Do region sorting even when the tree traversal does section ordering correctly

Author: douira

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

@@ -12,40 +12,39 @@ public interface RenderListProvider extends SortItemsProvider {
 
     default SortedRenderLists createRenderLists(Viewport viewport) {
         var sectionPos = viewport.getChunkCoord();
-        var renderLists = this.getUnsortedRenderLists();
-
-        // sort the regions by distance to fix rare region ordering bugs if necessary
-        if (!this.orderIsSorted()) {
-            var cameraX = sectionPos.getX() >> RenderRegion.REGION_WIDTH_SH;
-            var cameraY = sectionPos.getY() >> RenderRegion.REGION_HEIGHT_SH;
-            var cameraZ = sectionPos.getZ() >> RenderRegion.REGION_LENGTH_SH;
-
-            var size = renderLists.size();
-            var sortItems = this.ensureSortItemsOfLength(size);
-
-            for (var i = 0; i < size; i++) {
-                var region = renderLists.get(i).getRegion();
-                var x = Math.abs(region.getX() - cameraX);
-                var y = Math.abs(region.getY() - cameraY);
-                var z = Math.abs(region.getZ() - cameraZ);
-                sortItems[i] = (x + y + z) << 16 | i;
-            }
-
-            IntArrays.unstableSort(sortItems, 0, size);
-
-            var sorted = new ObjectArrayList<ChunkRenderList>(size);
-            for (var i = 0; i < size; i++) {
-                var key = sortItems[i];
-                var renderList = renderLists.get(key & 0xFFFF);
-                sorted.add(renderList);
-            }
-            renderLists = sorted;
+        var unsorted = this.getUnsortedRenderLists();
+
+        // sort the regions by distance to fix rare region ordering problems.
+        // regions need to be sorted even when the order is generated by a correctly traversed section tree
+        // but sections don't need to be sorted within regions
+        var cameraX = sectionPos.getX() >> RenderRegion.REGION_WIDTH_SH;
+        var cameraY = sectionPos.getY() >> RenderRegion.REGION_HEIGHT_SH;
+        var cameraZ = sectionPos.getZ() >> RenderRegion.REGION_LENGTH_SH;
+
+        var size = unsorted.size();
+        var sortItems = this.ensureSortItemsOfLength(size);
+
+        for (var i = 0; i < size; i++) {
+            var region = unsorted.get(i).getRegion();
+            var x = Math.abs(region.getX() - cameraX);
+            var y = Math.abs(region.getY() - cameraY);
+            var z = Math.abs(region.getZ() - cameraZ);
+            sortItems[i] = (x + y + z) << 16 | i;
         }
 
-        for (var list : renderLists) {
+        IntArrays.unstableSort(sortItems, 0, size);
+
+        var sorted = new ObjectArrayList<ChunkRenderList>(size);
+        for (var i = 0; i < size; i++) {
+            var key = sortItems[i];
+            var renderList = unsorted.get(key & 0xFFFF);
+            sorted.add(renderList);
+        }
+
+        for (var list : sorted) {
             list.prepareForRender(sectionPos, this);
         }
 
-        return new SortedRenderLists(renderLists);
+        return new SortedRenderLists(sorted);
     }
 }