additional catchup mechanic by lowering maxspeed

core/src/com/agateau/pixelwheels/GamePlay.java

@@ -45,13 +45,15 @@ public class GamePlay {
 
     public int viewportWidth = 60;
 
-    public int turboStrength = 200;
+    public int turboStrength = 70;
     public float turboDuration = 0.5f;
 
     // When an AI is better ranked than a player, set its max speed to this percent of the best max
     // speed
     public float aiSpeedLimiter = 0.8f;
 
+    public float catchupFactor = 20;
+
     public boolean oneLapOnly = false;
     public boolean freeCamera = false;
 

core/src/com/agateau/pixelwheels/racer/Vehicle.java

@@ -79,6 +79,7 @@ public static class WheelInfo {
     private boolean mStopped = false;
     private Material mMaterial = Material.ROAD;
     private float mSpeedLimiter = 1f;
+    private float mMaxSpeed = GamePlay.instance.maxSpeed;
     private boolean mFlying = false;
 
     private Probe mProbe = null;
@@ -255,6 +256,14 @@ public void setSpeedLimiter(float speedLimiter) {
         mSpeedLimiter = speedLimiter;
     }
 
+    public float getMaxSpeed() {
+        return mMaxSpeed;
+    }
+
+    public void setMaxSpeed(float maxSpeed) {
+        mMaxSpeed = maxSpeed;
+    }
+
     /** Returns the angle the car is facing */
     public float getAngle() {
         return AgcMathUtils.normalizeAngle(mBody.getAngle() * MathUtils.radiansToDegrees);
@@ -381,7 +390,7 @@ private void applyPilotCommands() {
         float steerAngle = computeSteerAngle() * MathUtils.degRad;
         for (WheelInfo info : mWheels) {
             float angle = info.steeringFactor * steerAngle;
-            info.wheel.adjustSpeed(speedDelta);
+            info.wheel.adjustSpeed(speedDelta, mMaxSpeed);
             info.joint.setLimits(angle, angle);
         }
     }

core/src/com/agateau/pixelwheels/racer/Wheel.java

@@ -183,14 +183,13 @@ public float getGroundSpeed() {
         return mMaterial.getSpeed();
     }
 
-    public void adjustSpeed(float amount) {
+    public void adjustSpeed(float amount, float maxSpeed) {
         if (amount == 0) {
             return;
         }
         final float currentSpeed = mBody.getLinearVelocity().len() * Box2DUtils.MS_TO_KMH;
 
-        final float limit =
-                1 - 0.2f * Interpolation.sineOut.apply(currentSpeed / GamePlay.instance.maxSpeed);
+        final float limit = 1 - 0.2f * Interpolation.sineOut.apply(currentSpeed / maxSpeed);
         amount *= limit;
 
         float force = mMaxDrivingForce * amount;

core/src/com/agateau/pixelwheels/racescreen/GameWorldImpl.java

@@ -20,6 +20,7 @@
 
 import com.agateau.pixelwheels.Assets;
 import com.agateau.pixelwheels.Constants;
+import com.agateau.pixelwheels.GamePlay;
 import com.agateau.pixelwheels.GameWorld;
 import com.agateau.pixelwheels.PwGame;
 import com.agateau.pixelwheels.bonus.Bonus;
@@ -183,6 +184,34 @@ public GameStats getGameStats() {
 
     @Override
     public void act(float delta) {
+        // lower maxSpeed of racers ahead of another, propotional to the distance between them
+        final int distancePerLap = mTrack.getLapPositionTable().getSectionCount();
+        final float catchupRatio = GamePlay.instance.catchupFactor / distancePerLap;
+        mRacers.sort(sRacerComparator);
+        Racer racerBehind = null;
+        for (int i = mRacers.size - 1; i >= 0; i--) {
+            final Racer racer = mRacers.get(i);
+            if (racer.getLapPositionComponent().hasFinishedRace()) {
+                break;
+            }
+            if (racerBehind == null) {
+                racer.getVehicle().setMaxSpeed(GamePlay.instance.maxSpeed);
+            } else {
+                final LapPositionComponent p1 = racer.getLapPositionComponent();
+                final LapPositionComponent p2 = racerBehind.getLapPositionComponent();
+                final float ddiff =
+                        (p1.getLapCount() - p2.getLapCount()) * distancePerLap
+                                + p1.getLapDistance()
+                                - p2.getLapDistance();
+                assert ddiff >= 0;
+                racer.getVehicle()
+                        .setMaxSpeed(
+                                racerBehind.getVehicle().getMaxSpeed()
+                                        / (1 + ddiff * catchupRatio));
+            }
+            racerBehind = racer;
+        }
+
         // fixed time step
         // max frame time to avoid spiral of death (on slow devices)
         float frameTime = Math.min(delta, 0.25f);
@@ -214,7 +243,6 @@ public void act(float delta) {
         }
 
         if (haveAllRacersFinished()) {
-            mRacers.sort(sRacerComparator);
             setState(GameWorld.State.FINISHED);
         }
     }