use enum for neighboring tiles

4 files changed, 96 insertions, 44 deletions

diff --git a/src/mbgl/geometry/dem_pyramid.cpp b/src/mbgl/geometry/dem_pyramid.cpp
index 7d20fcb587..2674d7a9d8 100644
--- a/src/mbgl/geometry/dem_pyramid.cpp
+++ b/src/mbgl/geometry/dem_pyramid.cpp
@@ -23,25 +23,25 @@ void DEMPyramid::loadFromImage(PremultipliedImage& image){
     // replaced when the tile's neighboring tiles are loaded and the accurate data can be backfilled using
     // DEMPyramid#backfillBorder
     
-    for (int32_t x = 0; x < first.dim; x++) {
-        // left vertical border
-        first.set(-1, x, first.get(0, x));
-        
-        // right vertical border
-        first.set(first.dim, x, first.get(first.dim - 1, x));
-        
-        //left horizontal border
-        first.set(x, -1, first.get(x, 0));
-        
-        // right horizontal border
-        first.set(x, first.dim, first.get(x, first.dim - 1));
-    }
-    
-    // corners
-    first.set(-1, -1, first.get(0, 0));
-    first.set(first.dim, -1, first.get(first.dim - 1, 0));
-    first.set( -1, first.dim, first.get(0, first.dim - 1));
-    first.set(first.dim, first.dim, first.get(first.dim - 1, first.dim - 1));
+//    for (int32_t x = 0; x < first.dim; x++) {
+//        // left vertical border
+//        first.set(-1, x, first.get(0, x));
+//
+//        // right vertical border
+//        first.set(first.dim, x, first.get(first.dim - 1, x));
+//
+//        //left horizontal border
+//        first.set(x, -1, first.get(x, 0));
+//
+//        // right horizontal border
+//        first.set(x, first.dim, first.get(x, first.dim - 1));
+//    }
+//
+//    // corners
+//    first.set(-1, -1, first.get(0, 0));
+//    first.set(first.dim, -1, first.get(first.dim - 1, 0));
+//    first.set( -1, first.dim, first.get(0, first.dim - 1));
+//    first.set(first.dim, first.dim, first.get(first.dim - 1, first.dim - 1));
     
     levels.emplace_back(std::move(first));
     loaded = true;
diff --git a/src/mbgl/renderer/sources/render_raster_dem_source.cpp b/src/mbgl/renderer/sources/render_raster_dem_source.cpp
index bd9c5a33de..4672952f4e 100644
--- a/src/mbgl/renderer/sources/render_raster_dem_source.cpp
+++ b/src/mbgl/renderer/sources/render_raster_dem_source.cpp
@@ -61,7 +61,7 @@ void RenderRasterDEMSource::update(Immutable<style::Source::Impl> baseImpl_,
                        });
 }
 
-static void fillBorder(const RasterDEMTile& tile, const RasterDEMTile& borderTile){
+static void fillBorder(RasterDEMTile& tile, const RasterDEMTile& borderTile, const DEMTileNeighbors mask ){
     int dx = borderTile.id.canonical.x - tile.id.canonical.x;
     const int8_t dy = borderTile.id.canonical.y - tile.id.canonical.y;
     const uint32_t dim = pow(2, tile.id.canonical.z);
@@ -82,51 +82,61 @@ static void fillBorder(const RasterDEMTile& tile, const RasterDEMTile& borderTil
 
     if (tileDEM->isLoaded() && borderDEM->isLoaded()){
         tileDEM->backfillBorder(*borderDEM, dx, dy);
+        // update the bitmask to indicate that this tiles have been backfilled by flipping the relevant bit
+        tile.neighboringTiles = tile.neighboringTiles | mask;
+        std::cout << "backfilled: " << int(tile.id.canonical.z)<< "/" << tile.id.canonical.x << "/" << tile.id.canonical.y << "\n";
+        std::cout << "with neighbor " << int(mask) << " : " << int(borderTile.id.canonical.z)<< "/" << borderTile.id.canonical.x << "/" << borderTile.id.canonical.y << "\n";
+        tileBucket->prepared = false;
     }
-    tileBucket->prepared = false;
-    borderBucket->prepared = false;
 }
 
 void RenderRasterDEMSource::onTileChanged(Tile& tile){
     RasterDEMTile& demtile = static_cast<RasterDEMTile&>(tile);
 
+    std::map<DEMTileNeighbors, DEMTileNeighbors> opposites = {
+        { DEMTileNeighbors::Left, DEMTileNeighbors::Right },
+        { DEMTileNeighbors::Right, DEMTileNeighbors::Left },
+        { DEMTileNeighbors::TopLeft, DEMTileNeighbors::BottomRight },
+        { DEMTileNeighbors::TopCenter, DEMTileNeighbors::BottomCenter },
+        { DEMTileNeighbors::TopRight, DEMTileNeighbors::BottomLeft },
+        { DEMTileNeighbors::BottomRight,  DEMTileNeighbors::TopLeft },
+        { DEMTileNeighbors::BottomCenter, DEMTileNeighbors:: TopCenter },
+        { DEMTileNeighbors::BottomLeft, DEMTileNeighbors::TopRight }
+    };
+
     if (tile.isRenderable() && demtile.neighboringTiles != 0b11111111) {
         const CanonicalTileID canonical = tile.id.canonical;
         const uint dim = std::pow(2, canonical.z);
-        const int px = (canonical.x - 1 + dim) % dim;
+        const uint32_t px = (canonical.x - 1 + dim) % dim;
         const int pxw = canonical.x == 0 ? tile.id.wrap - 1 : tile.id.wrap;
-        const int nx = (canonical.x + 1 + dim) % dim;
+        const uint32_t nx = (canonical.x + 1 + dim) % dim;
         const int nxw = (canonical.x + 1 == dim) ? tile.id.wrap + 1 : tile.id.wrap;
+        const int lowerY = (canonical.y + 1) == dim ? canonical.y : canonical.y + 1;
+        const int upperY = canonical.y == 0 ? canonical.y : canonical.y - 1;
 
         std::vector<OverscaledTileID> neighbors = {
+            // left and right neighbor
             OverscaledTileID(tile.id.overscaledZ, pxw, canonical.z, px, canonical.y),
-            OverscaledTileID(tile.id.overscaledZ, nxw, canonical.z, nx, canonical.y)
+            OverscaledTileID(tile.id.overscaledZ, nxw, canonical.z, nx, canonical.y),
+            // upper neighboring tiles, if they exist
+            OverscaledTileID(tile.id.overscaledZ, pxw, canonical.z, px, upperY),
+            OverscaledTileID(tile.id.overscaledZ, tile.id.wrap, canonical.z, canonical.x, upperY),
+            OverscaledTileID(tile.id.overscaledZ, nxw, canonical.z, nx, upperY),
+            // lower neighboring tiles, if they exist
+            OverscaledTileID(tile.id.overscaledZ, pxw, canonical.z, px, lowerY),
+            OverscaledTileID(tile.id.overscaledZ, tile.id.wrap, canonical.z, canonical.x, lowerY),
+            OverscaledTileID(tile.id.overscaledZ, nxw, canonical.z, nx, lowerY)
         };
-        // upper neighboring tiles, if they exist
-        if (canonical.y > 0) {
-            neighbors.push_back(OverscaledTileID(tile.id.overscaledZ, pxw, canonical.z, px, canonical.y - 1));
-            neighbors.push_back(OverscaledTileID(tile.id.overscaledZ, tile.id.wrap, canonical.z, canonical.x, canonical.y - 1));
-            neighbors.push_back(OverscaledTileID(tile.id.overscaledZ, nxw, canonical.z, nx, canonical.y - 1));
-        }
-        // lower neighboring tiles, if they exist
-        if (canonical.y + 1 < dim){
-            neighbors.push_back(OverscaledTileID(tile.id.overscaledZ, pxw, canonical.z, px, canonical.y + 1));
-            neighbors.push_back(OverscaledTileID(tile.id.overscaledZ, tile.id.wrap, canonical.z, canonical.x, canonical.y + 1));
-            neighbors.push_back(OverscaledTileID(tile.id.overscaledZ, nxw, canonical.z, nx, canonical.y + 1));
-        }
+
         for (uint8_t i = 0; i < neighbors.size(); i++) {
-            unsigned char mask = std::pow(2, i);
+            DEMTileNeighbors mask = DEMTileNeighbors(std::pow(2,i));
             if ((demtile.neighboringTiles & mask) != mask) {
                 OverscaledTileID neighborid = neighbors[i];
                 Tile* renderableNeighbor = tilePyramid.getTile(neighborid);
                 if (renderableNeighbor != nullptr && renderableNeighbor->isRenderable()) {
                     RasterDEMTile& borderTile = static_cast<RasterDEMTile&>(*renderableNeighbor);
-                    fillBorder(demtile, borderTile);
-                    fillBorder(borderTile, demtile);
-
-                    // update the bitmasks to indicate that these tiles have been backfilled by flipping the relevant bit
-                    demtile.neighboringTiles = demtile.neighboringTiles | mask;
-                    borderTile.neighboringTiles = borderTile.neighboringTiles | mask;
+                    fillBorder(demtile, borderTile, mask);
+                    fillBorder(borderTile, demtile, opposites[mask]);
                 }
             }
         }
diff --git a/src/mbgl/renderer/sources/render_raster_dem_source.hpp b/src/mbgl/renderer/sources/render_raster_dem_source.hpp
index b32d3705cb..b524a83359 100644
--- a/src/mbgl/renderer/sources/render_raster_dem_source.hpp
+++ b/src/mbgl/renderer/sources/render_raster_dem_source.hpp
@@ -6,6 +6,38 @@
 
 namespace mbgl {
 
+enum class DEMTileNeighbors {
+  // 0b00000001
+  Left = 1 << 0,
+  // 0b00000010
+  Right = 1 << 1,
+  // 0b00000100
+  TopLeft = 1 << 2,
+  // 0b00001000
+  TopCenter = 1 << 3,
+  // 0b00010000
+  TopRight = 1 << 4,
+  // 0b00100000
+  BottomLeft = 1 << 5,
+  // 0b01000000
+  BottomCenter = 1 << 6,
+  // 0b10000000
+  BottomRight = 1 << 7
+};
+
+inline unsigned char operator|(unsigned char a, DEMTileNeighbors b) {
+    return static_cast<unsigned char>(a | int(b));
+};
+
+inline unsigned char operator&(unsigned char a, DEMTileNeighbors b) {
+    return static_cast<unsigned char>(a & int(b));
+}
+
+inline bool operator!=(unsigned char a, DEMTileNeighbors b) {
+    return a != static_cast<unsigned char>(b);
+}
+
+
 class RenderRasterDEMSource : public RenderSource {
 public:
     RenderRasterDEMSource(Immutable<style::RasterDEMSource::Impl>);
diff --git a/src/mbgl/tile/raster_dem_tile.cpp b/src/mbgl/tile/raster_dem_tile.cpp
index 929768787e..e435589941 100644
--- a/src/mbgl/tile/raster_dem_tile.cpp
+++ b/src/mbgl/tile/raster_dem_tile.cpp
@@ -20,6 +20,16 @@ RasterDEMTile::RasterDEMTile(const OverscaledTileID& id_,
       mailbox(std::make_shared<Mailbox>(*Scheduler::GetCurrent())),
       worker(parameters.workerScheduler,
              ActorRef<RasterDEMTile>(*this, mailbox)) {
+
+    if ( id.canonical.y == 0 ){
+        // this tile doesn't have upper neighboring tiles so marked those as backfilled
+        neighboringTiles = neighboringTiles | 0b00011100;
+    }
+
+    if (id.canonical.y + 1 == std::pow(2, id.canonical.z)){
+        // this tile doesn't have lower neighboring tiles so marked those as backfilled
+        neighboringTiles = neighboringTiles | 0b11100000;
+    }
 }
 
 RasterDEMTile::~RasterDEMTile() = default;