public void Fire()
{
var movementData = EntityManager.GetComponentData <PlungerMovementData>(Entity);
var velocityData = EntityManager.GetComponentData <PlungerVelocityData>(Entity);
var staticData = EntityManager.GetComponentData <PlungerStaticData>(Entity);
// check for an auto plunger
if (Item.Data.AutoPlunger)
{
// Auto Plunger - this models a "Launch Ball" button or a
// ROM-controlled launcher, rather than a player-operated
// spring plunger. In a physical machine, this would be
// implemented as a solenoid kicker, so the amount of force
// is constant (modulo some mechanical randomness). Simulate
// this by triggering a release from the maximum retracted
// position.
PlungerCommands.Fire(1f, ref velocityData, ref movementData, in staticData);
}
else
{
// Regular plunger - trigger a release from the current
// position, using the keyboard firing strength.
var pos = (movementData.Position - staticData.FrameEnd) / (staticData.FrameStart - staticData.FrameEnd);
PlungerCommands.Fire(pos, ref velocityData, ref movementData, in staticData);
}
EntityManager.SetComponentData(Entity, movementData);
EntityManager.SetComponentData(Entity, velocityData);
}
public void PullBack()
{
var movementData = EntityManager.GetComponentData <PlungerMovementData>(Entity);
var velocityData = EntityManager.GetComponentData <PlungerVelocityData>(Entity);
if (DoRetract)
{
PlungerCommands.PullBackAndRetract(Item.Data.SpeedPull, ref velocityData, ref movementData);
}
else
{
PlungerCommands.PullBack(Item.Data.SpeedPull, ref velocityData, ref movementData);
}
EntityManager.SetComponentData(Entity, movementData);
EntityManager.SetComponentData(Entity, velocityData);
}
protected override void OnUpdate()
{
var marker = PerfMarker;
Entities.ForEach((ref PlungerMovementData movementData, ref PlungerVelocityData velocityData,
in PlungerStaticData staticData) =>
{
marker.Begin();
// figure our current position in relative coordinates (0.0-1.0,
// where 0.0 is the maximum forward position and 1.0 is the
// maximum retracted position)
var pos = (movementData.Position - staticData.FrameEnd) / staticData.FrameLen;
// todo | If "mech plunger" is enabled, read the mechanical plunger
// todo | position; otherwise treat it as fixed at 0.
const float mech = 0f; //staticData.IsMechPlunger ? MechPlunger() : 0.0f;
// calculate the delta from the last reading
var dMech = velocityData.Mech0 - mech;
// Frame-to-frame mech movement threshold for detecting a release
// motion. 1.0 is the full range of travel, which corresponds
// to about 3" on a standard pinball plunger. We want to choose
// the value here so that it's faster than the player is likely
// to move the plunger manually, but slower than the plunger
// typically moves under spring power when released. It appears
// from observation that a real plunger moves at something on the
// order of 3 m/s. Figure the fastest USB update interval will
// be 10ms, typical is probably 25ms, and slowest is maybe 40ms;
// and figure the bracket speed range down to about 1 m/s. This
// gives us a distance per USB interval of from 25mm to 100mm.
// 25mm translates to .32 of our distance units (0.0-1.0 scale).
// The lower we make this, the more sensitive we'll be at
// detecting releases, but if we make it too low we might mistake
// manual movements for releases. In practice, it seems safe to
// lower it to about 0.2 - this doesn't seem to cause false
// positives and seems reliable at identifying actual releases.
const float releaseThreshold = 0.2f;
// note if we're acting as an auto plunger
var autoPlunger = staticData.IsAutoPlunger;
// check which forces are acting on us
if (movementData.FireTimer > 0)
{
// Fire mode. In this mode, we're moving freely under the spring
// forces at the speed we calculated when we initiated the release.
// Simply leave the speed unchanged.
//
// Decrement the release mode timer. The mode ends after the
// timeout elapses, even if the mech plunger hasn't actually
// come to rest. This ensures that we don't get stuck in this
// mode, and also allows us to sync up again with the real
// plunger after a respectable pause if the user is just
// moving it around a lot.
movementData.Speed = movementData.FireSpeed;
--movementData.FireTimer;
}
else if (velocityData.AutoFireTimer > 0)
{
// The Auto Fire timer is running. We start this timer when we
// send a synthetic KeyDown(Return) event to the script to simulate
// a Launch Ball event when the user pulls back and releases the
// mechanical plunger and we're operating as an auto plunger.
// When the timer reaches zero, we'll send the corresponding
// KeyUp event and cancel the timer.
if (--velocityData.AutoFireTimer == 0)
{
// todo event
// if (g_pplayer != 0) {
// g_pplayer->m_ptable->FireKeyEvent(DISPID_GameEvents_KeyUp, g_pplayer->m_rgKeys[ePlungerKey]);
// }
}
}
else if (autoPlunger && dMech > releaseThreshold)
{
// Release motion detected in Auto Plunger mode.
//
// If we're acting as an auto plunger, and the player performs
// a pull-and-release motion on the mechanical plunger, simulate
// a Launch Ball event.
//
// An Auto Plunger simulates a solenoid-driven ball launcher
// on a table like Medieval Madness. On this type of game,
// the original machine doesn't have a spring-loaded plunger.
// for the user to operate manually. The user-operated control
// is instead a button of some kind (the physical form varies
// quite a bit, from big round pushbuttons to gun triggers to
// levers to rotating knobs, but they all amount to momentary
// on/off switches in different guises). But on virtual
// cabinets, the mechanical plunger doesn't just magically
// disappear when you load Medieval Madness! So the idea here
// is that we can use a mech plunger to simulate a button.
// It's pretty simple and natural: you just perform the normal
// action that you're accustomed to doing with a plunger,
// namely pulling it back and letting it go. The software
// observes this gesture, and rather than trying to simulate
// the motion directly on the software plunger, we simply
// turn it into a synthetic Launch Ball keyboard event. This
// amounts to sending a KeyDown(Return) message to the script,
// followed a short time later by a KeyUp(Return). The script
// will then act exactly like it would if the user had actually
// pressed the Return key (or, equivalently on a cabinet, the
// Launch Ball button).
// Send a KeyDown(Return) to the table script. This
// will allow the script to set ROM switch levels or
// perform any other tasks it normally does when the
// actual Launch Ball button is pressed.
// todo event
// if (g_pplayer != 0) {
// g_pplayer->m_ptable->FireKeyEvent(DISPID_GameEvents_KeyDown, g_pplayer->m_rgKeys[ePlungerKey]);
// }
// start the timer to send the corresponding KeyUp in 100ms
velocityData.AutoFireTimer = 101;
}
else if (velocityData.PullForce != 0.0f)
{
// A "pull" force is in effect. This is a *simulated* pull, so
// it overrides the real physical plunger position.
//
// Simply update the model speed by applying the acceleration
// due to the pull force.
//
// Force = mass*acceleration -> a = F/m. Increase the speed
// by the acceleration. Technically we're calculating dv = a dt,
// but we can elide the elapsed time factor because it's
// effectively a constant that's implicitly folded into the
// pull force value.
movementData.Speed += velocityData.PullForce / Engine.VPT.Plunger.Plunger.PlungerMass;
if (!velocityData.AddRetractMotion)
{
// this is the normal PullBack branch
// if we're already at the maximum retracted position, stop
if (movementData.Position > staticData.FrameStart)
{
movementData.Speed = 0.0f;
movementData.Position = staticData.FrameStart;
}
// if we're already at the minimum retracted position, stop
if (movementData.Position < staticData.FrameEnd + staticData.RestPosition * staticData.FrameLen)
{
movementData.Speed = 0.0f;
movementData.Position = staticData.FrameEnd + staticData.RestPosition * staticData.FrameLen;
}
}
else
{
// this is the PullBackandRetract branch
// after reaching the max. position the plunger should retract until it reaches the min. position and then start again
// if we're already at the maximum retracted position, reverse
if (movementData.Position >= staticData.FrameStart && velocityData.PullForce > 0)
{
movementData.Speed = 0.0f;
movementData.Position = staticData.FrameStart;
velocityData.RetractWaitLoop++;
if (velocityData.RetractWaitLoop > 1000) // 1 sec, related to PHYSICS_STEPTIME
{
velocityData.PullForce = -velocityData.InitialSpeed;
movementData.Position = staticData.FrameStart;
movementData.RetractMotion = true;
velocityData.RetractWaitLoop = 0;
}
}
// if we're already at the minimum retracted position, start again
if (movementData.Position <= staticData.FrameEnd + staticData.RestPosition * staticData.FrameLen && velocityData.PullForce <= 0)
{
movementData.Speed = 0.0f;
velocityData.PullForce = velocityData.InitialSpeed;
movementData.Position = staticData.FrameEnd + staticData.RestPosition * staticData.FrameLen;
}
// reset retract motion indicator only after the rest position has been left, to avoid ball interactions
// use a linear pullback motion
if (movementData.Position > 1.0f + staticData.FrameEnd + staticData.RestPosition * staticData.FrameLen && velocityData.PullForce > 0)
{
movementData.RetractMotion = false;
movementData.Speed = 3.0f * velocityData.PullForce; // 3 = magic
}
}
}
else if (dMech > releaseThreshold)
{
// Normal mode, fast forward motion detected. Consider this
// to be a release event.
//
// The release motion of a physical plunger is much faster
// than our sampling rate can keep up with, so we can't just
// use the joystick readings directly. The problem is that a
// real plunger can shoot all the way forward, bounce all the
// way back, and shoot forward again in the time between two
// consecutive samples. A real plunger moves at around 3-5m/s,
// which translates to 3-5mm/ms, or 30-50mm per 10ms sampling
// period. The whole plunger travel distance is ~65mm.
// So in one reading, we can travel almost the whole range!
// This means that samples are effectively random during a
// release motion. We might happen to get lucky and have
// our sample timing align perfectly with a release, so that
// we get one reading at the retracted position just before
// a release and the very next reading at the full forward
// position. Or we might get unlikely and catch one reading
// halfway down the initial initial lunge and the next reading
// at the very apex of the bounce back - and if we took those
// two readings at face value, we'd be fooled into thinking
// the plunger was stationary at the halfway point!
//
// But there's hope. A real plunger's barrel spring is pretty
// inelastic, so the rebounds after a release damp out quickly.
// Observationally, each bounce bounces back to less than half
// of the previous one. So even with the worst-case aliasing,
// we can be confident that we'll see a declining trend in the
// samples during a release-bounce-bounce-bounce sequence.
//
// Our detection strategy is simply to consider any rapid
// forward motion to be a release. If we see the plunger move
// forward by more than the threshold distance, we'll consider
// it a release. See the comments above for how we chose the
// threshold value.
// Go back through the recent history to find the apex of the
// release. Our "threshold" calculation is basically attempting
// to measure the instantaneous speed of the plunger as the
// difference in position divided by the time interval. But
// the time interval is extremely imprecise, because joystick
// reports aren't synchronized to our clock. In practice the
// time between USB reports is in the 10-30ms range, which gives
// us a considerable range of error in calculating an instantaneous
// speed.
//
// So instead of relying on the instantaneous speed alone, now
// that we're pretty sure a release motion is under way, go back
// through our recent history to find out where it really
// started. Scan the history for monotonically ascending values,
// and take the highest one we find. That's probably where the
// user actually released the plunger.
var apex = velocityData.Mech0;
if (velocityData.Mech1 > apex)
{
apex = velocityData.Mech1;
if (velocityData.Mech2 > apex)
{
apex = velocityData.Mech2;
}
}
// trigger a release from the apex position
PlungerCommands.Fire(apex, ref velocityData, ref movementData, in staticData);
}
else
{
// Normal mode, and NOT firing the plunger. In this mode, we
// simply want to make the on-screen plunger sync up with the
// position of the physical plunger.
//
// This isn't as simple as just setting the software plunger's
// position to magically match that of the physical plunger. If
// we did that, we'd break the simulation by making the software
// plunger move at infinite speed. This wouldn't rip the fabric
// of space-time or anything that dire, but it *would* prevent
// the collision detection code from working properly.
//
// So instead, sync up the positions by setting the software
// plunger in motion on a course for syncing up with the
// physical plunger, as fast as we can while maintaining a
// realistic speed in the simulation.
// for a normal plunger, sync to the mech plunger; otherwise
// just go to the rest position
var target = autoPlunger ? staticData.RestPosition : mech;
// figure the current difference in positions
var error = target - pos;
// Model the software plunger as though it were connected to the
// mechanical plunger by a spring with spring constant 'mech
// strength'. The force from a stretched spring is -kx (spring
// constant times displacement); in this case, the displacement
// is the distance between the physical and virtual plunger tip
// positions ('error'). The force from an acceleration is ma,
// so the acceleration from the spring force is -kx/m. Apply
// this acceleration to the current plunger speed. While we're
// at it, apply some damping to the current speed to simulate
// friction.
//
// The 'normalize' factor is the table's normalization constant
// divided by 1300, for historical reasons. Old versions applied
// a 1/13 adjustment factor, which appears to have been empirically
// chosen to get the speed in the right range. The m_plungerNormalize
// factor has default value 100 in this version, so we need to
// divide it by 100 to get a multipler value.
//
// The 'dt' factor represents the amount of time that we're applying
// this acceleration. This is in "VP 9 physics frame" units, where
// 1.0 equals the amount of real time in one VP 9 physics frame.
// The other normalization factors were originally chosen for VP 9
// timing, so we need to adjust for the new VP 10 time base. VP 10
// runs physics frames at roughly 10x the rate of VP 9, so the time
// per frame is about 1/10 the VP 9 time.
const float plungerFriction = 0.95f;
const float normalize = Engine.VPT.Plunger.Plunger.PlungerNormalize / 13.0f / 100.0f;
const float dt = 0.1f;
movementData.Speed *= plungerFriction;
movementData.Speed += error * staticData.FrameLen * velocityData.MechStrength / Engine.VPT.Plunger.Plunger.PlungerMass * normalize * dt;
// add any reverse impulse to the result
movementData.Speed += movementData.ReverseImpulse;
}
// cancel any reverse impulse
movementData.ReverseImpulse = 0.0f;
// Shift the current mech reading into the history list, if it's
// different from the last reading. Only keep distinct readings;
// the physics loop tends to run faster than the USB reporting
// rate, so we might see the same USB report several times here.
if (mech != velocityData.Mech0)
{
velocityData.Mech2 = velocityData.Mech1;
velocityData.Mech1 = velocityData.Mech0;
velocityData.Mech0 = mech;
}
marker.End();
}).Run();
}