add ability to set custom sprites on the Map object

include/mbgl/map/map.hpp

@@ -21,6 +21,7 @@ class View;
 class MapData;
 class MapContext;
 class StillImage;
+class SpriteImage;
 class Transform;
 class PointAnnotation;
 class ShapeAnnotation;
@@ -141,6 +142,10 @@ public:
     AnnotationIDs getAnnotationsInBounds(const LatLngBounds&, const AnnotationType& = AnnotationType::Any);
     LatLngBounds getBoundsForAnnotations(const AnnotationIDs&);
 
+    // Sprites
+    void setSprite(const std::string&, std::shared_ptr<const SpriteImage>);
+    void removeSprite(const std::string&);
+
     // Memory
     void setSourceTileCacheSize(size_t);
     void onLowMemory();

src/mbgl/geometry/sprite_atlas.cpp

@@ -170,6 +170,34 @@ void SpriteAtlas::upload() {
     }
 }
 
+void SpriteAtlas::updateDirty() {
+    auto dirtySprites = store.getDirty();
+    if (dirtySprites.empty()) {
+        return;
+    }
+
+    std::lock_guard<std::recursive_mutex> lock(mtx);
+
+    auto imageIterator = images.begin();
+    auto spriteIterator = dirtySprites.begin();
+    while (imageIterator != images.end() && spriteIterator != dirtySprites.end()) {
+        if (imageIterator->first.first < spriteIterator->first) {
+            ++imageIterator;
+        } else if (spriteIterator->first < imageIterator->first.first) {
+            ++spriteIterator;
+        } else {
+            // The two names match;
+            Holder& holder = imageIterator->second;
+            holder.texture = spriteIterator->second;
+            copy(holder, imageIterator->first.second);
+
+            ++imageIterator;
+            // Don't advance the spriteIterator because there might be another sprite with the same
+            // name, but a different wrap value.
+        }
+    }
+}
+
 void SpriteAtlas::bind(bool linear) {
     if (!texture) {
         MBGL_CHECK_ERROR(glGenTextures(1, &texture));

src/mbgl/geometry/sprite_atlas.hpp

@@ -54,6 +54,9 @@ public:
     // Binds the atlas texture to the GPU, and uploads data if it is out of date.
     void bind(bool linear = false);
 
+    // Updates sprites in the atlas texture that may have changed in the source SpriteStore object.
+    void updateDirty();
+
     // Uploads the texture to the GPU to be available when we need it. This is a lazy operation;
     // the texture is only bound when the data is out of date (=dirty).
     void upload();

src/mbgl/map/map.cpp

@@ -346,6 +346,17 @@ LatLngBounds Map::getBoundsForAnnotations(const std::vector<uint32_t>& annotatio
 }
 
 
+#pragma mark - Sprites
+
+void Map::setSprite(const std::string& name, std::shared_ptr<const SpriteImage> sprite) {
+    context->invoke(&MapContext::setSprite, name, sprite);
+}
+
+void Map::removeSprite(const std::string& name) {
+    setSprite(name, nullptr);
+}
+
+
 #pragma mark - Toggles
 
 void Map::setDebug(bool value) {

src/mbgl/map/map_context.cpp

@@ -13,6 +13,8 @@
 #include <mbgl/storage/resource.hpp>
 #include <mbgl/storage/response.hpp>
 
+#include <mbgl/geometry/sprite_atlas.hpp>
+
 #include <mbgl/style/style.hpp>
 #include <mbgl/style/style_bucket.hpp>
 #include <mbgl/style/style_layer.hpp>
@@ -373,6 +375,14 @@ void MapContext::onLowMemory() {
     view.invalidate();
 }
 
+void MapContext::setSprite(const std::string& name, std::shared_ptr<const SpriteImage> sprite) {
+    if (!style) return;
+
+    style->spriteStore->setSprite(name, sprite);
+
+    style->spriteAtlas->updateDirty();
+}
+
 void MapContext::onTileDataChanged() {
     assert(util::ThreadContext::currentlyOn(util::ThreadType::Map));
     asyncUpdate->send();

src/mbgl/map/map_context.hpp

@@ -23,6 +23,7 @@ class Painter;
 class Sprite;
 class Worker;
 class StillImage;
+class SpriteImage;
 struct LatLng;
 struct LatLngBounds;
 
@@ -64,6 +65,8 @@ public:
 
     void cleanup();
 
+    void setSprite(const std::string&, std::shared_ptr<const SpriteImage>);
+
     // Style::Observer implementation.
     void onTileDataChanged() override;
     void onResourceLoadingFailed(std::exception_ptr error) override;