[core] separate Backend from View for headless rendering

3 files changed, 48 insertions, 32 deletions

diff --git a/include/mbgl/map/backend.hpp b/include/mbgl/map/backend.hpp
new file mode 100644
index 0000000000..e4a5634b88
--- /dev/null
+++ b/include/mbgl/map/backend.hpp
@@ -0,0 +1,34 @@
+#pragma once
+
+#include <mbgl/map/change.hpp>
+
+namespace mbgl {
+
+class Map;
+
+class Backend {
+public:
+    virtual ~Backend() = default;
+
+    // Called when the backend's GL context needs to be made active or inactive. These are called,
+    // as a matched pair, in four situations:
+    //
+    //   1. When releasing GL resources during Map destruction
+    //   2. When calling a CustomLayerInitializeFunction, during Map::addLayer
+    //   3. When calling a CustomLayerDeinitializeFunction, during Map::removeLayer
+    //   4. When rendering for Map::renderStill
+    //
+    // They are *not* called for Map::render; it is assumed that the correct context is already
+    // activated prior to calling Map::render.
+    virtual void activate() = 0;
+    virtual void deactivate() = 0;
+
+    // Called when the map needs to be rendered; the backend should call Map::render() at some point
+    // in the near future. (Not called for Map::renderStill() mode.)
+    virtual void invalidate() = 0;
+
+    // Notifies a watcher of map x/y/scale/rotation changes.
+    virtual void notifyMapChange(MapChange change);
+};
+
+} // namespace mbgl
diff --git a/include/mbgl/map/map.hpp b/include/mbgl/map/map.hpp
index 2831206d54..4f6207fc6f 100644
--- a/include/mbgl/map/map.hpp
+++ b/include/mbgl/map/map.hpp
@@ -19,6 +19,7 @@
 
 namespace mbgl {
 
+class Backend;
 class View;
 class FileSource;
 class Scheduler;
@@ -33,7 +34,11 @@ class Layer;
 
 class Map : private util::noncopyable {
 public:
-    explicit Map(View&, FileSource&, Scheduler&,
+    explicit Map(Backend&,
+                 View&,
+                 float pixelRatio,
+                 FileSource&,
+                 Scheduler&,
                  MapMode mapMode = MapMode::Continuous,
                  GLContextMode contextMode = GLContextMode::Unique,
                  ConstrainMode constrainMode = ConstrainMode::HeightOnly,
diff --git a/include/mbgl/map/view.hpp b/include/mbgl/map/view.hpp
index 590eef7237..0dff4b3602 100644
--- a/include/mbgl/map/view.hpp
+++ b/include/mbgl/map/view.hpp
@@ -1,24 +1,23 @@
 #pragma once
 
-#include <mbgl/map/change.hpp>
-#include <mbgl/util/chrono.hpp>
 #include <mbgl/util/image.hpp>
 
 #include <array>
-#include <functional>
-#include <memory>
 
 namespace mbgl {
 
 class Map;
 
-class View {
+class View : private util::noncopyable {
 public:
     virtual ~View() = default;
 
-    // Called directly after initialization. Must always return the same value, i.e. it may
-    // not change over time.
-    virtual float getPixelRatio() const = 0;
+    // Called when this View is associated with a Map object.
+    virtual void initialize(Map*);
+
+    // Called when this View is used for rendering. Implementations should ensure that a renderable
+    // object is bound and glClear/glDraw* calls can be done.
+    virtual void bind() = 0;
 
     // Called when the View signaled a dimension change. Must return the logical dimension
     // of this map in pixels.
@@ -30,34 +29,12 @@ public:
     // different from that rule.
     virtual std::array<uint16_t, 2> getFramebufferSize() const = 0;
 
-    // Called when this View is associated with a Map object.
-    virtual void initialize(Map*);
-
-    // Called when the view's GL context needs to be made active or inactive. These are called,
-    // as a matched pair, in four situations:
-    //
-    //   1. When releasing GL resources during Map destruction
-    //   2. When calling a CustomLayerInitializeFunction, during Map::addLayer
-    //   3. When calling a CustomLayerDeinitializeFunction, during Map::removeLayer
-    //   4. When rendering for Map::renderStill
-    //
-    // They are *not* called for Map::render; it is assumed that the correct context is already
-    // activated prior to calling Map::render.
-    virtual void activate() = 0;
-    virtual void deactivate() = 0;
-
-    // Called when the map needs to be rendered; the view should call Map::render() at some point
-    // in the near future. (Not called for Map::renderStill() mode.)
-    virtual void invalidate() = 0;
-
     // Reads the pixel data from the current framebuffer. If your View implementation
     // doesn't support reading from the framebuffer, return a null pointer.
     virtual PremultipliedImage readStillImage(std::array<uint16_t, 2> size = {{ 0, 0 }});
 
-    // Notifies a watcher of map x/y/scale/rotation changes.
-    virtual void notifyMapChange(MapChange change);
-
 protected:
     mbgl::Map *map = nullptr;
 };
+
 } // namespace mbgl