diff --git a/src/simulator/simulator.physics.cpp b/src/simulator/simulator.physics.cpp index bf3f6084e..0cc1acdca 100644 --- a/src/simulator/simulator.physics.cpp +++ b/src/simulator/simulator.physics.cpp @@ -2,6 +2,15 @@ namespace mrover { + // Determines the timestep for the physics update. + // Need a relatively high frequency to achive a stable simulation. + constexpr unsigned int PHYSICS_UPDATE_HZ = 120; + // Set to a very high value, so that if the computer can not keep up the above in realtime, it slows down instead of dropping frames. + // In a video game we do not want this behavior but this is robotics so we have to be deterministic. + // See: https://stackoverflow.com/questions/12778229/what-does-step-mean-in-stepsimulation-and-what-do-its-parameters-mean-in-bulle + // Important formula that needs to hold true to avoid dropping: timeStep < maxSubSteps * fixedTimeStep + constexpr int MAX_SUB_STEPS = 1024; + auto btTransformToSe3(btTransform const& transform) -> SE3d { btVector3 const& p = transform.getOrigin(); btQuaternion const& q = transform.getRotation(); @@ -21,8 +30,8 @@ namespace mrover { mBroadphase = std::make_unique(mOverlappingPairCache.get()); - // mSolver = std::make_unique(new btDantzigSolver{}); - mSolver = std::make_unique(); + mSolver = std::make_unique(new btDantzigSolver{}); + // mSolver = std::make_unique(); mDynamicsWorld = std::make_unique(mDispatcher.get(), mBroadphase.get(), mSolver.get(), mCollisionConfig.get()); // mDynamicsWorld->getSolverInfo().m_minimumSolverBatchSize = 1; @@ -43,25 +52,20 @@ namespace mrover { } } - // TODO(quintin): clean this up - int maxSubSteps = 0; float updateDuration = std::clamp(std::chrono::duration_cast>(dt).count(), 0.0f, 0.1f); - [[maybe_unused]] int simStepCount = mDynamicsWorld->stepSimulation(updateDuration, maxSubSteps, 1 / 120.0f); - - // // TODO(quintin): Figure out why this fails - // if (auto* mlcpSolver = dynamic_cast(mDynamicsWorld->getConstraintSolver())) { - // // if (int fallbackCount = mlcpSolver->getNumFallbacks()) { - // // NODELET_WARN_STREAM_THROTTLE(1, std::format("MLCP solver failed {} times", fallbackCount)); - // // } - // mlcpSolver->setNumFallbacks(0); - // } - - // if (simStepCount) { - // if (simStepCount > maxSubSteps) { - // int droppedSteps = simStepCount - maxSubSteps; - // NODELET_WARN_STREAM(std::format("Dropped {} simulation steps out of {}", droppedSteps, simStepCount)); - // } - // } + int simStepCount = mDynamicsWorld->stepSimulation(updateDuration, MAX_SUB_STEPS, 1.f / PHYSICS_UPDATE_HZ); + + if (auto* mlcpSolver = dynamic_cast(mDynamicsWorld->getConstraintSolver())) { + if (int fallbackCount = mlcpSolver->getNumFallbacks()) { + NODELET_WARN_STREAM_THROTTLE(1, std::format("MLCP solver failed {} times", fallbackCount)); + } + mlcpSolver->setNumFallbacks(0); + } + + if (!mHeadless && simStepCount && simStepCount > MAX_SUB_STEPS) { + int droppedSteps = simStepCount - MAX_SUB_STEPS; + NODELET_ERROR_STREAM(std::format("Dropped {} simulation steps out of {}! This should never happen unless you have a literal potatoe of a computer", droppedSteps, simStepCount)); + } linksToTfUpdate();