Stop using server-side tracked position when attempting to account fo…

…r teleports not always moving entity client side; expand from client area instead (GrimAnticheat#1902)

src/main/java/ac/grim/grimac/utils/collisions/datatypes/SimpleCollisionBox.java

@@ -393,6 +393,18 @@ public double distance(SimpleCollisionBox box) {
         return hxz - (xwidth + zwidth + bxwidth + bzwidth) / 4;
     }
 
+    public double distanceX(double x) {
+        return x >= this.minX && x <= this.maxX ? 0.0 : Math.min(Math.abs(x - this.minX), Math.abs(x - this.maxX));
+    }
+
+    public double distanceY(double y) {
+        return y >= this.minY && y <= this.maxY ? 0.0 : Math.min(Math.abs(y - this.minY), Math.abs(y - this.maxY));
+    }
+
+    public double distanceZ(double z) {
+        return z >= this.minZ && z <= this.maxZ ? 0.0 : Math.min(Math.abs(z - this.minZ), Math.abs(z - this.maxZ));
+    }
+
     /**
      * Calculates intersection with the given ray between a certain distance
      * interval.

src/main/java/ac/grim/grimac/utils/data/ReachInterpolationData.java

@@ -32,6 +32,7 @@ public class ReachInterpolationData {
     private int interpolationStepsLowBound = 0;
     private int interpolationStepsHighBound = 0;
     private int interpolationSteps = 1;
+    private boolean expandNonRelative = false;
 
     public ReachInterpolationData(GrimPlayer player, SimpleCollisionBox startingLocation, TrackedPosition position, PacketEntity entity) {
         final boolean isPointNine = !player.compensatedEntities.getSelf().inVehicle() && player.getClientVersion().isNewerThanOrEquals(ClientVersion.V_1_9);
@@ -114,6 +115,9 @@ public SimpleCollisionBox getPossibleLocationCombined() {
                     startingLocation.maxZ + (step * stepMaxZ)));
         }
 
+        if (expandNonRelative)
+            minimumInterpLocation.expand(0.03125D, 0.015625D, 0.03125D);
+
         return minimumInterpLocation;
     }
 
@@ -139,4 +143,8 @@ public String toString() {
                 ", interpolationStepsHighBound=" + interpolationStepsHighBound +
                 '}';
     }
+
+    public void expandNonRelative() {
+        expandNonRelative = true;
+    }
 }

src/main/java/ac/grim/grimac/utils/data/packetentity/PacketEntity.java

@@ -134,6 +134,17 @@ public void onFirstTransaction(boolean relative, boolean hasPos, double relX, do
                 }
                 trackedServerPosition.setPos(vec3d);
             } else {
+                // I think we can reduce this but I'm too lazy to minimize interpolations needed so...
+                SimpleCollisionBox clientArea = newPacketLocation.getPossibleLocationCombined();
+                // In versions < 1.16.2 when the client receives non-relative teleport for an entity
+                // And they move less by the thresholds given, the entity does not move client side
+                if (player.getClientVersion().isOlderThanOrEquals(ClientVersion.V_1_16_1)
+                        && clientArea.distanceX(relX) < 0.03125D
+                        && clientArea.distanceY(relY) < 0.015625D
+                        && clientArea.distanceZ(relZ) < 0.03125D
+                ) {
+                    newPacketLocation.expandNonRelative();
+                }
                 trackedServerPosition.setPos(new Vector3d(relX, relY, relZ));
                 // ViaVersion desync's here for teleports
                 // It simply teleports the entity with its position divided by 32... ignoring the offset this causes.