Add failsafe for low RAM issue.

src/main/java/com/seibel/lod/core/builders/lodBuilding/LodBuilder.java

@@ -205,6 +205,11 @@ public class LodBuilder
 		region.isWriting++;
 		try {
 			if (region.getMinDetailLevel()!= 0) {
+				if (!LodUtil.checkRamUsage(0.05, 16)) {
+					ClientApi.LOGGER.warn("LodBuilder: Not enough RAM avalible for building lods! Skipping...");
+					return false;
+				}
+				
 				LodRegion newRegion = lodDim.getRegionFromFile(region, (byte)0, region.getVerticalQuality());
 				if (region!=newRegion)
 					throw new RuntimeException();

src/main/java/com/seibel/lod/core/builders/worldGeneration/BatchGenerator.java

@@ -83,6 +83,8 @@ public class BatchGenerator {
 		generationGroup.updateAllFutures();
 		if (!MC.hasSinglePlayerServer())
 			return;
+		if (!LodUtil.checkRamUsage(0.1, 64)) return;
+		
 		int eventsCount = generationGroup.getEventCount();
 		// If we still all jobs running, return.
 		if (eventsCount >= estimatedPointsToQueue) {

src/main/java/com/seibel/lod/core/objects/lod/LodDimension.java

@@ -26,6 +26,8 @@ import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 
+import javax.crypto.spec.GCMParameterSpec;
+
 import com.seibel.lod.core.api.ClientApi;
 import com.seibel.lod.core.enums.config.DistanceGenerationMode;
 import com.seibel.lod.core.enums.config.DropoffQuality;
@@ -316,12 +318,21 @@ public class LodDimension
 		};
 		cutAndExpandThread.execute(thread);
 	}
-	
+
+	private boolean expandOrLoadPaused = false;
 	/** Either expands or loads all regions in the rendered LOD area */
 	public void expandOrLoadRegionsAsync(int playerPosX, int playerPosZ) {
 
 		if (isExpanding) return;
+		// We have less than 10% or 1MB ram left. Don't expend.
+		if (expandOrLoadPaused && !LodUtil.checkRamUsage(0.4, 512)) {
+			//ClientApi.LOGGER.info("Not enough ram for expandOrLoadThread. Skipping...");
+			return;
+		} else if (expandOrLoadPaused) {
+			ClientApi.LOGGER.info("Enough ram for expandOrLoadThread. Restarting...");
+		}
 		isExpanding = true;
+		expandOrLoadPaused = false;
 		
 		VerticalQuality verticalQuality = CONFIG.client().graphics().quality().getVerticalQuality();
 		DropoffQuality dropoffQuality = CONFIG.client().graphics().quality().getDropoffQuality();
@@ -333,9 +344,19 @@ public class LodDimension
 		// for the same location
 		Runnable thread = () -> {
 			//ClientApi.LOGGER.info("LodDim expend Region: " + playerPosX + "," + playerPosZ);
-
 			Pos minPos = regions.getMinInRange();
 			iterateWithSpiral((int x, int z) -> {
+				if (expandOrLoadPaused) return;
+				if (!LodUtil.checkRamUsage(0.1, 32)) {
+					Runtime.getRuntime().gc();
+					if (!LodUtil.checkRamUsage(0.2, 64)) {
+						ClientApi.LOGGER.warn("Not enough ram for expandOrLoadThread. Pausing until Ram is freed...");
+						// We have less than 10% or 1MB ram left. Don't expend.
+						expandOrLoadPaused = true;
+						saveDirtyRegionsToFile(false);
+						return;
+					}
+				}
 				int regionX;
 				int regionZ;
 				LodRegion region;
@@ -355,8 +376,8 @@ public class LodDimension
 						playerPosZ);
 				minDetail = DetailDistanceUtil.getDetailLevelFromDistance(minDistance);
 				maxDetail = DetailDistanceUtil.getDetailLevelFromDistance(maxDistance);
-				
 				boolean updated = false;
+				boolean expended = false;
 				if (region == null) {
 					region = getRegionFromFile(regionPos, minDetail, verticalQuality);
 					regions.set(regionX, regionZ, region);

src/main/java/com/seibel/lod/core/util/DetailDistanceUtil.java

@@ -56,6 +56,7 @@ public class DetailDistanceUtil
 		maxDistance = CONFIG.client().graphics().quality().getLodChunkRenderDistance() * 16 * 8;
 	}
 	
+	/*// Need UPDATE and BUG FIX
 	public static int baseDistanceFunction(int detail)
 	{
 		if (detail <= minGenDetail)
@@ -79,11 +80,11 @@ public class DetailDistanceUtil
 	public static int getDrawDistanceFromDetail(int detail)
 	{
 		return baseDistanceFunction(detail);
-	}
+	}*/
 	
 	public static byte baseInverseFunction(int distance, byte minDetail)
 	{
-		byte detail;
+		int detail;
 		distance -= minDetailDistance;
 		
 		if (distance < 0 || CONFIG.client().graphics().advancedGraphics().getAlwaysDrawAtMaxQuality())
@@ -92,12 +93,12 @@ public class DetailDistanceUtil
 		double scaledDistance = distance;
 		scaledDistance /= distanceUnit;
 		if (CONFIG.client().graphics().quality().getHorizontalQuality() == HorizontalQuality.LOWEST)
-			detail = (byte) (scaledDistance);
+			detail = (int) (scaledDistance);
 		else
 		{
 			double base = CONFIG.client().graphics().quality().getHorizontalQuality().quadraticBase;
 			double logBase = Math.log(base);
-			detail = (byte) (Math.log(scaledDistance) / logBase);
+			detail = (int) (Math.log(scaledDistance) / logBase);
 		}
 		return (byte) LodUtil.clamp(minDetail, detail+minDetail, maxDetail - 1);
 	}

src/main/java/com/seibel/lod/core/util/LodUtil.java

@@ -434,4 +434,15 @@ public class LodUtil
 		numb = Float.intBitsToFloat(i);
 		return numb * (1.5F - half * numb * numb);
 	}
+	
+	// True if the requested threshold pass, or false otherwise
+	// For details, see:
+	// https://stackoverflow.com/questions/3571203/what-are-runtime-getruntime-totalmemory-and-freememory
+	public static boolean checkRamUsage(double minFreeMemoryPercent, int minFreeMemoryMB) {
+		long freeMem = Runtime.getRuntime().freeMemory() + Runtime.getRuntime().maxMemory() - Runtime.getRuntime().totalMemory();
+		if (freeMem < minFreeMemoryMB * 1024 * 1024) return false;
+		long maxMem = Runtime.getRuntime().maxMemory();
+		if (freeMem/(double)maxMem < minFreeMemoryPercent) return false;
+		return true;
+	}
 }