fix: crash during active scan with no more world

docs/roadmap.md

@@ -2,8 +2,8 @@
 
 ## Next steps
 
-- [ ] only one setting at a time is saved (bug: #20, pr: #24)
-- [ ] `NullPointerException` when a scanner is active and world disappears (bug: #21, pr: ?)
+- [x] only one setting at a time is saved (bug: #20, pr: #24)
+- [x] `NullPointerException` when a scanner is active and world disappears (bug: #21, pr: #25)
 - [ ] clumps of blocks (bug for internal walls: #22, issue: #23, pr: ?)
   - [ ] bounds for frustum
   - [ ] walls no longer flicker

fabric/any/src/main/java/com/midnightbits/scanner/fabric/FabricAnimationHost.java

@@ -24,6 +24,9 @@ public class FabricAnimationHost extends AbstractAnimatorHost {
     public void initialize(Sonar source) {
         this.source = source;
         ClientTickEvents.END_CLIENT_TICK.register((client) -> {
+            if (client.world == null)
+                return;
+
             this.tick(Clock.currentTimeMillis());
             this.source.remove(this.source.oldEchoes(new MinecraftClientCore(client)));
         });

fabric/any/src/main/java/com/midnightbits/scanner/rt/core/fabric/MinecraftClientCore.java

@@ -12,6 +12,7 @@
 import net.minecraft.block.BlockState;
 import net.minecraft.client.MinecraftClient;
 import net.minecraft.util.math.BlockPos;
+import org.jetbrains.annotations.Nullable;
 
 public class MinecraftClientCore implements ClientCore {
     private final MinecraftClient client;
@@ -21,16 +22,20 @@ public MinecraftClientCore(MinecraftClient client) {
     }
 
     @Override
-    public BlockInfo getBlockInfo(V3i pos) {
-        assert client.world != null;
+    public @Nullable BlockInfo getBlockInfo(V3i pos) {
+        if (client.world == null) {
+            return null;
+        }
         BlockState state = client.world.getBlockState(new BlockPos(Minecraft.vec3iOf(pos)));
         Block block = state == null ? null : state.getBlock();
         return new MinecraftBlockInfo(state, block);
     }
 
     @Override
-    public V3i getPlayerPos() {
-        assert client.player != null;
+    public @Nullable V3i getPlayerPos() {
+        if (client.player == null) {
+            return null;
+        }
         return Minecraft.v3iOf(client.player.getBlockPos());
     }
 

scanner/build.gradle

@@ -14,10 +14,11 @@ repositories {
 }
 
 dependencies {
+	compileOnly 'org.jetbrains:annotations:16.0.2'
 	implementation 'com.google.code.gson:gson:2.11.0'
 	implementation 'org.joml:joml:1.10.8'
-	implementation 'org.slf4j:slf4j-api:1.7.+'
-	implementation 'org.slf4j:slf4j-log4j12:1.7.29'
+	implementation 'org.slf4j:slf4j-api:2.0.+'
+	implementation 'org.slf4j:slf4j-log4j13:1.0.+'
 	implementation 'org.apache.commons:commons-text:1.12.0'
 
 	testImplementation 'org.junit.jupiter:junit-jupiter-api:5.10.3'

scanner/src/main/java/com/midnightbits/scanner/rt/core/ClientCore.java

@@ -5,11 +5,12 @@
 
 import com.midnightbits.scanner.rt.math.V3i;
 import com.midnightbits.scanner.rt.text.Text;
+import org.jetbrains.annotations.Nullable;
 
 public interface ClientCore {
-    BlockInfo getBlockInfo(V3i pos);
+    @Nullable BlockInfo getBlockInfo(V3i pos);
 
-    V3i getPlayerPos();
+    @Nullable V3i getPlayerPos();
 
     float getCameraPitch();
 

scanner/src/main/java/com/midnightbits/scanner/sonar/BlockEchoes.java

@@ -73,6 +73,9 @@ public Predicate<BlockEcho> oldEchoes(ClientCore client) {
             }
 
             final var info = client.getBlockInfo(block.position());
+            if (info == null) {
+                return true;
+            }
             return !block.id().equals(info.getId());
         });
     }

scanner/src/main/java/com/midnightbits/scanner/sonar/Sonar.java

@@ -82,6 +82,8 @@ public boolean sendPing(ClientCore client, SlicePacer pacer, ScanWaveConsumer wa
         if (reflections != null)
             return false;
         reflections = Reflections.fromPlayerPov(client, blockDistance, blockRadius);
+        if (reflections == null)
+            return false;
         pacer.registerCallback((now) -> {
             if (!reflections.hasNextSlice()) {
                 reflections = null;
@@ -137,6 +139,9 @@ public void processSlice(ScanWaveConsumer waveConsumer, Set<Id> blocks) {
 
             for (final var pos : slice.items()) {
                 final var info = client.getBlockInfo(pos);
+                if (info == null) {
+                    break;
+                }
                 if (info.isAir()) {
                     LOGGER.debug("({}) is air", pos);
                     continue;
@@ -167,8 +172,12 @@ public void processSlice(ScanWaveConsumer waveConsumer, Set<Id> blocks) {
             waveConsumer.advance(slice.items(), echoes.stream().toList());
         }
 
-        static Reflections fromPlayerPov(ClientCore client, int blockDistance, int blockRadius) {
-            return new Reflections(client, client.getPlayerPos(), blockDistance, blockRadius);
+        static @Nullable Reflections fromPlayerPov(ClientCore client, int blockDistance, int blockRadius) {
+            final var pos = client.getPlayerPos();
+            if (pos == null) {
+                return null;
+            }
+            return new Reflections(client, pos, blockDistance, blockRadius);
         }
 
         private ConeOfBlocks coneOfBlocksFromCamera(int blockDistance, int blockRadius) {