Minor optimisations

Author: makuhlmann

projects/common/src/main/java/dan200/computercraft/shared/peripheral/modem/wireless/WirelessModemPeripheral.java

@@ -82,7 +82,7 @@ public double getCachedSignalDegradation(Vec3i receiverPos) {
     public void addCachedSignalDegradation(Vec3i receiverPos, double signalDegradation) {
         // Prevent overflow the lazy way
         if (cachedSignalStrengths.size() > 2000) {
-            cachedSignalStrengths = new HashMap<>();
+            cachedSignalStrengths.clear();
         }
 
         var senderPos = WirelessHelpers.floorToVec3i(getPosition());

projects/common/src/main/java/dan200/computercraft/shared/peripheral/modem/wireless/WirelessNetwork.java

@@ -12,14 +12,15 @@
 import dan200.computercraft.shared.util.WirelessHelpers;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Vec3i;
-import net.minecraft.util.Tuple;
 
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 
 public class WirelessNetwork implements PacketNetwork {
     private final Set<PacketReceiver> receivers = Collections.newSetFromMap(new ConcurrentHashMap<>());
 
+    private final static List<Vec3i> obstructionBlocks = new ArrayList<Vec3i>(2048);
+
     @Override
     public void addReceiver(PacketReceiver receiver) {
         Objects.requireNonNull(receiver, "device cannot be null");
@@ -64,13 +65,13 @@ private static void tryTransmit(PacketReceiver receiver, Packet packet, double r
                 }
             } catch (LuaException ignored) {}
 
-            boolean noCache = false;
+            boolean useCache = true;
 
             // 65534 -> Default GPS, exclude from low range for now
             if (packet.channel() > 1024 && packet.channel() != 65534) {
                 // High frequency local wireless
                 receiveRange /= 8;
-                noCache = true;
+                useCache = false;
             }
 
             if (distanceSq <= receiveRange * receiveRange) {
@@ -85,7 +86,7 @@ private static void tryTransmit(PacketReceiver receiver, Packet packet, double r
                 }
 
                 //TODO: Signal range & Different degradation based on channel - 3 groups? (low, mid, high)
-                if (!noCache) {
+                if (useCache) {
                     var cachedSignalDegradation = ((WirelessModemPeripheral)sender).getCachedSignalDegradation(receiverBlockPosition);
                     if (cachedSignalDegradation != Integer.MAX_VALUE) {
                         //System.out.println("Cache hit for " + sender.getSenderID() + " -> " + receiverBlockPosition.toString() + "!");
@@ -98,7 +99,7 @@ private static void tryTransmit(PacketReceiver receiver, Packet packet, double r
                 }
 
 
-                List<Vec3i> obstructionBlocks = WirelessHelpers.Bresenham3D(senderBlockPosition, receiverBlockPosition);
+                WirelessHelpers.Bresenham3D(obstructionBlocks, senderBlockPosition, receiverBlockPosition);
                 var signalDegradation = 0.0;
                 var diagonalCompensation = WirelessHelpers.getDiagonalCompensation(senderBlockPosition, receiverBlockPosition);
 

projects/common/src/main/java/dan200/computercraft/shared/util/WirelessHelpers.java

@@ -39,7 +39,8 @@ public static double getDiagonalCompensation(Vec3i sender, Vec3i receiver) {
         return yawDiagonal * pitchDiagonal;
     }
 
-    public static List<Vec3i> Bresenham3D(Vec3i source, Vec3i target) {
+    public static void Bresenham3D(List<Vec3i> ListOfPoints, Vec3i source, Vec3i target) {
+        ListOfPoints.clear();
         int x1 = source.getX();
         int y1 = source.getY();
         int z1 = source.getZ();
@@ -48,7 +49,6 @@ public static List<Vec3i> Bresenham3D(Vec3i source, Vec3i target) {
         int y2 = target.getY();
         int z2 = target.getZ();
 
-        List<Vec3i> ListOfPoints = new ArrayList<>();
         ListOfPoints.add(new Vec3i(x1, y1, z1));
         int dx = Math.abs(x2 - x1);
         int dy = Math.abs(y2 - y1);
@@ -129,6 +129,5 @@ public static List<Vec3i> Bresenham3D(Vec3i source, Vec3i target) {
                 ListOfPoints.add(new Vec3i(x1, y1, z1));
             }
         }
-        return ListOfPoints;
     }
 }