1 files changed, 16 insertions, 9 deletions

diff --git a/src/mbgl/algorithm/update_renderables.hpp b/src/mbgl/algorithm/update_renderables.hpp
index 0c2266ff47..c583b6b2b6 100644
--- a/src/mbgl/algorithm/update_renderables.hpp
+++ b/src/mbgl/algorithm/update_renderables.hpp
@@ -1,8 +1,8 @@
 #pragma once
 
 #include <mbgl/tile/tile_id.hpp>
+#include <mbgl/tile/tile_necessity.hpp>
 #include <mbgl/util/range.hpp>
-#include <mbgl/storage/resource.hpp>
 
 #include <unordered_set>
 
@@ -40,15 +40,15 @@ void updateRenderables(GetTileFn getTile,
 
         // if (source has the tile and bucket is loaded) {
         if (tile->isRenderable()) {
-            retainTile(*tile, Resource::Necessity::Required);
+            retainTile(*tile, TileNecessity::Required);
             renderTile(idealRenderTileID, *tile);
         } else {
             // We are now attempting to load child and parent tiles.
-            bool parentHasTriedOptional = tile->hasTriedOptional();
+            bool parentHasTriedOptional = tile->hasTriedCache();
             bool parentIsLoaded = tile->isLoaded();
 
             // The tile isn't loaded yet, but retain it anyway because it's an ideal tile.
-            retainTile(*tile, Resource::Necessity::Required);
+            retainTile(*tile, TileNecessity::Required);
             covered = true;
             overscaledZ = dataTileZoom + 1;
             if (overscaledZ > zoomRange.max) {
@@ -56,7 +56,7 @@ void updateRenderables(GetTileFn getTile,
                 const auto childDataTileID = idealDataTileID.scaledTo(overscaledZ);
                 tile = getTile(childDataTileID);
                 if (tile && tile->isRenderable()) {
-                    retainTile(*tile, Resource::Necessity::Optional);
+                    retainTile(*tile, TileNecessity::Optional);
                     renderTile(idealRenderTileID, *tile);
                 } else {
                     covered = false;
@@ -67,7 +67,7 @@ void updateRenderables(GetTileFn getTile,
                     const OverscaledTileID childDataTileID(overscaledZ, idealRenderTileID.wrap, childTileID);
                     tile = getTile(childDataTileID);
                     if (tile && tile->isRenderable()) {
-                        retainTile(*tile, Resource::Necessity::Optional);
+                        retainTile(*tile, TileNecessity::Optional);
                         renderTile(childDataTileID.toUnwrapped(), *tile);
                     } else {
                         // At least one child tile doesn't exist, so we are going to look for
@@ -97,12 +97,19 @@ void updateRenderables(GetTileFn getTile,
                     }
 
                     if (tile) {
-                        retainTile(*tile, parentIsLoaded ? Resource::Necessity::Required
-                                                         : Resource::Necessity::Optional);
+                        if (!parentIsLoaded) {
+                            // We haven't completed loading the child, so we only do an optional
+                            // (cache) request in an attempt to quickly load data that we can show.
+                            retainTile(*tile, TileNecessity::Optional);
+                        } else {
+                            // Now that we've checked the child and know for sure that we can't load
+                            // it, we attempt to load the parent from the network.
+                            retainTile(*tile, TileNecessity::Required);
+                        }
 
                         // Save the current values, since they're the parent of the next iteration
                         // of the parent tile ascent loop.
-                        parentHasTriedOptional = tile->hasTriedOptional();
+                        parentHasTriedOptional = tile->hasTriedCache();
                         parentIsLoaded = tile->isLoaded();
 
                         if (tile->isRenderable()) {