[core] Move TransformState::{un,}project() to Projection

include/mbgl/util/projection.hpp

@@ -46,6 +46,22 @@ public:
 
         return LatLng(latitude, longitude);
     }
+
+    static Point<double> project(const LatLng& latLng, double scale) {
+        return Point<double> {
+            util::LONGITUDE_MAX + latLng.longitude,
+            util::LONGITUDE_MAX - util::RAD2DEG * std::log(std::tan(M_PI / 4 + latLng.latitude * M_PI / util::DEGREES_MAX))
+        } * worldSize(scale) / util::DEGREES_MAX;
+    }
+
+    static LatLng unproject(const Point<double>& p, double scale, LatLng::WrapMode wrapMode = LatLng::Unwrapped) {
+        auto p2 = p * util::DEGREES_MAX / worldSize(scale);
+        return LatLng {
+            util::DEGREES_MAX / M_PI * std::atan(std::exp((util::LONGITUDE_MAX - p2.y) * util::DEG2RAD)) - 90.0,
+            p2.x - util::LONGITUDE_MAX,
+            wrapMode
+        };
+    }
 };
 
 } // namespace mbgl

src/mbgl/map/transform.cpp

@@ -113,8 +113,8 @@ void Transform::easeTo(const CameraOptions& camera, const AnimationOptions& anim
     // Find the shortest path otherwise.
     else startLatLng.unwrapForShortestPath(latLng);
 
-    const Point<double> startPoint = state.project(startLatLng);
-    const Point<double> endPoint = state.project(latLng);
+    const Point<double> startPoint = Projection::project(startLatLng, state.scale);
+    const Point<double> endPoint = Projection::project(latLng, state.scale);
 
     ScreenCoordinate center = getScreenCoordinate(padding);
     center.y = state.height - center.y;
@@ -133,7 +133,6 @@ void Transform::easeTo(const CameraOptions& camera, const AnimationOptions& anim
     Duration duration = animation.duration ? *animation.duration : Duration::zero();
 
     const double startScale = state.scale;
-    const double startWorldSize = Projection::worldSize(startScale);
     const double startAngle = state.angle;
     const double startPitch = state.pitch;
     state.panning = latLng != startLatLng;
@@ -142,7 +141,7 @@ void Transform::easeTo(const CameraOptions& camera, const AnimationOptions& anim
 
     startTransition(camera, animation, [=](double t) {
         Point<double> framePoint = util::interpolate(startPoint, endPoint, t);
-        LatLng frameLatLng = state.unproject(framePoint, startWorldSize);
+        LatLng frameLatLng = Projection::unproject(framePoint, startScale);
         double frameScale = util::interpolate(startScale, scale, t);
         state.setLatLngZoom(frameLatLng, state.scaleZoom(frameScale));
 
@@ -184,8 +183,8 @@ void Transform::flyTo(const CameraOptions &camera, const AnimationOptions &anima
     LatLng startLatLng = getLatLng(padding).wrapped();
     startLatLng.unwrapForShortestPath(latLng);
 
-    const Point<double> startPoint = state.project(startLatLng);
-    const Point<double> endPoint = state.project(latLng);
+    const Point<double> startPoint = Projection::project(startLatLng, state.scale);
+    const Point<double> endPoint = Projection::project(latLng, state.scale);
 
     ScreenCoordinate center = getScreenCoordinate(padding);
     center.y = state.height - center.y;
@@ -289,7 +288,7 @@ void Transform::flyTo(const CameraOptions &camera, const AnimationOptions &anima
         return;
     }
 
-    const double startWorldSize = Projection::worldSize(state.scale);
+    const double startScale = state.scale;
     state.panning = true;
     state.scaling = true;
     state.rotating = angle != startAngle;
@@ -305,7 +304,7 @@ void Transform::flyTo(const CameraOptions &camera, const AnimationOptions &anima
         double frameZoom = startZoom + state.scaleZoom(1 / w(s));
 
         // Convert to geographic coordinates and set the new viewpoint.
-        LatLng frameLatLng = state.unproject(framePoint, startWorldSize);
+        LatLng frameLatLng = Projection::unproject(framePoint, startScale);
         state.setLatLngZoom(frameLatLng, frameZoom);
 
         if (angle != startAngle) {

src/mbgl/map/transform_state.cpp

@@ -201,22 +201,6 @@ bool TransformState::isGestureInProgress() const {
 
 #pragma mark - Projection
 
-Point<double> TransformState::project(const LatLng& ll) const {
-    return Point<double>(
-        (util::LONGITUDE_MAX + ll.longitude),
-        (util::LONGITUDE_MAX - util::RAD2DEG * std::log(std::tan(M_PI / 4 + ll.latitude * M_PI / util::DEGREES_MAX)))
-    ) * Projection::worldSize(scale) / util::DEGREES_MAX;
-}
-
-LatLng TransformState::unproject(const Point<double>& p, double worldSize, LatLng::WrapMode wrapMode) const {
-    Point<double> p2 = p * util::DEGREES_MAX / worldSize;
-    return LatLng(
-        util::DEGREES_MAX / M_PI * std::atan(std::exp((util::LONGITUDE_MAX - p2.y) * util::DEG2RAD)) - 90.0f,
-        p2.x - util::LONGITUDE_MAX,
-        wrapMode
-    );
-}
-
 double TransformState::zoomScale(double zoom) const {
     return std::pow(2.0f, zoom);
 }
@@ -232,7 +216,7 @@ ScreenCoordinate TransformState::latLngToScreenCoordinate(const LatLng& latLng)
 
     mat4 mat = coordinatePointMatrix(getZoom());
     vec4 p;
-    Point<double> pt = project(latLng) / double(util::tileSize);
+    Point<double> pt = Projection::project(latLng, scale) / double(util::tileSize);
     vec4 c = {{ pt.x, pt.y, 0, 1 }};
     matrix::transformMat4(p, c, mat);
     return { p[0] / p[3], height - p[1] / p[3] };
@@ -274,7 +258,7 @@ LatLng TransformState::screenCoordinateToLatLng(const ScreenCoordinate& point, L
     double z1 = coord1[2] / w1;
     double t = z0 == z1 ? 0 : (targetZ - z0) / (z1 - z0);
 
-    return unproject(util::interpolate(p0, p1, t), scale, wrapMode);
+    return Projection::unproject(util::interpolate(p0, p1, t), scale / util::tileSize, wrapMode);
 }
 
 mat4 TransformState::coordinatePointMatrix(double z) const {
@@ -321,10 +305,10 @@ void TransformState::constrain(double& scale_, double& x_, double& y_) const {
 }
 
 void TransformState::moveLatLng(const LatLng& latLng, const ScreenCoordinate& anchor) {
-    auto centerCoord = project(getLatLng(LatLng::Unwrapped));
-    auto latLngCoord = project(latLng);
-    auto anchorCoord = project(screenCoordinateToLatLng(anchor));
-    setLatLngZoom(unproject(centerCoord + latLngCoord - anchorCoord, Projection::worldSize(scale)), getZoom());
+    auto centerCoord = Projection::project(getLatLng(LatLng::Unwrapped), scale);
+    auto latLngCoord = Projection::project(latLng, scale);
+    auto anchorCoord = Projection::project(screenCoordinateToLatLng(anchor), scale);
+    setLatLngZoom(Projection::unproject(centerCoord + latLngCoord - anchorCoord, scale), getZoom());
 }
 
 void TransformState::setLatLngZoom(const LatLng &latLng, double zoom) {

src/mbgl/map/transform_state.hpp

@@ -66,13 +66,10 @@ public:
     bool isPanning() const;
     bool isGestureInProgress() const;
 
-    // Conversion and projection
+    // Conversion
     ScreenCoordinate latLngToScreenCoordinate(const LatLng&) const;
     LatLng screenCoordinateToLatLng(const ScreenCoordinate&, LatLng::WrapMode = LatLng::Unwrapped) const;
 
-    Point<double> project(const LatLng&) const;
-    LatLng unproject(const Point<double>&, double worldSize, LatLng::WrapMode = LatLng::Unwrapped) const;
-
     double zoomScale(double zoom) const;
     double scaleZoom(double scale) const;
 

src/mbgl/util/tile_coordinate.hpp

@@ -5,6 +5,7 @@
 #include <mbgl/tile/geometry_tile_data.hpp>
 #include <mbgl/tile/tile_id.hpp>
 #include <mbgl/util/geometry.hpp>
+#include <mbgl/util/projection.hpp>
 
 namespace mbgl {
 
@@ -19,7 +20,7 @@ public:
 
     static TileCoordinate fromLatLng(const TransformState& state, double zoom, const LatLng& latLng) {
         const double scale = std::pow(2, zoom - state.getZoom());
-        return { state.project(latLng) * scale / double(util::tileSize), zoom };
+        return { Projection::project(latLng, state.getScale()) * scale / double(util::tileSize), zoom };
     }
 
     static TileCoordinate fromScreenCoordinate(const TransformState& state, double zoom, const ScreenCoordinate& screenCoordinate) {