Fly changes

src/main/java/dev/brighten/ac/check/impl/fly/FlyA.java

@@ -9,8 +9,6 @@ import dev.brighten.ac.packet.ProtocolVersion;
 import dev.brighten.ac.packet.wrapper.in.WPacketPlayInFlying;
 import dev.brighten.ac.utils.MathUtils;
 import dev.brighten.ac.utils.MovementUtils;
-import dev.brighten.ac.utils.timer.Timer;
-import dev.brighten.ac.utils.timer.impl.MillisTimer;
 
 @CheckData(name = "Fly (A)", type = CheckType.MOVEMENT)
 public class FlyA extends Check {
@@ -19,42 +17,58 @@ public class FlyA extends Check {
         super(player);
     }
 
-    private Timer lastPos = new MillisTimer();
     private float buffer;
-    private static double mult = 0.98f;
+
+    //our predicted value using client movement maths.
+    private double predictedValue = 0.0;
+    //how much will the buffer get added
+    private double bufferAdd;
 
     @Action
     public void onFlying(WPacketPlayInFlying packet) {
-        if(!packet.isMoved() || (getPlayer().getMovement().getDeltaXZ() == 0
-                && getPlayer().getMovement().getDeltaY() == 0)) {
+        if (!packet.isMoved() || (getPlayer().getMovement().getDeltaXZ() == 0
+                && getPlayer().getMovement().getDeltaY() == 0) || !getPlayer().getMovement().getTo().isOnGround())
             return;
-        }
 
-        boolean onGround = getPlayer().getMovement().getTo().isOnGround() && getPlayer().getBlockInformation().blocksBelow,
-                fromGround = getPlayer().getMovement().getFrom().isOnGround();
-        double lDeltaY = fromGround ? 0 : getPlayer().getMovement().getLDeltaY();
-        double predicted = onGround ? lDeltaY : (lDeltaY - 0.08) * mult;
+        final double delta = getPlayer().getMovement().getDeltaY();
 
-        if(fromGround && !onGround && getPlayer().getMovement().getDeltaY() > 0) {
-            predicted = MovementUtils.getJumpHeight(getPlayer());
-        }
+        //using the last y axis movement we got from the player, to estimate his next movement
+        predictedValue = getPlayer().getMovement().getLDeltaY();
 
-        if(Math.abs(predicted) < 0.005 && ProtocolVersion.getGameVersion().isOrAbove(ProtocolVersion.V1_9)) {
-            predicted = 0;
-        }
+        //if predicted < this, player motion y is set to 0 in mcp, so we'll do same.
+        final double min = getPlayer().getPlayerVersion().isBelow(ProtocolVersion.V1_9) ? 0.005 : 0.003;
 
-        if(lastPos.isPassed(60L)) {
-            double toCheck = (predicted - 0.08) * mult;
+        //we can be sure here that he jumped
+        if (getPlayer().getInfo().getClientAirTicks() == 1) {
+            //so we're handling his jump
+            predictedValue = MovementUtils.getJumpHeight(getPlayer());
+            bufferAdd = 2;
+        } else {
+            //this is how minecraft makes player falls, a fly wouldn't respect this rule
 
-            if(Math.abs(getPlayer().getMovement().getDeltaY() - toCheck)
-                    < Math.abs(getPlayer().getMovement().getDeltaY() - predicted)) {
-                predicted = toCheck;
+            //gravity
+            predictedValue -= 0.08;
+            //air drag
+            predictedValue *= 0.98F;
+
+            //sometimes, player doesn't send a position packet, its called "0.03", because under a 0.03 xyz length move
+            //player doesn't send a position packet
+            if (Math.abs(predictedValue - delta) > 1.0E-6) {
+                final double mightFixedPrediction = (predictedValue - 0.08) * 0.98F;
+                if (Math.abs(mightFixedPrediction - delta) < 1.0E-6)
+                    predictedValue = mightFixedPrediction;
             }
+
+            bufferAdd = 1;
         }
 
-        double deltaPredict = MathUtils.getDelta(getPlayer().getMovement().getDeltaY(), predicted);
+        if(Math.abs(predictedValue) < min)
+            predictedValue = 0;
 
-        if(!getPlayer().getInfo().isGeneralCancel()
+        //basically the difference from what we expect the player to move, and what he actually moved.
+        final double offset = MathUtils.getDelta(predictedValue, delta);
+
+        if (!getPlayer().getInfo().isGeneralCancel()
                 && getPlayer().getInfo().getBlockAbove().isPassed(1)
                 && !getPlayer().getInfo().isOnLadder()
                 && !getPlayer().getBlockInformation().inWeb
@@ -63,17 +77,17 @@ public class FlyA extends Check {
                 && !getPlayer().getBlockInformation().fenceBelow
                 && !getPlayer().getBlockInformation().onHalfBlock
                 && getPlayer().getInfo().getVelocity().isPassed(1)
-                && !getPlayer().getBlockInformation().onSlime && deltaPredict > 0.016) {
-            if(++buffer > 5) {
+                && !getPlayer().getBlockInformation().onSlime && offset > 1.0E-5) {
+            if ((buffer += bufferAdd) > 5) {
                 buffer = 5;
-                flag("dY=%.3f p=%.3f dx=%.3f", getPlayer().getMovement().getDeltaY(), predicted,
+                flag("dY=%.3f p=%.3f dx=%.3f", getPlayer().getMovement().getDeltaY(), predictedValue,
                         getPlayer().getMovement().getDeltaXZ());
             }
-        } else buffer-= buffer > 0 ? 0.25f : 0;
+        } else buffer -= buffer > 0 ? 0.25f : 0;
 
-        debug("dY=%.3f p=%.3f dx=%.3f b=%s velocity=%s", getPlayer().getMovement().getDeltaY(), predicted,
+        debug("dY=%.3f p=%.3f dx=%.3f b=%s velocity=%s", getPlayer().getMovement().getDeltaY(), predictedValue,
                 getPlayer().getMovement().getDeltaXZ(), buffer, getPlayer().getInfo().getVelocity().getPassed());
 
-        lastPos.reset();
+
     }
 }

src/main/java/dev/brighten/ac/data/handlers/GeneralInformation.java

@@ -33,4 +33,5 @@ public class GeneralInformation {
     private KLocation lastKnownGoodPosition;
     private List<Vector> velocityHistory = Collections.synchronizedList(new EvictingList<>(5));
     private List<PlayerCapabilities> possibleCapabilities = new ArrayList<>();
+    private int clientGroundTicks, clientAirTicks;
 }

src/main/java/dev/brighten/ac/data/handlers/MovementHandler.java

@@ -522,5 +522,8 @@ it
         deltaXZ = Math.hypot(deltaX, deltaZ); // Calculating here to cache since hypot() can be heavy.
         deltaYaw = to.getLoc().yaw - from.getLoc().yaw;
         deltaPitch = to.getLoc().pitch - from.getLoc().pitch;
+
+        player.getInfo().setClientGroundTicks(packet.isOnGround() ? player.getInfo().getClientGroundTicks() + 1 : 0);
+        player.getInfo().setClientAirTicks(!packet.isOnGround() ? player.getInfo().getClientAirTicks() + 1 : 0);
     }
 }

src/main/java/dev/brighten/ac/utils/MovementUtils.java

@@ -17,7 +17,7 @@ public class MovementUtils {
 
     private static Enchantment DEPTH;
 
-    public static float getJumpHeight(APlayer data) {
+    public static double getJumpHeight(APlayer data) {
         float baseHeight = 0.42f;
 
         baseHeight+= data.getPotionHandler().getEffectByType(PotionEffectType.JUMP).map(ef -> ef.getAmplifier() + 1)