[test] Added TileCoordinate tests

cmake/test-files.cmake

@@ -91,6 +91,7 @@ set(MBGL_TEST_FILES
     test/tile/raster_tile.test.cpp
     test/tile/tile_id.test.cpp
     test/tile/vector_tile.test.cpp
+    test/tile/tile_coordinate.test.cpp
 
     # util
     test/util/async_task.test.cpp

test/tile/tile_coordinate.test.cpp

@@ -0,0 +1,92 @@
+#include <mbgl/test/util.hpp>
+
+#include <mbgl/map/change.hpp>
+#include <mbgl/map/transform.hpp>
+#include <mbgl/map/transform_state.hpp>
+#include <mbgl/tile/tile.hpp>
+#include <mbgl/tile/tile_id.hpp>
+#include <mbgl/util/constants.hpp>
+#include <mbgl/util/geometry.hpp>
+#include <mbgl/util/tile_coordinate.hpp>
+
+
+using namespace mbgl;
+
+TEST(TileCoordinate, FromLatLng) {
+    size_t changeCount = 0;
+    std::vector<MapChange> changes = {
+        MapChangeRegionWillChange,
+        MapChangeRegionDidChange,
+    };
+    auto onMapChange = [&](MapChange change) {
+        ASSERT_EQ(change, changes[changeCount]);
+        ++changeCount;
+    };
+
+    Transform transform(onMapChange);
+
+    const double max = util::tileSize;
+    const std::array<uint16_t, 2> size { { uint16_t(max), uint16_t(max) } };
+    transform.resize(size);
+
+    // Center, top-left, bottom-left, bottom-right, top-right edges.
+    std::vector<std::pair<LatLng, ScreenCoordinate>> edges {
+        { {}, { max / 2.0, max / 2.0 } },
+        { { util::LATITUDE_MAX, -util::LONGITUDE_MAX }, { 0, max } },
+        { { -util::LATITUDE_MAX, -util::LONGITUDE_MAX }, { 0, 0 } },
+        { { -util::LATITUDE_MAX, util::LONGITUDE_MAX }, { max, 0 } },
+        { { util::LATITUDE_MAX, util::LONGITUDE_MAX }, { max, max } },
+    };
+
+    for (const auto& pair : edges) {
+        const auto& latLng = pair.first;
+        const auto& screenCoordinate = pair.second;
+        const auto base = TileCoordinate::fromLatLng(transform.getState(), 0, latLng);
+
+        // 16 is the maximum zoom level where we actually compute placements.
+        for (uint8_t integerZoom = 0; integerZoom <= 16; ++integerZoom) {
+            const double zoom = integerZoom;
+            const double maxTilesPerAxis = std::pow(2.0, zoom);
+            const Point<double> tilePoint = {
+                latLng.longitude == 0 ? 0.5 : latLng.longitude == -util::LONGITUDE_MAX ? 0 : 1.0,
+                latLng.latitude  == 0 ? 0.5 : latLng.latitude  == -util::LATITUDE_MAX  ? 1.0 : 0,
+            };
+
+            const auto fromLatLng = TileCoordinate::fromLatLng(transform.getState(), zoom, latLng);
+            ASSERT_DOUBLE_EQ(fromLatLng.z, zoom);
+            ASSERT_DOUBLE_EQ(fromLatLng.p.x, tilePoint.x * maxTilesPerAxis);
+            ASSERT_NEAR(fromLatLng.p.y, tilePoint.y * maxTilesPerAxis, 1.0e-7);
+
+            const auto fromScreenCoordinate = TileCoordinate::fromScreenCoordinate(transform.getState(), zoom, screenCoordinate);
+            ASSERT_DOUBLE_EQ(fromScreenCoordinate.z, fromLatLng.z);
+            ASSERT_NEAR(fromScreenCoordinate.p.x, fromLatLng.p.x, 0.99);
+            ASSERT_NEAR(fromScreenCoordinate.p.y, fromLatLng.p.y, 0.99);
+
+            const auto zoomed = base.zoomTo(zoom);
+            ASSERT_DOUBLE_EQ(zoomed.z, zoom);
+            ASSERT_DOUBLE_EQ(zoomed.p.x, fromLatLng.p.x);
+            ASSERT_DOUBLE_EQ(zoomed.p.y, fromLatLng.p.y);
+        }
+    }
+}
+
+TEST(TileCoordinate, ToGeometryCoordinate) {
+    std::vector<Point<double>> edges {
+        { 0.5, 0.5 }, { 0, 0 }, { 1, 0 }, { 1, 1 }, { 0, 1 }
+    };
+
+    for (uint8_t zoom = 0; zoom <= 16; ++zoom) {
+        uint32_t maxTilesPerAxis = std::pow(2, zoom);
+        for (const auto& edge : edges) {
+            uint32_t tileX = edge.x == 0 ? 0 : edge.x == 1 ? maxTilesPerAxis - 1 : (maxTilesPerAxis / 2.0) - 1;
+            uint32_t tileY = edge.y == 0 ? 0 : edge.y == 1 ? maxTilesPerAxis - 1 : (maxTilesPerAxis / 2.0) - 1;
+            UnwrappedTileID unwrapped(0, CanonicalTileID { zoom, tileX, tileY });
+
+            auto tilePointX = ((edge.x * maxTilesPerAxis) - tileX) * util::EXTENT;
+            auto tilePointY = ((edge.y * maxTilesPerAxis) - tileY) * util::EXTENT;
+            GeometryCoordinate point = TileCoordinate::toGeometryCoordinate(unwrapped, edge);
+            ASSERT_DOUBLE_EQ(point.x, tilePointX);
+            ASSERT_DOUBLE_EQ(point.y, tilePointY);
+        }
+    }
+}