[ios, macos] Expose MGLMapView OpenGL context to OpenGL style layers

Added a property to MGLOpenGLStyleLayer that contains the map view’s underlying OpenGL rendering context.

2 files changed, 16 insertions, 0 deletions

diff --git a/platform/darwin/src/MGLOpenGLStyleLayer.h b/platform/darwin/src/MGLOpenGLStyleLayer.h
index df8d2c5365..f699284c32 100644
--- a/platform/darwin/src/MGLOpenGLStyleLayer.h
+++ b/platform/darwin/src/MGLOpenGLStyleLayer.h
@@ -27,6 +27,12 @@ MGL_EXPORT
 
 @property (nonatomic, weak, readonly) MGLStyle *style;
 
+#if TARGET_OS_IPHONE
+@property (nonatomic, readonly) EAGLContext *context;
+#else
+@property (nonatomic, readonly) CGLContextObj context;
+#endif
+
 - (instancetype)initWithIdentifier:(NSString *)identifier;
 
 - (void)didMoveToMapView:(MGLMapView *)mapView;
diff --git a/platform/darwin/src/MGLOpenGLStyleLayer.mm b/platform/darwin/src/MGLOpenGLStyleLayer.mm
index 678bf15bfc..945348cb03 100644
--- a/platform/darwin/src/MGLOpenGLStyleLayer.mm
+++ b/platform/darwin/src/MGLOpenGLStyleLayer.mm
@@ -107,6 +107,16 @@ private:
     return (mbgl::style::CustomLayer *)super.rawLayer;
 }
 
+#if TARGET_OS_IPHONE
+- (EAGLContext *)context {
+    return self.style.mapView.context;
+}
+#else
+- (CGLContextObj)context {
+    return self.style.mapView.context;
+}
+#endif
+
 #pragma mark - Adding to and removing from a map view
 - (void)addToStyle:(MGLStyle *)style belowLayer:(MGLStyleLayer *)otherLayer {
     self.style = style;