Пример #1
0
        void IForceUpdateable.UpdateForForces(float dt)
        {
            //Linear velocity
            if (IsAffectedByGravity)
            {
                Vector3.Add(ref forceUpdater.gravityDt, ref linearVelocity, out linearVelocity);
            }

            //Boost damping at very low velocities.  This is a strong stabilizer; removes a ton of energy from the system.
            if (activityInformation.DeactivationManager.useStabilization && activityInformation.allowStabilization &&
                (activityInformation.isSlowing || activityInformation.velocityTimeBelowLimit > activityInformation.DeactivationManager.lowVelocityTimeMinimum))
            {
                float energy = linearVelocity.LengthSquared + angularVelocity.LengthSquared;
                if (energy < activityInformation.DeactivationManager.velocityLowerLimitSquared)
                {
                    float boost = 1 - (float)(Math.Sqrt(energy) / (2f * activityInformation.DeactivationManager.velocityLowerLimit));
                    ModifyAngularDamping(boost);
                    ModifyLinearDamping(boost);
                }
            }

            //Damping
            float linear = LinearDamping + linearDampingBoost;

            if (linear > 0)
            {
                Vector3.Multiply(ref linearVelocity, (float)Math.Pow(MathHelper.Clamp(1 - linear, 0, 1), dt), out linearVelocity);
            }
            //When applying angular damping, the momentum or velocity is damped depending on the conservation setting.
            float angular = AngularDamping + angularDampingBoost;

            if (angular > 0)
            {
#if CONSERVE
                Vector3.Multiply(ref angularMomentum, (float)Math.Pow(MathHelper.Clamp(1 - angular, 0, 1), dt), out angularMomentum);
#else
                Vector3.Multiply(ref angularVelocity, (float)Math.Pow(MathHelper.Clamp(1 - angular, 0, 1), dt), out angularVelocity);
#endif
            }

            linearDampingBoost  = 0;
            angularDampingBoost = 0;

            //Update world inertia tensors.
            Matrix3x3 multiplied;
            Matrix3x3.MultiplyTransposed(ref orientationMatrix4, ref localInertiaTensorInverse, out multiplied);
            Matrix3x3.Multiply(ref multiplied, ref orientationMatrix4, out inertiaTensorInverse);
            Matrix3x3.MultiplyTransposed(ref orientationMatrix4, ref localInertiaTensor, out multiplied);
            Matrix3x3.Multiply(ref multiplied, ref orientationMatrix4, out inertiaTensor);

#if CONSERVE
            //Update angular velocity.
            //Note that this doesn't play nice with singular inertia tensors.
            //Locked tensors result in zero angular velocity.
            Matrix3x3.Transform(ref angularMomentum, ref inertiaTensorInverse, out angularVelocity);
            MathChecker.Validate(angularMomentum);
#endif
            MathChecker.Validate(linearVelocity);
            MathChecker.Validate(angularVelocity);
        }
Пример #2
0
        void IPositionUpdateable.PreUpdatePosition(float dt)
        {
            Vector3 increment;

            Vector3.Multiply(ref angularVelocity, dt * .5f, out increment);
            var multiplier = new Quaternion(increment.X, increment.Y, increment.Z, 0);

            Quaternion.Multiply(ref multiplier, ref orientation, out multiplier);
            Quaternion.Add(ref orientation, ref multiplier, out orientation);
            orientation.Normalize();

            Matrix3x3.CreateFromQuaternion(ref orientation, out orientationMatrix4);

            //Only do the linear motion if this object doesn't obey CCD.
            if (PositionUpdateMode == PositionUpdateMode.Discrete)
            {
                Vector3.Multiply(ref linearVelocity, dt, out increment);
                Vector3.Add(ref position, ref increment, out position);

                collisionInformation.UpdateWorldTransform(ref position, ref orientation);
                //The position update is complete if this is a discretely updated object.
                if (PositionUpdated != null)
                {
                    PositionUpdated(this);
                }
            }

            MathChecker.Validate(linearVelocity);
            MathChecker.Validate(angularVelocity);
            MathChecker.Validate(position);
            MathChecker.Validate(orientation);
#if CONSERVE
            MathChecker.Validate(angularMomentum);
#endif
        }
Пример #3
0
 //These methods are very direct and quick.  They don't activate the object or anything.
 /// <summary>
 /// Applies a linear velocity change to the entity using the given impulse.
 /// This method does not wake up the object or perform any other nonessential operation;
 /// it is meant to be used for performance-sensitive constraint solving.
 /// Consider equivalently adding to the LinearMomentum property for convenience instead.
 /// </summary>
 /// <param name="impulse">Impulse to apply.</param>
 public void ApplyLinearImpulse(ref Vector3 impulse)
 {
     linearVelocity.X += impulse.X * inverseMass;
     linearVelocity.Y += impulse.Y * inverseMass;
     linearVelocity.Z += impulse.Z * inverseMass;
     MathChecker.Validate(linearVelocity);
 }
Пример #4
0
        /// <summary>
        /// Applies an angular velocity change to the entity using the given impulse.
        /// This method does not wake up the object or perform any other nonessential operation;
        /// it is meant to be used for performance-sensitive constraint solving.
        /// Consider equivalently adding to the AngularMomentum property for convenience instead.
        /// </summary>
        /// <param name="impulse">Impulse to apply.</param>
        public void ApplyAngularImpulse(ref Vector3 impulse)
        {
            //There's some room here for SIMD-friendliness.  However, since the phone doesn't accelerate non-XNA types, the Matrix3x3 operations don't gain much.
#if CONSERVE
            angularMomentum.X += impulse.X;
            angularMomentum.Y += impulse.Y;
            angularMomentum.Z += impulse.Z;
            angularVelocity.X  = angularMomentum.X * inertiaTensorInverse.M11 + angularMomentum.Y * inertiaTensorInverse.M21 + angularMomentum.Z * inertiaTensorInverse.M31;
            angularVelocity.Y  = angularMomentum.X * inertiaTensorInverse.M12 + angularMomentum.Y * inertiaTensorInverse.M22 + angularMomentum.Z * inertiaTensorInverse.M32;
            angularVelocity.Z  = angularMomentum.X * inertiaTensorInverse.M13 + angularMomentum.Y * inertiaTensorInverse.M23 + angularMomentum.Z * inertiaTensorInverse.M33;

            MathChecker.Validate(angularMomentum);
#else
            angularVelocity.X += impulse.X * inertiaTensorInverse.M11 + impulse.Y * inertiaTensorInverse.M21 + impulse.Z * inertiaTensorInverse.M31;
            angularVelocity.Y += impulse.X * inertiaTensorInverse.M12 + impulse.Y * inertiaTensorInverse.M22 + impulse.Z * inertiaTensorInverse.M32;
            angularVelocity.Z += impulse.X * inertiaTensorInverse.M13 + impulse.Y * inertiaTensorInverse.M23 + impulse.Z * inertiaTensorInverse.M33;
#endif

            MathChecker.Validate(angularVelocity);
        }
Пример #5
0
        void ICCDPositionUpdateable.UpdatePositionContinuously(float dt)
        {
            float minimumToi = 1;

            for (int i = 0; i < collisionInformation.pairs.Count; i++)
            {
                if (collisionInformation.pairs.Elements[i].timeOfImpact < minimumToi)
                {
                    minimumToi = collisionInformation.pairs.Elements[i].timeOfImpact;
                }
            }

            //The orientation was already updated by the PreUpdatePosition.
            //However, to be here, this object is not a discretely updated object.
            //That means we still need to update the linear motion.

            Vector3 increment;

            Vector3.Multiply(ref linearVelocity, dt * minimumToi, out increment);
            Vector3.Add(ref position, ref increment, out position);

            collisionInformation.UpdateWorldTransform(ref position, ref orientation);

            if (PositionUpdated != null)
            {
                PositionUpdated(this);
            }

            MathChecker.Validate(linearVelocity);
            MathChecker.Validate(angularVelocity);
            MathChecker.Validate(position);
            MathChecker.Validate(orientation);
#if CONSERVE
            MathChecker.Validate(angularMomentum);
#endif
        }