Fix Z-fighting at very high heights

core/src/main/java/com/seibel/distanthorizons/core/render/renderer/LodRenderProgram.java

@@ -191,7 +191,13 @@ public class LodRenderProgram extends ShaderProgram implements IDhApiShaderProgr
 		//  this is to try and allow the fragment culling to go farther than the near clip plane.
 		//  Currently this only works for certain FOV/screen ratio combos.
 		dhNearClipDistance *= 2.0f;
-		setUniform(clipDistanceUniform, dhNearClipDistance);
+		// if the player is very high up and the near clip plane has been modified, disable the distance clipping
+		// we're high enough that nothing will render on top of the player and this can cause issues otherwise
+		if (RenderUtil.getHeightBasedNearClipOverride() != -1)
+		{
+			dhNearClipDistance = 1.0f;
+		}
+		this.setUniform(this.clipDistanceUniform, dhNearClipDistance);
 	}
 	
 	@Override

core/src/main/java/com/seibel/distanthorizons/core/util/RenderUtil.java

@@ -28,6 +28,7 @@ import com.seibel.distanthorizons.core.pos.DhChunkPos;
 import com.seibel.distanthorizons.core.world.IDhClientWorld;
 import com.seibel.distanthorizons.core.wrapperInterfaces.minecraft.IMinecraftClientWrapper;
 import com.seibel.distanthorizons.core.wrapperInterfaces.minecraft.IMinecraftRenderWrapper;
+import com.seibel.distanthorizons.core.wrapperInterfaces.world.IClientLevelWrapper;
 import com.seibel.distanthorizons.coreapi.util.MathUtil;
 import com.seibel.distanthorizons.coreapi.util.math.Mat4f;
 import com.seibel.distanthorizons.coreapi.util.math.Vec3f;
@@ -148,11 +149,6 @@ public class RenderUtil
 		// in James' testing a near clip plane distance of 2 blocks is enough to allow the fragment
 		// culling to take effect instead of seeing the near clip plane.
 		float nearClipDist = RenderUtil.getNearClipPlaneDistanceInBlocks(partialTicks);
-		if (Config.Client.Advanced.Debugging.lodOnlyMode.get())
-		{
-			nearClipDist = 0.1f;
-		}
-		
 		float farClipDist = (float) RenderUtil.getFarClipPlaneDistanceInBlocks();
 		
 		// Create a copy of the current matrix, so it won't be modified.
@@ -210,6 +206,15 @@ public class RenderUtil
 			}
 		}
 		
+		
+		// TODO move into method and use to override discard value in shader program
+		float heightOverride = getHeightBasedNearClipOverride();
+		if (heightOverride != -1.0f)
+		{
+			nearClipPlane = heightOverride;
+		}
+		
+		
 		// modify based on the player's FOV
 		double fov = MC_RENDER.getFov(partialTicks);
 		double aspectRatio = (double) MC_RENDER.getScreenWidth() / MC_RENDER.getScreenHeight();
@@ -227,6 +232,28 @@ public class RenderUtil
 		return (int)((lodBlockDist + LodUtil.REGION_WIDTH) * Math.sqrt(2));
 	}
 	
+	/** @return -1 if no override is necessary */
+	public static float getHeightBasedNearClipOverride()
+	{
+		// TODO always using the client level like this might cause issues with immersive portals and the like,
+		//  but for now it should work well enough
+		IClientLevelWrapper level = MC.getWrappedClientLevel();
+		// a level should always be loaded, but just in case
+		if (level != null)
+		{
+			// if the player is a significant distance above the work, increase the
+			// near clip plane to fix Z imprecision issues
+			int playerHeight = MC.getPlayerBlockPos().y;
+			int levelMaxHeight = level.getHeight();
+			if (playerHeight > levelMaxHeight + 1_000)
+			{
+				return playerHeight - (levelMaxHeight + 1000);
+			}
+		}
+		
+		return -1.0f;
+	}
+	
 	/** @return false if LODs shouldn't be rendered for any reason */
 	public static boolean shouldLodsRender(ILevelWrapper levelWrapper)
 	{