatedImpulse, |
| | | 577 | | out impulseDelta); |
| | | 578 | | } |
| | | 579 | | |
| | | 580 | | [MethodImpl(MethodImplOptions.AggressiveInlining)] |
| | | 581 | | private static Fixed64 GetConstrainedInverseMass(SolidBody? body, Vector3d axis) => |
| | | 582 | | body?.GetConstrainedInverseMass(axis) ?? Fixed64.Zero; |
| | | 583 | | |
| | | 584 | | internal static bool TryComputeNormalVelocity( |
| | | 585 | | Vector3d linearVelocityA, |
| | | 586 | | Vector3d angularVelocityA, |
| | | 587 | | Vector3d relativeContactPointA, |
| | | 588 | | Vector3d linearVelocityB, |
| | | 589 | | Vector3d angularVelocityB, |
| | | 590 | | Vector3d relativeContactPointB, |
| | | 591 | | Vector3d normal, |
| | | 592 | | out Fixed64 normalVelocity) |
| | | 593 | | { |
| | | 594 | | if (ContactResponseArithmetic3D.CanUseFastPointVelocity( |
| | | 595 | | linearVelocityA, |
| | | 596 | | angularVelocityA, |
| | | 597 | | relativeContactPointA, |
| | | 598 | | linearVelocityB, |
| | | 599 | | angularVelocityB, |
| | | 600 | | relativeContactPointB, |
| | | 601 | | normal)) |
| | | 602 | | { |
| | | 603 | | Vector3d fastPointVelocityA = linearVelocityA |
| | | 604 | | + Vector3d.Cross( |
| | | 605 | | angularVelocityA, |
| | | 606 | | relativeContactPointA); |
| | | 607 | | Vector3d fastPointVelocityB = linearVelocityB |
| | | 608 | | + Vector3d.Cross( |
| | | 609 | | angularVelocityB, |
| | | 610 | | relativeContactPointB); |
| | | 611 | | normalVelocity = Vector3d.Dot( |
| | | 612 | | fastPointVelocityB - fastPointVelocityA, |
| | | 613 | | normal); |
| | | 614 | | return true; |
| | | 615 | | } |
| | | 616 | | |
| | | 617 | | bool resolved = ContactResponseArithmetic3D.TryCross( |
| | | 618 | | angularVelocityA, |
| | | 619 | | relativeContactPointA, |
| | | 620 | | out Vector3d angularA) |
| | | 621 | | & ContactResponseArithmetic3D.TryCross( |
| | | 622 | | angularVelocityB, |
| | | 623 | | relativeContactPointB, |
| | | 624 | | out Vector3d angularB); |
| | | 625 | | if (!resolved |
| | | 626 | | || !Vector3d.TryAdd( |
| | | 627 | | linearVelocityA, |
| | | 628 | | angularA, |
| | | 629 | | out Vector3d pointVelocityA) |
| | | 630 | | || !Vector3d.TryAdd( |
| | | 631 | | linearVelocityB, |
| | | 632 | | angularB, |
| | | 633 | | out Vector3d pointVelocityB) |
| | | 634 | | || !Vector3d.TrySubtract( |
| | | 635 | | pointVelocityB, |
| | | 636 | | pointVelocityA, |
| | | 637 | | out Vector3d relativeVelocity)) |
| | | 638 | | { |
| | | 639 | | normalVelocity = default; |
| | | 640 | | return false; |
| | | 641 | | } |
| | | 642 | | |
| | | 643 | | return ContactResponseArithmetic3D.TryDot( |
| | | 644 | | relativeVelocity, |
| | | 645 | | normal, |
| | | 646 | | out normalVelocity); |
| | | 647 | | } |
| | | 648 | | |
| | | 649 | | private static bool TryComputeDenominator( |
| | | 650 | | SolidBody? bodyA, |
| | | 651 | | Vector3d relativeContactPointA, |
| | | 652 | | SolidBody? bodyB, |
| | | 653 | | Vector3d relativeContactPointB, |
| | | 654 | | Vector3d normal, |
| | | 655 | | out ContactEffectiveMassTerms3D denominator) |
| | | 656 | | { |
| | | 657 | | denominator = default; |
| | | 658 | | bool angularAResolved = TryComputeAngularDenominator( |
| | | 659 | | bodyA, |
| | | 660 | | relativeContactPointA, |
| | | 661 | | normal, |
| | | 662 | | out Fixed64 angularA); |
| | | 663 | | bool angularBResolved = TryComputeAngularDenominator( |
| | | 664 | | bodyB, |
| | | 665 | | relativeContactPointB, |
| | | 666 | | normal, |
| | | 667 | | out Fixed64 angularB); |
| | | 668 | | if (!(angularAResolved & angularBResolved)) |
| | | 669 | | { |
| | | 670 | | return false; |
| | | 671 | | } |
| | | 672 | | |
| | | 673 | | denominator = new ContactEffectiveMassTerms3D( |
| | | 674 | | GetConstrainedInverseMass(bodyA, normal), |
| | | 675 | | GetConstrainedInverseMass(bodyB, normal), |
| | | 676 | | angularA, |
| | | 677 | | angularB); |
| | | 678 | | return true; |
| | | 679 | | } |
| | | 680 | | |
| | | 681 | | internal static bool TryComputeAngularDenominator( |
| | | 682 | | SolidBody? body, |
| | | 683 | | Vector3d relativeContactPoint, |
| | | 684 | | Vector3d axis, |
| | | 685 | | out Fixed64 denominator) |
| | | 686 | | { |
| | | 687 | | denominator = Fixed64.Zero; |
| | | 688 | | if (body?.CanRotate != true) |
| | | 689 | | return true; |
| | | 690 | | |
| | | 691 | | Fixed3x3 inverseInertia = |
| | | 692 | | body.GetConstrainedInverseInertiaTensor(); |
| | | 693 | | if (ContactResponseArithmetic3D.CanUseFastAngularResponse( |
| | | 694 | | relativeContactPoint, |
| | | 695 | | axis, |
| | | 696 | | inverseInertia)) |
| | | 697 | | { |
| | | 698 | | Vector3d fastTorqueAxis = |
| | | 699 | | Vector3d.Cross(relativeContactPoint, axis); |
| | | 700 | | Vector3d fastAngularVelocityDelta = |
| | | 701 | | Fixed3x3.TransformDirection( |
| | | 702 | | inverseInertia, |
| | | 703 | | fastTorqueAxis); |
| | | 704 | | Vector3d fastAngular = Vector3d.Cross( |
| | | 705 | | fastAngularVelocityDelta, |
| | | 706 | | relativeContactPoint); |
| | | 707 | | denominator = Vector3d.Dot(fastAngular, axis); |
| | | 708 | | bool responsePreserved = |
| | | 709 | | ContactResponseArithmetic3D.PreservesNonzeroCrossProduct( |
| | | 710 | | relativeContactPoint, |
| | | 711 | | axis, |
| | | 712 | | fastTorqueAxis); |
| | | 713 | | responsePreserved &= |
| | | 714 | | ContactResponseArithmetic3D |
| | | 715 | | .PreservesNonzeroTransformDirection( |
| | | 716 | | inverseInertia, |
| | | 717 | | fastTorqueAxis, |
| | | 718 | | fastAngularVelocityDelta); |
| | | 719 | | responsePreserved &= |
| | | 720 | | ContactResponseArithmetic3D |
| | | 721 | | .PreservesNonzeroCrossProduct( |
| | | 722 | | fastAngularVelocityDelta, |
| | | 723 | | relativeContactPoint, |
| | | 724 | | fastAngular); |
| | | 725 | | responsePreserved &= |
| | | 726 | | ContactResponseArithmetic3D.PreservesNonzeroDotProduct( |
| | | 727 | | fastAngular, |
| | | 728 | | axis, |
| | | 729 | | denominator); |
| | | 730 | | if (!responsePreserved) |
| | | 731 | | { |
| | | 732 | | denominator = default; |
| | | 733 | | return false; |
| | | 734 | | } |
| | | 735 | | |
| | | 736 | | denominator = FixedMath.Max(denominator, Fixed64.Zero); |
| | | 737 | | return true; |
| | | 738 | | } |
| | | 739 | | |
| | | 740 | | if (!ContactResponseArithmetic3D.TryCross( |
| | | 741 | | relativeContactPoint, |
| | | 742 | | axis, |
| | | 743 | | out Vector3d torqueAxis) |
| | | 744 | | || !ContactResponseArithmetic3D.TryTransformDirection( |
| | | 745 | | inverseInertia, |
| | | 746 | | torqueAxis, |
| | | 747 | | out Vector3d angularVelocityDelta) |
| | | 748 | | || !ContactResponseArithmetic3D.TryCross( |
| | | 749 | | angularVelocityDelta, |
| | | 750 | | relativeContactPoint, |
| | | 751 | | out Vector3d angular) |
| | | 752 | | || !ContactResponseArithmetic3D.TryDot( |
| | | 753 | | angular, |
| | | 754 | | axis, |
| | | 755 | | out denominator)) |
| | | 756 | | { |
| | | 757 | | denominator = default; |
| | | 758 | | return false; |
| | | 759 | | } |
| | | 760 | | |
| | | 761 | | denominator = FixedMath.Max(denominator, Fixed64.Zero); |
| | | 762 | | return true; |
| | | 763 | | } |
| | | 764 | | |
| | | 765 | | internal static bool TryComputeLinearVelocityDelta( |
| | | 766 | | SolidBody? body, |
| | | 767 | | Vector3d impulse, |
| | | 768 | | out Vector3d velocityDelta) |
| | | 769 | | { |
| | | 770 | | if (body != null) |
| | | 771 | | impulse = body.ProjectLinearMotion(impulse); |
| | | 772 | | |
| | | 773 | | if (!ContactResponseArithmetic3D.TryScale( |
| | | 774 | | impulse, |
| | | 775 | | body?.EffectiveInverseMass ?? Fixed64.Zero, |
| | | 776 | | out velocityDelta)) |
| | | 777 | | { |
| | | 778 | | return false; |
| | | 779 | | } |
| | | 780 | | |
| | | 781 | | return true; |
| | | 782 | | } |
| | | 783 | | |
| | | 784 | | internal static bool TryComputeAngularVelocityDelta( |
| | | 785 | | SolidBody? body, |
| | | 786 | | Vector3d relativeContactPoint, |
| | | 787 | | Vector3d impulse, |
| | | 788 | | out Vector3d velocityDelta) |
| | | 789 | | { |
| | | 790 | | velocityDelta = Vector3d.Zero; |
| | | 791 | | if (body?.CanRotate != true) |
| | | 792 | | return true; |
| | | 793 | | |
| | | 794 | | Fixed3x3 inverseInertia = |
| | | 795 | | body.GetConstrainedInverseInertiaTensor(); |
| | | 796 | | if (ContactResponseArithmetic3D.CanUseFastAngularResponse( |
| | | 797 | | relativeContactPoint, |
| | | 798 | | impulse, |
| | | 799 | | inverseInertia)) |
| | | 800 | | { |
| | | 801 | | if (!ContactResponseArithmetic3D.TryCross( |
| | | 802 | | relativeContactPoint, |
| | | 803 | | impulse, |
| | | 804 | | out Vector3d torqueAxis)) |
| | | 805 | | return false; |
| | | 806 | | |
| | | 807 | | velocityDelta = Fixed3x3.TransformDirection( |
| | | 808 | | inverseInertia, |
| | | 809 | | torqueAxis); |
| | | 810 | | return ContactResponseArithmetic3D |
| | | 811 | | .PreservesNonzeroTransformDirection( |
| | | 812 | | inverseInertia, |
| | | 813 | | torqueAxis, |
| | | 814 | | velocityDelta); |
| | | 815 | | } |
| | | 816 | | |
| | | 817 | | bool torqueResolved = ContactResponseArithmetic3D.TryCross( |
| | | 818 | | relativeContactPoint, |
| | | 819 | | impulse, |
| | | 820 | | out Vector3d checkedTorqueAxis); |
| | | 821 | | bool transformResolved = |
| | | 822 | | ContactResponseArithmetic3D.TryTransformDirection( |
| | | 823 | | inverseInertia, |
| | | 824 | | checkedTorqueAxis, |
| | | 825 | | out velocityDelta); |
| | | 826 | | return torqueResolved & transformResolved; |
| | | 827 | | } |
| | | 828 | | |
| | | 829 | | private static bool TryResolveAngularVelocityDelta( |
| | | 830 | | SolidBody? body, |
| | | 831 | | Vector3d relativeContactPoint, |
| | | 832 | | Vector3d signedNormal, |
| | | 833 | | Fixed64 normalVelocity, |
| | | 834 | | Fixed64 responseFactor, |
| | | 835 | | in ContactEffectiveMassTerms3D denominator, |
| | | 836 | | out Vector3d velocityDelta) |
| | | 837 | | { |
| | | 838 | | velocityDelta = Vector3d.Zero; |
| | | 839 | | if (body?.CanRotate != true) |
| | | 840 | | return true; |
| | | 841 | | |
| | | 842 | | bool responseResolved = TryComputeAngularVelocityDelta( |
| | | 843 | | body, |
| | | 844 | | relativeContactPoint, |
| | | 845 | | signedNormal, |
| | | 846 | | out Vector3d response); |
| | | 847 | | bool deltaResolved = TryResolveVelocityDelta( |
| | | 848 | | response, |
| | | 849 | | normalVelocity, |
| | | 850 | | responseFactor, |
| | | 851 | | Fixed64.One, |
| | | 852 | | denominator, |
| | | 853 | | out velocityDelta); |
| | | 854 | | return responseResolved & deltaResolved; |
| | | 855 | | } |
| | | 856 | | |
| | | 857 | | private static bool TryResolveVelocityDelta( |
| | | 858 | | Vector3d response, |
| | | 859 | | Fixed64 firstMultiplier, |
| | | 860 | | Fixed64 secondMultiplier, |
| | | 861 | | Fixed64 thirdMultiplier, |
| | | 862 | | in ContactEffectiveMassTerms3D denominator, |
| | | 863 | | out Vector3d velocityDelta) |
| | | 864 | | { |
| | | 865 | | bool xResolved = Fixed64.TryMultiplyDivideBySum( |
| | | 866 | | response.X, |
| | | 867 | | firstMultiplier, |
| | | 868 | | secondMultiplier, |
| | | 869 | | thirdMultiplier, |
| | | 870 | | denominator.LinearA, |
| | | 871 | | denominator.LinearB, |
| | | 872 | | denominator.AngularA, |
| | | 873 | | denominator.AngularB, |
| | | 874 | | out Fixed64 x); |
| | | 875 | | bool yResolved = Fixed64.TryMultiplyDivideBySum( |
| | | 876 | | response.Y, |
| | | 877 | | firstMultiplier, |
| | | 878 | | secondMultiplier, |
| | | 879 | | thirdMultiplier, |
| | | 880 | | denominator.LinearA, |
| | | 881 | | denominator.LinearB, |
| | | 882 | | denominator.AngularA, |
| | | 883 | | denominator.AngularB, |
| | | 884 | | out Fixed64 y); |
| | | 885 | | bool zResolved = Fixed64.TryMultiplyDivideBySum( |
| | | 886 | | response.Z, |
| | | 887 | | firstMultiplier, |
| | | 888 | | secondMultiplier, |
| | | 889 | | thirdMultiplier, |
| | | 890 | | denominator.LinearA, |
| | | 891 | | denominator.LinearB, |
| | | 892 | | denominator.AngularA, |
| | | 893 | | denominator.AngularB, |
| | | 894 | | out Fixed64 z); |
| | | 895 | | velocityDelta = xResolved & yResolved & zResolved |
| | | 896 | | ? new Vector3d(x, y, z) |
| | | 897 | | : default; |
| | | 898 | | return xResolved & yResolved & zResolved; |
| | | 899 | | } |
| | | 900 | | |
| | | 901 | | [MethodImpl(MethodImplOptions.AggressiveInlining)] |
| | | 902 | | private static ContactNormalImpulseResult3D Zero(Fixed64 normalVelocity) => |
| | | 903 | | new( |
| | | 904 | | normalVelocity, |
| | | 905 | | Fixed64.Zero, |
| | | 906 | | Vector3d.Zero, |
| | | 907 | | Vector3d.Zero, |
| | | 908 | | Vector3d.Zero, |
| | | 909 | | Vector3d.Zero); |
| | | 910 | | |
| | | 911 | | [MethodImpl(MethodImplOptions.AggressiveInlining)] |
| | | 912 | | private static ContactNormalVelocityDeltaResult3D ZeroVelocityDelta(Fixed64 normalVelocity) => |
| | | 913 | | new( |
| | | 914 | | normalVelocity, |
| | | 915 | | Vector3d.Zero, |
| | | 916 | | Vector3d.Zero, |
| | | 917 | | Vector3d.Zero, |
| | | 918 | | Vector3d.Zero); |
| | | 919 | | } |