10 files changed, 112 insertions, 43 deletions
diff --git a/platform/darwin/src/MGLForegroundStyleLayer.h b/platform/darwin/src/MGLForegroundStyleLayer.h
index bcd323fb99..7e05023ef1 100644
--- a/platform/darwin/src/MGLForegroundStyleLayer.h
+++ b/platform/darwin/src/MGLForegroundStyleLayer.h
@@ -11,10 +11,11 @@ NS_ASSUME_NONNULL_BEGIN
  `MGLForegroundStyleLayer` is an abstract superclass for style layers whose
  content is defined by an `MGLSource` object.
 
- Create instances of `MGLRasterStyleLayer` and the concrete subclasses of
- `MGLVectorStyleLayer` in order to use `MGLForegroundStyleLayer`'s methods.
- Do not create instances of `MGLForegroundStyleLayer` directly, and do not
- create your own subclasses of this class.
+ Create instances of `MGLRasterStyleLayer`, `MGLHillshadeStyleLayer`, and the
+ concrete subclasses of `MGLVectorStyleLayer` in order to use
+ `MGLForegroundStyleLayer`'s methods. Do not create instances of
+ `MGLForegroundStyleLayer` directly, and do not create your own subclasses of
+ this class.
  */
 MGL_EXPORT
 @interface MGLForegroundStyleLayer : MGLStyleLayer
diff --git a/platform/darwin/src/MGLHillshadeStyleLayer.h b/platform/darwin/src/MGLHillshadeStyleLayer.h
index 199bf214c2..b2eeb59aba 100644
--- a/platform/darwin/src/MGLHillshadeStyleLayer.h
+++ b/platform/darwin/src/MGLHillshadeStyleLayer.h
@@ -2,7 +2,7 @@
 // Edit platform/darwin/scripts/generate-style-code.js, then run `make darwin-style-code`.
 
 #import "MGLFoundation.h"
-#import "MGLVectorStyleLayer.h"
+#import "MGLForegroundStyleLayer.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -24,8 +24,20 @@ typedef NS_ENUM(NSUInteger, MGLHillshadeIlluminationAnchor) {
 };
 
 /**
- Client-side hillshading visualization based on DEM data. Currently, the
- implementation only supports Mapbox Terrain RGB tiles
+ An `MGLHillshadeStyleLayer` is a style layer that renders raster <a
+ href="https://en.wikipedia.org/wiki/Digital_elevation_model">digital elevation
+ model</a> (DEM) tiles on the map.
+ 
+ Use a hillshade style layer to configure the color parameters of raster tiles
+ loaded by an `MGLRasterDEMSource` object. For example, you could use a
+ hillshade style layer to render <a
+ href="https://www.mapbox.com/help/access-elevation-data/#mapbox-terrain-rgb">Mapbox
+ Terrain-RGB</a> data.
+ 
+ To display posterized hillshading based on vector shapes, as with the <a
+ href="https://www.mapbox.com/vector-tiles/mapbox-terrain/">Mapbox Terrain</a>
+ source, use an `MGLVectorSource` object in conjunction with several
+ `MGLFillStyleLayer` objects.
 
  You can access an existing hillshade style layer using the
  `-[MGLStyle layerWithIdentifier:]` method if you know its identifier;
@@ -36,10 +48,15 @@ typedef NS_ENUM(NSUInteger, MGLHillshadeIlluminationAnchor) {
  ### Example
 
  ```swift
+ let layer = MGLHillshadeStyleLayer(identifier: "hills", source: source)
+ layer.hillshadeExaggeration = NSExpression(forConstantValue: 0.6)
+ if let canalShadowLayer = mapView.style?.layer(withIdentifier: "waterway-river-canal-shadow") {
+     mapView.style?.insertLayer(layer, below: canalShadowLayer)
+ }
  ```
  */
 MGL_EXPORT
-@interface MGLHillshadeStyleLayer : MGLVectorStyleLayer
+@interface MGLHillshadeStyleLayer : MGLForegroundStyleLayer
 
 /**
  Returns a hillshade style layer initialized with an identifier and source.
diff --git a/platform/darwin/src/MGLHillshadeStyleLayer.mm b/platform/darwin/src/MGLHillshadeStyleLayer.mm
index 538a99daf6..2383c1ce26 100644
--- a/platform/darwin/src/MGLHillshadeStyleLayer.mm
+++ b/platform/darwin/src/MGLHillshadeStyleLayer.mm
@@ -46,35 +46,6 @@ namespace mbgl {
     return @(self.rawLayer->getSourceID().c_str());
 }
 
-- (NSString *)sourceLayerIdentifier
-{
-    MGLAssertStyleLayerIsValid();
-
-    auto layerID = self.rawLayer->getSourceLayer();
-    return layerID.empty() ? nil : @(layerID.c_str());
-}
-
-- (void)setSourceLayerIdentifier:(NSString *)sourceLayerIdentifier
-{
-    MGLAssertStyleLayerIsValid();
-
-    self.rawLayer->setSourceLayer(sourceLayerIdentifier.UTF8String ?: "");
-}
-
-- (void)setPredicate:(NSPredicate *)predicate
-{
-    MGLAssertStyleLayerIsValid();
-
-    self.rawLayer->setFilter(predicate ? predicate.mgl_filter : mbgl::style::NullFilter());
-}
-
-- (NSPredicate *)predicate
-{
-    MGLAssertStyleLayerIsValid();
-
-    return [NSPredicate mgl_predicateWithFilter:self.rawLayer->getFilter()];
-}
-
 #pragma mark - Accessing the Paint Attributes
 
 - (void)setHillshadeAccentColor:(NSExpression *)hillshadeAccentColor {
diff --git a/platform/darwin/src/MGLRasterDEMSource.h b/platform/darwin/src/MGLRasterDEMSource.h
new file mode 100644
index 0000000000..d00912ca79
--- /dev/null
+++ b/platform/darwin/src/MGLRasterDEMSource.h
@@ -0,0 +1,37 @@
+#import "MGLFoundation.h"
+
+#import "MGLRasterSource.h"
+
+/**
+ `MGLRasterDEMSource` is a map content source that supplies rasterized
+ <a href="https://en.wikipedia.org/wiki/Digital_elevation_model">digital elevation model</a>
+ (DEM) tiles to be shown on the map. The location of and metadata about the
+ tiles are defined either by an option dictionary or by an external file that
+ conforms to the
+ <a href="https://github.com/mapbox/tilejson-spec/">TileJSON specification</a>.
+ A raster DEM source is added to an `MGLStyle` object along with one or more
+ `MGLHillshadeStyleLayer` objects. Use a hillshade style layer to control the
+ appearance of content supplied by the raster DEM source.
+
+ Each
+ <a href="https://www.mapbox.com/mapbox-gl-style-spec/#sources-raster-dem"><code>raster-dem</code></a>
+ source defined by the style JSON file is represented at runtime by an
+ `MGLRasterDEMSource` object that you can use to initialize new style layers.
+ You can also add and remove sources dynamically using methods such as
+ `-[MGLStyle addSource:]` and `-[MGLStyle sourceWithIdentifier:]`.
+ 
+ Currently, raster DEM sources only support the format used by
+ <a href="https://www.mapbox.com/help/access-elevation-data/#mapbox-terrain-rgb">Mapbox Terrain-RGB</a>.
+
+ ### Example
+
+ ```swift
+ let terrainRGBURL = URL(string: "mapbox://mapbox.terrain-rgb")!
+ let source = MGLRasterDEMSource(identifier: "hills", configurationURL: terrainRGBURL)
+ mapView.style?.addSource(source)
+ ```
+ */
+MGL_EXPORT
+@interface MGLRasterDEMSource : MGLRasterSource
+
+@end
diff --git a/platform/darwin/src/MGLRasterDEMSource.mm b/platform/darwin/src/MGLRasterDEMSource.mm
new file mode 100644
index 0000000000..d8639b70e3
--- /dev/null
+++ b/platform/darwin/src/MGLRasterDEMSource.mm
@@ -0,0 +1,17 @@
+#import "MGLRasterDEMSource.h"
+
+#import "MGLRasterSource_Private.h"
+#import "NSURL+MGLAdditions.h"
+
+#import <mbgl/style/sources/raster_dem_source.hpp>
+
+@implementation MGLRasterDEMSource
+
+- (std::unique_ptr<mbgl::style::RasterSource>)pendingSourceWithIdentifier:(NSString *)identifier configurationURL:(NSURL *)configurationURL tileSize:(CGFloat)tileSize {
+    NSString *configurationURLString = configurationURL.mgl_URLByStandardizingScheme.absoluteString;
+    return std::make_unique<mbgl::style::RasterDEMSource>(identifier.UTF8String,
+                                                          configurationURLString.UTF8String,
+                                                          uint16_t(round(tileSize)));
+}
+
+@end
diff --git a/platform/darwin/src/MGLRasterSource.mm b/platform/darwin/src/MGLRasterSource.mm
index 8fc18ba69d..c47cc199eb 100644
--- a/platform/darwin/src/MGLRasterSource.mm
+++ b/platform/darwin/src/MGLRasterSource.mm
@@ -33,12 +33,17 @@ static const CGFloat MGLRasterSourceRetinaTileSize = 512;
 }
 
 - (instancetype)initWithIdentifier:(NSString *)identifier configurationURL:(NSURL *)configurationURL tileSize:(CGFloat)tileSize {
-    auto source = std::make_unique<mbgl::style::RasterSource>(identifier.UTF8String,
-                                                              configurationURL.mgl_URLByStandardizingScheme.absoluteString.UTF8String,
-                                                              uint16_t(round(tileSize)));
+    auto source = [self pendingSourceWithIdentifier:identifier configurationURL:configurationURL tileSize:tileSize];
     return self = [super initWithPendingSource:std::move(source)];
 }
 
+- (std::unique_ptr<mbgl::style::RasterSource>)pendingSourceWithIdentifier:(NSString *)identifier configurationURL:(NSURL *)configurationURL tileSize:(CGFloat)tileSize {
+    NSString *configurationURLString = configurationURL.mgl_URLByStandardizingScheme.absoluteString;
+    return std::make_unique<mbgl::style::RasterSource>(identifier.UTF8String,
+                                                       configurationURLString.UTF8String,
+                                                       uint16_t(round(tileSize)));
+}
+
 - (instancetype)initWithIdentifier:(NSString *)identifier tileURLTemplates:(NS_ARRAY_OF(NSString *) *)tileURLTemplates options:(nullable NS_DICTIONARY_OF(MGLTileSourceOption, id) *)options {
     mbgl::Tileset tileSet = MGLTileSetFromTileURLTemplates(tileURLTemplates, options);
 
diff --git a/platform/darwin/src/MGLRasterSource_Private.h b/platform/darwin/src/MGLRasterSource_Private.h
index 76790bd053..6f40fbc5a9 100644
--- a/platform/darwin/src/MGLRasterSource_Private.h
+++ b/platform/darwin/src/MGLRasterSource_Private.h
@@ -1,8 +1,21 @@
 #import "MGLRasterSource.h"
 
+#include <memory>
+
+namespace mbgl {
+    namespace style {
+        class RasterSource;
+    }
+}
+
 NS_ASSUME_NONNULL_BEGIN
 
 @interface MGLRasterSource (Private)
+
+@property (nonatomic, readonly) mbgl::style::RasterSource *rawSource;
+
+- (std::unique_ptr<mbgl::style::RasterSource>)pendingSourceWithIdentifier:(NSString *)identifier configurationURL:(NSURL *)configurationURL tileSize:(CGFloat)tileSize;
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/platform/darwin/src/MGLStyle.mm b/platform/darwin/src/MGLStyle.mm
index fefd8fcf37..5128944312 100644
--- a/platform/darwin/src/MGLStyle.mm
+++ b/platform/darwin/src/MGLStyle.mm
@@ -8,6 +8,7 @@
 #import "MGLLineStyleLayer.h"
 #import "MGLCircleStyleLayer.h"
 #import "MGLSymbolStyleLayer.h"
+#import "MGLHillshadeStyleLayer.h"
 #import "MGLRasterStyleLayer.h"
 #import "MGLBackgroundStyleLayer.h"
 #import "MGLOpenGLStyleLayer.h"
@@ -19,6 +20,7 @@
 #import "MGLVectorSource.h"
 #import "MGLVectorSource_Private.h"
 #import "MGLRasterSource.h"
+#import "MGLRasterDEMSource.h"
 #import "MGLShapeSource.h"
 #import "MGLImageSource.h"
 
@@ -34,12 +36,14 @@
 #include <mbgl/style/layers/line_layer.hpp>
 #include <mbgl/style/layers/symbol_layer.hpp>
 #include <mbgl/style/layers/raster_layer.hpp>
+#include <mbgl/style/layers/hillshade_layer.hpp>
 #include <mbgl/style/layers/circle_layer.hpp>
 #include <mbgl/style/layers/background_layer.hpp>
 #include <mbgl/style/layers/custom_layer.hpp>
 #include <mbgl/style/sources/geojson_source.hpp>
 #include <mbgl/style/sources/vector_source.hpp>
 #include <mbgl/style/sources/raster_source.hpp>
+#include <mbgl/style/sources/raster_dem_source.hpp>
 #include <mbgl/style/sources/image_source.hpp>
 
 #import "NSDate+MGLAdditions.h"
@@ -231,6 +235,8 @@ static NSURL *MGLStyleURL_trafficNight;
         return [[MGLShapeSource alloc] initWithRawSource:geoJSONSource mapView:self.mapView];
     } else if (auto rasterSource = rawSource->as<mbgl::style::RasterSource>()) {
         return [[MGLRasterSource alloc] initWithRawSource:rasterSource mapView:self.mapView];
+    } else if (auto rasterDEMSource = rawSource->as<mbgl::style::RasterDEMSource>()) {
+        return [[MGLRasterDEMSource alloc] initWithRawSource:rasterDEMSource mapView:self.mapView];
     } else if (auto imageSource = rawSource->as<mbgl::style::ImageSource>()) {
         return [[MGLImageSource alloc] initWithRawSource:imageSource mapView:self.mapView];
     } else {
@@ -395,6 +401,8 @@ static NSURL *MGLStyleURL_trafficNight;
         return [[MGLSymbolStyleLayer alloc] initWithRawLayer:symbolLayer];
     } else if (auto rasterLayer = rawLayer->as<mbgl::style::RasterLayer>()) {
         return [[MGLRasterStyleLayer alloc] initWithRawLayer:rasterLayer];
+    } else if (auto hillshadeLayer = rawLayer->as<mbgl::style::HillshadeLayer>()) {
+        return [[MGLHillshadeStyleLayer alloc] initWithRawLayer:hillshadeLayer];
     } else if (auto circleLayer = rawLayer->as<mbgl::style::CircleLayer>()) {
         return [[MGLCircleStyleLayer alloc] initWithRawLayer:circleLayer];
     } else if (auto backgroundLayer = rawLayer->as<mbgl::style::BackgroundLayer>()) {
diff --git a/platform/darwin/src/MGLStyleLayer.h.ejs b/platform/darwin/src/MGLStyleLayer.h.ejs
index db16df3de5..05f450a4f8 100644
--- a/platform/darwin/src/MGLStyleLayer.h.ejs
+++ b/platform/darwin/src/MGLStyleLayer.h.ejs
@@ -11,7 +11,7 @@
 #import "MGLFoundation.h"
 #import "MGL<%-
 (type === 'background' ? '' :
- (type === 'raster' ? 'Foreground' :
+ (type === 'raster' || type === 'hillshade' ? 'Foreground' :
   'Vector'))
 %>StyleLayer.h"
 
@@ -78,7 +78,7 @@ typedef NS_ENUM(NSUInteger, MGL<%- camelize(property.name) %>) {
 MGL_EXPORT
 @interface MGL<%- camelize(type) %>StyleLayer : MGL<%-
 (type === 'background' ? '' :
- (type === 'raster' ? 'Foreground' :
+ (type === 'raster' || type === 'hillshade' ? 'Foreground' :
   'Vector'))
 %>StyleLayer
 <% if (type === 'background') { -%>
diff --git a/platform/darwin/src/MGLStyleLayer.mm.ejs b/platform/darwin/src/MGLStyleLayer.mm.ejs
index 8101c1f463..41b029791f 100644
--- a/platform/darwin/src/MGLStyleLayer.mm.ejs
+++ b/platform/darwin/src/MGLStyleLayer.mm.ejs
@@ -83,7 +83,7 @@ namespace mbgl {
     return @(self.rawLayer->getSourceID().c_str());
 }
 
-<% if (type !== 'raster') { -%>
+<% if (type !== 'raster' && type !== 'hillshade') { -%>
 - (NSString *)sourceLayerIdentifier
 {
     MGLAssertStyleLayerIsValid();