Fix #2266 by sorting regions after render list generation

common/src/main/java/net/caffeinemc/mods/sodium/client/render/chunk/RenderSection.java

@@ -69,9 +69,9 @@ public RenderSection(RenderRegion region, int chunkX, int chunkY, int chunkZ) {
         this.chunkY = chunkY;
         this.chunkZ = chunkZ;
 
-        int rX = this.getChunkX() & (RenderRegion.REGION_WIDTH - 1);
-        int rY = this.getChunkY() & (RenderRegion.REGION_HEIGHT - 1);
-        int rZ = this.getChunkZ() & (RenderRegion.REGION_LENGTH - 1);
+        int rX = this.getChunkX() & RenderRegion.REGION_WIDTH_M;
+        int rY = this.getChunkY() & RenderRegion.REGION_HEIGHT_M;
+        int rZ = this.getChunkZ() & RenderRegion.REGION_LENGTH_M;
 
         this.sectionIndex = LocalSectionIndex.pack(rX, rY, rZ);
 

common/src/main/java/net/caffeinemc/mods/sodium/client/render/chunk/RenderSectionManager.java

@@ -146,7 +146,7 @@ private void createTerrainRenderList(Camera camera, Viewport viewport, int frame
 
         this.occlusionCuller.findVisible(visitor, viewport, searchDistance, useOcclusionCulling, frame);
 
-        this.renderLists = visitor.createRenderLists();
+        this.renderLists = visitor.createRenderLists(viewport);
         this.taskLists = visitor.getRebuildLists();
     }
 

common/src/main/java/net/caffeinemc/mods/sodium/client/render/chunk/lists/SortedRenderLists.java

@@ -1,9 +1,7 @@
 package net.caffeinemc.mods.sodium.client.render.chunk.lists;
 
 import it.unimi.dsi.fastutil.objects.ObjectArrayList;
-import net.caffeinemc.mods.sodium.client.render.chunk.RenderSection;
 import net.caffeinemc.mods.sodium.client.util.iterator.ReversibleObjectArrayIterator;
-import net.caffeinemc.mods.sodium.client.render.chunk.region.RenderRegion;
 
 /**
  * Stores one render list of sections per region, sorted by the order in which
@@ -27,44 +25,4 @@ public ReversibleObjectArrayIterator<ChunkRenderList> iterator(boolean reverse)
     public static SortedRenderLists empty() {
         return EMPTY;
     }
-
-    public static class Builder {
-        private final ObjectArrayList<ChunkRenderList> lists = new ObjectArrayList<>();
-        private final int frame;
-
-        public Builder(int frame) {
-            this.frame = frame;
-        }
-
-        public void add(RenderSection section) {
-            RenderRegion region = section.getRegion();
-            ChunkRenderList list = region.getRenderList();
-
-            // Even if a section does not have render objects, we must ensure the render list is initialized and put
-            // into the sorted queue of lists, so that we maintain the correct order of draw calls.
-            if (list.getLastVisibleFrame() != this.frame) {
-                list.reset(this.frame);
-
-                this.lists.add(list);
-            }
-
-            // Only add the section to the render list if it actually contains render objects
-            if (section.getFlags() != 0) {
-                list.add(section);
-            }
-        }
-
-        public SortedRenderLists build() {
-            var filtered = new ObjectArrayList<ChunkRenderList>(this.lists.size());
-
-            // Filter any empty render lists
-            for (var list : this.lists) {
-                if (list.size() > 0) {
-                    filtered.add(list);
-                }
-            }
-
-            return new SortedRenderLists(filtered);
-        }
-    }
 }

common/src/main/java/net/caffeinemc/mods/sodium/client/render/chunk/lists/VisibleChunkCollector.java

@@ -5,6 +5,7 @@
 import net.caffeinemc.mods.sodium.client.render.chunk.RenderSection;
 import net.caffeinemc.mods.sodium.client.render.chunk.occlusion.OcclusionCuller;
 import net.caffeinemc.mods.sodium.client.render.chunk.region.RenderRegion;
+import net.caffeinemc.mods.sodium.client.render.viewport.Viewport;
 
 import java.util.*;
 
@@ -61,8 +62,31 @@ private void addToRebuildLists(RenderSection section) {
         }
     }
 
-    public SortedRenderLists createRenderLists() {
-        return new SortedRenderLists(this.sortedRenderLists);
+    public SortedRenderLists createRenderLists(Viewport viewport) {
+        // sort the regions by distance to fix rare region ordering bugs
+        var transform = viewport.getTransform();
+        var cameraX = transform.intX >> (4 + RenderRegion.REGION_WIDTH_SH);
+        var cameraY = transform.intY >> (4 + RenderRegion.REGION_HEIGHT_SH);
+        var cameraZ = transform.intZ >> (4 + RenderRegion.REGION_LENGTH_SH);
+        var size = this.sortedRenderLists.size();
+
+        var items = new int[size];
+        for (var i = 0; i < size; i++) {
+            var region = this.sortedRenderLists.get(i).getRegion();
+            var x = Math.abs(region.getRawX() - cameraX);
+            var y = Math.abs(region.getRawY() - cameraY);
+            var z = Math.abs(region.getRawZ() - cameraZ);
+            items[i] = (x + y + z) << 16 | i;
+        }
+
+        Arrays.sort(items);
+
+        var sorted = new ObjectArrayList<ChunkRenderList>(size);
+        for (var key : items) {
+            sorted.add(this.sortedRenderLists.get(key & 0xFFFF));
+        }
+
+        return new SortedRenderLists(sorted);
     }
 
     public Map<ChunkUpdateType, ArrayDeque<RenderSection>> getRebuildLists() {

common/src/main/java/net/caffeinemc/mods/sodium/client/render/chunk/region/RenderRegion.java

@@ -24,13 +24,13 @@ public class RenderRegion {
     public static final int REGION_HEIGHT = 4;
     public static final int REGION_LENGTH = 8;
 
-    private static final int REGION_WIDTH_M = RenderRegion.REGION_WIDTH - 1;
-    private static final int REGION_HEIGHT_M = RenderRegion.REGION_HEIGHT - 1;
-    private static final int REGION_LENGTH_M = RenderRegion.REGION_LENGTH - 1;
+    public static final int REGION_WIDTH_M = RenderRegion.REGION_WIDTH - 1;
+    public static final int REGION_HEIGHT_M = RenderRegion.REGION_HEIGHT - 1;
+    public static final int REGION_LENGTH_M = RenderRegion.REGION_LENGTH - 1;
 
-    protected static final int REGION_WIDTH_SH = Integer.bitCount(REGION_WIDTH_M);
-    protected static final int REGION_HEIGHT_SH = Integer.bitCount(REGION_HEIGHT_M);
-    protected static final int REGION_LENGTH_SH = Integer.bitCount(REGION_LENGTH_M);
+    public static final int REGION_WIDTH_SH = Integer.bitCount(REGION_WIDTH_M);
+    public static final int REGION_HEIGHT_SH = Integer.bitCount(REGION_HEIGHT_M);
+    public static final int REGION_LENGTH_SH = Integer.bitCount(REGION_LENGTH_M);
 
     public static final int REGION_SIZE = REGION_WIDTH * REGION_HEIGHT * REGION_LENGTH;
 
@@ -64,6 +64,18 @@ public static long key(int x, int y, int z) {
         return SectionPos.asLong(x, y, z);
     }
 
+    public int getRawX() {
+        return this.x;
+    }
+
+    public int getRawY() {
+        return this.y;
+    }
+
+    public int getRawZ() {
+        return this.z;
+    }
+
     public int getChunkX() {
         return this.x << REGION_WIDTH_SH;
     }