BEPUphysics

Code: Select all

        public void Setup(Entity e, Vector3 grabLocation)
        {
            Entity = e;

            // Get the original entity properties that will need to be changed for this GrabSpring to function correctly
            isActive = Entity.IsActive;
            isAffectedByGravity = Entity.IsAffectedByGravity;
            isEntityDynamic = Entity.IsDynamic;
            originalEntityCollisonRule = Entity.CollisionInformation.CollisionRules.Personal;

            // Now change those properties so that the entity can be manipulated by the 'GrabSpring' in the desired manner

            // Make sure that the grabbed entity is active so it can be moved by the 'GrabSpring' if the simulation is paused
            Entity.IsActive = true;
            
            if (!isEntityDynamic)
            {
                Entity.BecomeDynamic(1f);
            }

            // Must be disabled AFTER becoming dynamic
            Entity.IsAffectedByGravity = false;

            // Can I assign a rule to this entity's collision pairs?
            // This way the other object in the collision pair will also react in the same way as this object for that particular collision.
            if (!(Entity.CollisionInformation.Tag is EntityAttractor))
            {
                Entity.CollisionInformation.CollisionRules.Personal = CollisionRule.NoBroadPhase;
            }

            LocalOffset = Vector3.Transform(grabLocation - e.Position, Quaternion.Conjugate(e.Orientation));

            GrabbedOrientation = e.Orientation;
            GoalPosition = grabLocation;

            angularMotor.Settings.Servo.Goal = e.Orientation;
            angularMotor.Settings.Servo.SpringSettings.StiffnessConstant = 60000f * Entity.Mass;
            angularMotor.Settings.Servo.SpringSettings.DampingConstant = 900f * Entity.Mass;
            angularMotor.Settings.MaximumForce = 10000f * Entity.Mass;
            angularMotor.Settings.VelocityMotor.Softness = .1f / e.Mass;

            // The stiffness, damping, and maximum force could be assigned during setup if the motor
            // needs to behave similarly for entities of varying masses.  
            // When using a fixed configuration, the grabspring will behave weakly when trying to move extremely heavy objects,
            // while staying very responsive for sufficiently light objects.
            linearMotor.Settings.Servo.SpringSettings.StiffnessConstant = 60000f * Entity.Mass;
            linearMotor.Settings.Servo.SpringSettings.DampingConstant = 900f * Entity.Mass;

            // An unlimited motor will gladly push the entity through other objects.
            // Putting a limit on the strength of the motor will prevent it from doing so.
            linearMotor.Settings.MaximumForce = 10000f * Entity.Mass;

            linearMotor.IsActive = grabSpringMode == GrabSpringMode.Rotation ? false : true;
        }

Code: Select all

        private void PauseSimulation()
        {
            for (int i = 0; i < space.Entities.Count; ++i)
            {
                space.Entities[i].IsActive = false;
            }

            for (int i = 0; i < entityAttractors.Count; ++i)
            {
                // Force fields are not allow to wake any object up when the simulation is paused
                entityAttractors[i].GravitationalField.ForceWakeUp = false;
            }
        }

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        public void Release()
        {
            if (!isEntityDynamic)
            {
                Entity.BecomeKinematic();
            }

            Entity.IsActive = isActive;                                              // false has no effect?
            Entity.IsAffectedByGravity = isAffectedByGravity;

            // Reset the entity's collision rule back to its original state
            Entity.CollisionInformation.CollisionRules.Personal = originalEntityCollisonRule;

            if (game.IsPaused)
            {
                // Remove all forces acting on the entity so it doesn't move in last direction of grabber after unpausing
                Entity.AngularMomentum = Vector3.Zero;
                Entity.AngularVelocity = Vector3.Zero;
                Entity.LinearMomentum = Vector3.Zero;
                Entity.LinearVelocity = Vector3.Zero;
            }

            Entity = null;
        }

Code: Select all

        private void PauseSimulation()
        {
            for (int i = 0; i < space.Entities.Count; ++i)
            {
                space.Entities[i].IsActive = false;
            }

            if (gui.GrabSpring.Entity != null)
            {
                gui.GrabSpring.Entity.IsActive = true;
            }

            for (int i = 0; i < entityAttractors.Count; ++i)
            {
                // Force fields are not allow to wake any object up when the simulation is paused
                entityAttractors[i].GravitationalField.ForceWakeUp = false;
            }
        }