Add rule to make the World Border update with ticks instead of real time (#1550)

src/main/java/carpet/patches/TickSyncedBorderExtent.java

@@ -0,0 +1,168 @@
+package carpet.patches;
+
+import carpet.CarpetServer;
+import carpet.helpers.TickSpeed;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.util.Mth;
+import net.minecraft.world.level.border.BorderChangeListener;
+import net.minecraft.world.level.border.BorderStatus;
+import net.minecraft.world.level.border.WorldBorder;
+import net.minecraft.world.phys.shapes.BooleanOp;
+import net.minecraft.world.phys.shapes.Shapes;
+import net.minecraft.world.phys.shapes.VoxelShape;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Arrays;
+
+/**
+ * This class is essentially a copy of {@link net.minecraft.world.level.border.WorldBorder.MovingBorderExtent}
+ * but instead of using real time to lerp the border
+ * this class uses the in game ticks.
+ */
+@SuppressWarnings("JavadocReference")
+public class TickSyncedBorderExtent implements WorldBorder.BorderExtent
+{
+    private final WorldBorder border;
+    private final long realDuration;
+    private final double tickDuration;
+    private final double from;
+    private final double to;
+
+    private int ticks;
+
+    public TickSyncedBorderExtent(WorldBorder border, long realDuration, double from, double to)
+    {
+        this.border = border;
+        this.realDuration = realDuration;
+        this.tickDuration = realDuration / 50.0;
+        this.from = from;
+        this.to = to;
+        this.ticks = 0;
+    }
+
+    @Override
+    public double getMinX()
+    {
+        int maxSize = this.border.getAbsoluteMaxSize();
+        return Mth.clamp(this.border.getCenterX() - this.getSize() / 2.0, -maxSize, maxSize);
+    }
+
+    @Override
+    public double getMaxX()
+    {
+        int maxSize = this.border.getAbsoluteMaxSize();
+        return Mth.clamp(this.border.getCenterX() + this.getSize() / 2.0, -maxSize, maxSize);
+    }
+
+    @Override
+    public double getMinZ()
+    {
+        int maxSize = this.border.getAbsoluteMaxSize();
+        return Mth.clamp(this.border.getCenterZ() - this.getSize() / 2.0, -maxSize, maxSize);
+    }
+
+    @Override
+    public double getMaxZ()
+    {
+        int maxSize = this.border.getAbsoluteMaxSize();
+        return Mth.clamp(this.border.getCenterZ() + this.getSize() / 2.0, -maxSize, maxSize);
+    }
+
+    @Override
+    public double getSize()
+    {
+        double progress = this.ticks / this.tickDuration;
+        return progress < 1.0 ? Mth.lerp(progress, this.from, this.to) : this.to;
+    }
+
+    @Override
+    public double getLerpSpeed()
+    {
+        return Math.abs(this.from - this.to) / this.realDuration;
+    }
+
+    @Override
+    public long getLerpRemainingTime()
+    {
+        // Rough estimation
+        MinecraftServer server = CarpetServer.minecraft_server;
+        double ms;
+        if (server == null)
+        {
+            ms = TickSpeed.mspt;
+        }
+        else
+        {
+             ms = Arrays.stream(server.tickTimes).average().orElseThrow(IllegalStateException::new) * 1.0E-6D;
+        }
+        double tps = 1_000.0D / Math.max((TickSpeed.time_warp_start_time != 0) ? 0.0 : TickSpeed.mspt, ms);
+        return (long) ((this.tickDuration - this.ticks) / tps * 1_000);
+    }
+
+    @Override
+    public double getLerpTarget()
+    {
+        return this.to;
+    }
+
+    @NotNull
+    @Override
+    public BorderStatus getStatus()
+    {
+        return this.to < this.from ? BorderStatus.SHRINKING : BorderStatus.GROWING;
+    }
+
+    @Override
+    public void onAbsoluteMaxSizeChange()
+    {
+
+    }
+
+    @Override
+    public void onCenterChange()
+    {
+
+    }
+
+    @NotNull
+    @Override
+    public WorldBorder.BorderExtent update()
+    {
+        if (this.ticks++ % 20 == 0)
+        {
+            // We need to update any listeners
+            // Most importantly those that send updates to the client
+            // This is because the client logic uses real time
+            // So if the tick speed has changed we need to tell the client
+            for (BorderChangeListener listener : this.border.getListeners())
+            {
+                // We do not want to update DelegateBorderChangeListener
+                // This updates borders in other dimensions
+                if (!(listener instanceof BorderChangeListener.DelegateBorderChangeListener))
+                {
+                    listener.onBorderSizeLerping(this.border, this.from, this.to, this.realDuration);
+                }
+            }
+        }
+
+        return this.ticks >= this.tickDuration ? this.border.new StaticBorderExtent(this.to) : this;
+    }
+
+    @NotNull
+    @Override
+    public VoxelShape getCollisionShape()
+    {
+        return Shapes.join(
+            Shapes.INFINITY,
+            Shapes.box(
+                Math.floor(this.getMinX()),
+                Double.NEGATIVE_INFINITY,
+                Math.floor(this.getMinZ()),
+                Math.ceil(this.getMaxX()),
+                Double.POSITIVE_INFINITY,
+                Math.ceil(this.getMaxZ())
+            ),
+            BooleanOp.ONLY_FIRST
+        );
+    }
+}