BulletSim: reorganize motor code a little to pull together common functions.

Add BSFMotor.

OpenSim/Region/Physics/BulletSPlugin/BSMotors.cs

@@ -58,14 +58,11 @@ public abstract class BSMotor
     protected void MDetailLog(string msg, params Object[] parms)
     {
         if (PhysicsScene != null)
-        {
-            if (PhysicsScene.VehicleLoggingEnabled)
         {
             PhysicsScene.DetailLog(msg, parms);
         }
     }
 }
-}
 
 // Motor which moves CurrentValue to TargetValue over TimeScale seconds.
 // The TargetValue decays in TargetValueDecayTimeScale and
@@ -100,10 +97,13 @@ public class BSVMotor : BSMotor
     public virtual Vector3 CurrentValue { get; protected set; }
     public virtual Vector3 LastError { get; protected set; }
 
-    public virtual bool ErrorIsZero
+    public virtual bool ErrorIsZero()
-    { get {
+    {
-        return (LastError == Vector3.Zero || LastError.LengthSquared() <= ErrorZeroThreshold);
+        return ErrorIsZero(LastError);
     }
+    public virtual bool ErrorIsZero(Vector3 err)
+    { 
+        return (err == Vector3.Zero || err.ApproxEquals(Vector3.Zero, ErrorZeroThreshold));
     }
 
     public BSVMotor(string useName)
@@ -148,7 +148,7 @@ public class BSVMotor : BSMotor
 
         Vector3 correction = Vector3.Zero;
         Vector3 error = TargetValue - CurrentValue;
-        if (!error.ApproxEquals(Vector3.Zero, ErrorZeroThreshold))
+        if (!ErrorIsZero(error))
         {
             correction = Step(timeStep, error);
 
@@ -200,7 +200,7 @@ public class BSVMotor : BSMotor
 
         LastError = error;
         Vector3 returnCorrection = Vector3.Zero;
-        if (!error.ApproxEquals(Vector3.Zero, ErrorZeroThreshold))
+        if (!ErrorIsZero())
         {
             // correction =  error / secondsItShouldTakeToCorrect
             Vector3 correctionAmount;
@@ -246,32 +246,139 @@ public class BSVMotor : BSMotor
     }
 }
 
+// ============================================================================
+// ============================================================================
 public class BSFMotor : BSMotor
 {
-    public float TimeScale { get; set; }
+    public virtual float TimeScale { get; set; }
-    public float DecayTimeScale { get; set; }
+    public virtual float TargetValueDecayTimeScale { get; set; }
-    public float Friction { get; set; }
+    public virtual float FrictionTimescale { get; set; }
-    public float Efficiency { get; set; }
+    public virtual float Efficiency { get; set; }
 
-    public float Target { get; private set; }
+    public virtual float ErrorZeroThreshold { get; set; }
-    public float CurrentValue { get; private set; }
+
+    public virtual float TargetValue { get; protected set; }
+    public virtual float CurrentValue { get; protected set; }
+    public virtual float LastError { get; protected set; }
+
+    public virtual bool ErrorIsZero()
+    {
+        return ErrorIsZero(LastError);
+    }
+    public virtual bool ErrorIsZero(float err)
+    { 
+        return (err >= -ErrorZeroThreshold && err <= ErrorZeroThreshold);
+    }
 
     public BSFMotor(string useName, float timeScale, float decayTimescale, float friction, float efficiency)
         : base(useName)
     {
+        TimeScale = TargetValueDecayTimeScale = BSMotor.Infinite;
+        Efficiency = 1f;
+        FrictionTimescale = BSMotor.Infinite;
+        CurrentValue = TargetValue = 0f;
+        ErrorZeroThreshold = 0.01f;
     }
-    public void SetCurrent(float target)
+    public void SetCurrent(float current)
     {
+        CurrentValue = current;
     }
     public void SetTarget(float target)
     {
+        TargetValue = target;
     }
-    public virtual float Step(float timeStep)
+    public override void Zero()
     {
-        return 0f;
+        base.Zero();
-    }
+        CurrentValue = TargetValue = 0f;
     }
 
+    public virtual float Step(float timeStep)
+    {
+        if (!Enabled) return TargetValue;
+
+        float origTarget = TargetValue;       // DEBUG
+        float origCurrVal = CurrentValue;     // DEBUG
+
+        float correction = 0f;
+        float error = TargetValue - CurrentValue;
+        if (!ErrorIsZero(error))
+        {
+            correction = Step(timeStep, error);
+
+            CurrentValue += correction;
+
+            // The desired value reduces to zero which also reduces the difference with current.
+            // If the decay time is infinite, don't decay at all.
+            float decayFactor = 0f;
+            if (TargetValueDecayTimeScale != BSMotor.Infinite)
+            {
+                decayFactor = (1.0f / TargetValueDecayTimeScale) * timeStep;
+                TargetValue *= (1f - decayFactor);
+            }
+
+            // The amount we can correct the error is reduced by the friction
+            float frictionFactor = 0f;
+            if (FrictionTimescale != BSMotor.Infinite)
+            {
+                // frictionFactor = (Vector3.One / FrictionTimescale) * timeStep;
+                // Individual friction components can be 'infinite' so compute each separately.
+                frictionFactor = 1f / FrictionTimescale;
+                frictionFactor *= timeStep;
+                CurrentValue *= (1f - frictionFactor);
+            }
+
+            MDetailLog("{0},  BSFMotor.Step,nonZero,{1},origCurr={2},origTarget={3},timeStep={4},err={5},corr={6}",
+                                BSScene.DetailLogZero, UseName, origCurrVal, origTarget,
+                                timeStep, error, correction);
+            MDetailLog("{0},  BSFMotor.Step,nonZero,{1},tgtDecayTS={2},decayFact={3},frictTS={4},frictFact={5},tgt={6},curr={7}",
+                                BSScene.DetailLogZero, UseName,
+                                TargetValueDecayTimeScale, decayFactor, FrictionTimescale, frictionFactor,
+                                TargetValue, CurrentValue);
+        }
+        else
+        {
+            // Difference between what we have and target is small. Motor is done.
+            CurrentValue = TargetValue;
+            MDetailLog("{0},  BSFMotor.Step,zero,{1},origTgt={2},origCurr={3},ret={4}",
+                        BSScene.DetailLogZero, UseName, origCurrVal, origTarget, CurrentValue);
+        }
+
+        return CurrentValue;
+    }
+
+    public virtual float Step(float timeStep, float error)
+    {
+        if (!Enabled) return 0f;
+
+        LastError = error;
+        float returnCorrection = 0f;
+        if (!ErrorIsZero())
+        {
+            // correction =  error / secondsItShouldTakeToCorrect
+            float correctionAmount;
+            if (TimeScale == 0f || TimeScale == BSMotor.Infinite)
+                correctionAmount = error * timeStep;
+            else
+                correctionAmount = error / TimeScale * timeStep;
+
+            returnCorrection = correctionAmount;
+            MDetailLog("{0},  BSFMotor.Step,nonZero,{1},timeStep={2},timeScale={3},err={4},corr={5}",
+                                    BSScene.DetailLogZero, UseName, timeStep, TimeScale, error, correctionAmount);
+        }
+        return returnCorrection;
+    }
+
+    public override string ToString()
+    {
+        return String.Format("<{0},curr={1},targ={2},lastErr={3},decayTS={4},frictTS={5}>",
+            UseName, CurrentValue, TargetValue, LastError, TargetValueDecayTimeScale, FrictionTimescale);
+    }
+
+}
+
+// ============================================================================
+// ============================================================================
 // Proportional, Integral, Derivitive Motor
 // Good description at http://www.answers.com/topic/pid-controller . Includes processes for choosing p, i and d factors.
 public class BSPIDVMotor : BSVMotor
@@ -319,6 +426,7 @@ public class BSPIDVMotor : BSVMotor
             proportionFactor = new Vector3(factor, factor, factor);
             integralFactor = new Vector3(factor, factor, factor);
             derivFactor = new Vector3(factor, factor, factor);
+            MDetailLog("{0},BSPIDVMotor.setEfficiency,eff={1},factor={2}", BSScene.DetailLogZero, Efficiency, factor);
         }
     }
 
@@ -341,6 +449,9 @@ public class BSPIDVMotor : BSVMotor
                         + derivFactor * derivFactor
                         );
 
+        MDetailLog("{0},BSPIDVMotor.step,ts={1},err={2},runnInt={3},derivFact={4},ret={5}",
+                        BSScene.DetailLogZero, timeStep, error, RunningIntegration, derivFactor, ret);
+
         return ret;
     }
 }