public static void CalculateTimeOfImpact(out TOIOutput output, TOIInput input) { output = default(TOIOutput); output.State = TOIOutputState.Unknown; output.T = input.TMax; Sweep sweepA = input.SweepA; Sweep sweepB = input.SweepB; sweepA.Normalize(); sweepB.Normalize(); FP tMax = input.TMax; FP x = input.ProxyA.Radius + input.ProxyB.Radius; FP fP = TSMath.Max(Settings.LinearSlop, x - 3f * Settings.LinearSlop); FP y = 0.25f * Settings.LinearSlop; Debug.Assert(fP > y); FP fP2 = 0f; int num = 0; TimeOfImpact._distanceInput = (TimeOfImpact._distanceInput ?? new DistanceInput()); TimeOfImpact._distanceInput.ProxyA = input.ProxyA; TimeOfImpact._distanceInput.ProxyB = input.ProxyB; TimeOfImpact._distanceInput.UseRadii = false; while (true) { Transform transformA; sweepA.GetTransform(out transformA, fP2); Transform transformB; sweepB.GetTransform(out transformB, fP2); TimeOfImpact._distanceInput.TransformA = transformA; TimeOfImpact._distanceInput.TransformB = transformB; DistanceOutput distanceOutput; SimplexCache simplexCache; Distance.ComputeDistance(out distanceOutput, out simplexCache, TimeOfImpact._distanceInput); bool flag = distanceOutput.Distance <= 0f; if (flag) { break; } bool flag2 = distanceOutput.Distance < fP + y; if (flag2) { goto Block_3; } SeparationFunction.Set(ref simplexCache, input.ProxyA, ref sweepA, input.ProxyB, ref sweepB, fP2); bool flag3 = false; FP fP3 = tMax; int num2 = 0; while (true) { int indexA; int indexB; FP x2 = SeparationFunction.FindMinSeparation(out indexA, out indexB, fP3); bool flag4 = x2 > fP + y; if (flag4) { goto Block_4; } bool flag5 = x2 > fP - y; if (flag5) { goto Block_5; } FP fP4 = SeparationFunction.Evaluate(indexA, indexB, fP2); bool flag6 = fP4 < fP - y; if (flag6) { goto Block_6; } bool flag7 = fP4 <= fP + y; if (flag7) { goto Block_7; } int num3 = 0; FP fP5 = fP2; FP fP6 = fP3; FP fP7; bool flag11; do { bool flag8 = (num3 & 1) != 0; if (flag8) { fP7 = fP5 + (fP - fP4) * (fP6 - fP5) / (x2 - fP4); } else { fP7 = 0.5f * (fP5 + fP6); } num3++; FP fP8 = SeparationFunction.Evaluate(indexA, indexB, fP7); bool flag9 = FP.Abs(fP8 - fP) < y; if (flag9) { goto Block_9; } bool flag10 = fP8 > fP; if (flag10) { fP5 = fP7; fP4 = fP8; } else { fP6 = fP7; x2 = fP8; } flag11 = (num3 == 50); }while (!flag11); IL_373: num2++; bool flag12 = num2 == Settings.MaxPolygonVertices; if (flag12) { break; } continue; Block_9: fP3 = fP7; goto IL_373; } IL_396: num++; bool flag13 = flag3; if (flag13) { goto Block_13; } bool flag14 = num == 20; if (flag14) { goto Block_14; } continue; Block_4: output.State = TOIOutputState.Seperated; output.T = tMax; flag3 = true; goto IL_396; Block_5: fP2 = fP3; goto IL_396; Block_6: output.State = TOIOutputState.Failed; output.T = fP2; flag3 = true; goto IL_396; Block_7: output.State = TOIOutputState.Touching; output.T = fP2; flag3 = true; goto IL_396; } output.State = TOIOutputState.Overlapped; output.T = 0f; return; Block_3: output.State = TOIOutputState.Touching; output.T = fP2; Block_13: return; Block_14: output.State = TOIOutputState.Failed; output.T = fP2; }
/// <summary> /// Compute the upper bound on time before two shapes penetrate. Time is represented as /// a fraction between [0,tMax]. This uses a swept separating axis and may miss some intermediate, /// non-tunneling collision. If you change the time interval, you should call this function /// again. /// Note: use Distance() to compute the contact point and normal at the time of impact. /// </summary> /// <param name="output">The output.</param> /// <param name="input">The input.</param> public static void CalculateTimeOfImpact(out TOIOutput output, TOIInput input) { if (Settings.EnableDiagnostics) //FPE: We only gather diagnostics when enabled { ++TOICalls; } output = new TOIOutput(); output.State = TOIOutputState.Unknown; output.T = input.TMax; Sweep sweepA = input.SweepA; Sweep sweepB = input.SweepB; // Large rotations can make the root finder fail, so we normalize the // sweep angles. sweepA.Normalize(); sweepB.Normalize(); FP tMax = input.TMax; FP totalRadius = input.ProxyA.Radius + input.ProxyB.Radius; FP target = TrueSync.TSMath.Max(Settings.LinearSlop, totalRadius - 3.0f * Settings.LinearSlop); FP tolerance = 0.25f * Settings.LinearSlop; Debug.Assert(target > tolerance); FP t1 = 0.0f; const int k_maxIterations = 20; int iter = 0; // Prepare input for distance query. _distanceInput = _distanceInput ?? new DistanceInput(); _distanceInput.ProxyA = input.ProxyA; _distanceInput.ProxyB = input.ProxyB; _distanceInput.UseRadii = false; // The outer loop progressively attempts to compute new separating axes. // This loop terminates when an axis is repeated (no progress is made). for (; ;) { Transform xfA, xfB; sweepA.GetTransform(out xfA, t1); sweepB.GetTransform(out xfB, t1); // Get the distance between shapes. We can also use the results // to get a separating axis. _distanceInput.TransformA = xfA; _distanceInput.TransformB = xfB; DistanceOutput distanceOutput; SimplexCache cache; Distance.ComputeDistance(out distanceOutput, out cache, _distanceInput); // If the shapes are overlapped, we give up on continuous collision. if (distanceOutput.Distance <= 0.0f) { // Failure! output.State = TOIOutputState.Overlapped; output.T = 0.0f; break; } if (distanceOutput.Distance < target + tolerance) { // Victory! output.State = TOIOutputState.Touching; output.T = t1; break; } SeparationFunction.Set(ref cache, input.ProxyA, ref sweepA, input.ProxyB, ref sweepB, t1); // Compute the TOI on the separating axis. We do this by successively // resolving the deepest point. This loop is bounded by the number of vertices. bool done = false; FP t2 = tMax; int pushBackIter = 0; for (; ;) { // Find the deepest point at t2. Store the witness point indices. int indexA, indexB; FP s2 = SeparationFunction.FindMinSeparation(out indexA, out indexB, t2); // Is the final configuration separated? if (s2 > target + tolerance) { // Victory! output.State = TOIOutputState.Seperated; output.T = tMax; done = true; break; } // Has the separation reached tolerance? if (s2 > target - tolerance) { // Advance the sweeps t1 = t2; break; } // Compute the initial separation of the witness points. FP s1 = SeparationFunction.Evaluate(indexA, indexB, t1); // Check for initial overlap. This might happen if the root finder // runs out of iterations. if (s1 < target - tolerance) { output.State = TOIOutputState.Failed; output.T = t1; done = true; break; } // Check for touching if (s1 <= target + tolerance) { // Victory! t1 should hold the TOI (could be 0.0). output.State = TOIOutputState.Touching; output.T = t1; done = true; break; } // Compute 1D root of: f(x) - target = 0 int rootIterCount = 0; FP a1 = t1, a2 = t2; for (; ;) { // Use a mix of the secant rule and bisection. FP t; if ((rootIterCount & 1) != 0) { // Secant rule to improve convergence. t = a1 + (target - s1) * (a2 - a1) / (s2 - s1); } else { // Bisection to guarantee progress. t = 0.5f * (a1 + a2); } ++rootIterCount; if (Settings.EnableDiagnostics) //FPE: We only gather diagnostics when enabled { ++TOIRootIters; } FP s = SeparationFunction.Evaluate(indexA, indexB, t); if (FP.Abs(s - target) < tolerance) { // t2 holds a tentative value for t1 t2 = t; break; } // Ensure we continue to bracket the root. if (s > target) { a1 = t; s1 = s; } else { a2 = t; s2 = s; } if (rootIterCount == 50) { break; } } if (Settings.EnableDiagnostics) //FPE: We only gather diagnostics when enabled { TOIMaxRootIters = Math.Max(TOIMaxRootIters, rootIterCount); } ++pushBackIter; if (pushBackIter == Settings.MaxPolygonVertices) { break; } } ++iter; if (Settings.EnableDiagnostics) //FPE: We only gather diagnostics when enabled { ++TOIIters; } if (done) { break; } if (iter == k_maxIterations) { // Root finder got stuck. Semi-victory. output.State = TOIOutputState.Failed; output.T = t1; break; } } if (Settings.EnableDiagnostics) //FPE: We only gather diagnostics when enabled { TOIMaxIters = Math.Max(TOIMaxIters, iter); } }