increase precision for coordinate conversions

This fixes the earthquakes while panning at high zoom levels.

Cherry-picked from 9607171612c4a40e41eddaff5230ad571571a5b9 on the perspective-improved-gestures branch.

1 files changed, 15 insertions, 16 deletions

diff --git a/src/mbgl/map/transform_state.cpp b/src/mbgl/map/transform_state.cpp
index c672ca5dea..e37f10dc6d 100644
--- a/src/mbgl/map/transform_state.cpp
+++ b/src/mbgl/map/transform_state.cpp
@@ -157,21 +157,21 @@ float TransformState::getPitch() const {
 
 #pragma mark - Projection
 
-float TransformState::lngX(float lng) const {
+double TransformState::lngX(double lng) const {
     return (180.0f + lng) * worldSize() / 360.0f;
 }
 
-float TransformState::latY(float lat) const {
-    float y_ = 180.0f / M_PI * std::log(std::tan(M_PI / 4 + lat * M_PI / 360.0f));
+double TransformState::latY(double lat) const {
+    double y_ = 180.0f / M_PI * std::log(std::tan(M_PI / 4 + lat * M_PI / 360.0f));
     return (180.0f - y_) * worldSize() / 360.0f;
 }
 
-float TransformState::xLng(float x_, float worldSize_) const {
+double TransformState::xLng(double x_, double worldSize_) const {
     return x_ * 360.0f / worldSize_ - 180.0f;
 }
 
-float TransformState::yLat(float y_, float worldSize_) const {
-    float y2 = 180.0f - y_ * 360.0f / worldSize_;
+double TransformState::yLat(double y_, double worldSize_) const {
+    double y2 = 180.0f - y_ * 360.0f / worldSize_;
     return 360.0f / M_PI * std::atan(std::exp(y2 * M_PI / 180.0f)) - 90.0f;
 }
 
@@ -245,17 +245,16 @@ TileCoordinate TransformState::pointToCoordinate(const vec2<double> point) const
     matrix::transformMat4(coord0, point0, inverted);
     matrix::transformMat4(coord1, point1, inverted);
 
-    float w0 = coord0[3];
-    float w1 = coord1[3];
-    float x0 = coord0[0] / w0;
-    float x1 = coord1[0] / w1;
-    float y0 = coord0[1] / w0;
-    float y1 = coord1[1] / w1;
-    float z0 = coord0[2] / w0;
-    float z1 = coord1[2] / w1;
+    double w0 = coord0[3];
+    double w1 = coord1[3];
+    double x0 = coord0[0] / w0;
+    double x1 = coord1[0] / w1;
+    double y0 = coord0[1] / w0;
+    double y1 = coord1[1] / w1;
+    double z0 = coord0[2] / w0;
+    double z1 = coord1[2] / w1;
 
-
-    float t = z0 == z1 ? 0 : (targetZ - z0) / (z1 - z0);
+    double t = z0 == z1 ? 0 : (targetZ - z0) / (z1 - z0);
   
     return { util::interpolate(x0, x1, t), util::interpolate(y0, y1, t), tileZoom };
 }