[core] move gl::Context to Backend and refactor View

7 files changed, 66 insertions, 111 deletions

diff --git a/include/mbgl/map/backend.hpp b/include/mbgl/map/backend.hpp
index e4a5634b88..c11d094906 100644
--- a/include/mbgl/map/backend.hpp
+++ b/include/mbgl/map/backend.hpp
@@ -2,13 +2,21 @@
 
 #include <mbgl/map/change.hpp>
 
+#include <memory>
+
 namespace mbgl {
 
-class Map;
+namespace gl {
+class Context;
+} // namespace gl
 
 class Backend {
 public:
-    virtual ~Backend() = default;
+    Backend();
+    virtual ~Backend();
+
+    // Returns the backend's context which manages OpenGL state.
+    gl::Context& getContext();
 
     // Called when the backend's GL context needs to be made active or inactive. These are called,
     // as a matched pair, in four situations:
@@ -29,6 +37,9 @@ public:
 
     // Notifies a watcher of map x/y/scale/rotation changes.
     virtual void notifyMapChange(MapChange change);
+
+private:
+    const std::unique_ptr<gl::Context> context;
 };
 
 } // namespace mbgl
diff --git a/include/mbgl/map/map.hpp b/include/mbgl/map/map.hpp
index 4f6207fc6f..b1c840e68d 100644
--- a/include/mbgl/map/map.hpp
+++ b/include/mbgl/map/map.hpp
@@ -2,8 +2,6 @@
 
 #include <mbgl/util/optional.hpp>
 #include <mbgl/util/chrono.hpp>
-#include <mbgl/util/image.hpp>
-#include <mbgl/map/update.hpp>
 #include <mbgl/map/mode.hpp>
 #include <mbgl/util/geo.hpp>
 #include <mbgl/util/feature.hpp>
@@ -35,7 +33,7 @@ class Layer;
 class Map : private util::noncopyable {
 public:
     explicit Map(Backend&,
-                 View&,
+                 std::array<uint16_t, 2> size,
                  float pixelRatio,
                  FileSource&,
                  Scheduler&,
@@ -47,14 +45,14 @@ public:
 
     // Register a callback that will get called (on the render thread) when all resources have
     // been loaded and a complete render occurs.
-    using StillImageCallback = std::function<void (std::exception_ptr, PremultipliedImage&&)>;
-    void renderStill(StillImageCallback callback);
+    using StillImageCallback = std::function<void (std::exception_ptr)>;
+    void renderStill(View&, StillImageCallback callback);
 
-    // Main render function.
-    void render();
+    // Triggers a repaint.
+    void triggerRepaint();
 
-    // Notifies the Map that the state has changed and an update might be necessary.
-    void update(Update update);
+    // Main render function.
+    void render(View&);
 
     // Styling
     void addClass(const std::string&);
@@ -138,6 +136,7 @@ public:
     ViewportMode getViewportMode() const;
 
     // Size
+    void setSize(const std::array<uint16_t, 2>&);
     uint16_t getWidth() const;
     uint16_t getHeight() const;
 
diff --git a/include/mbgl/map/update.hpp b/include/mbgl/map/update.hpp
deleted file mode 100644
index 1da7e3ac92..0000000000
--- a/include/mbgl/map/update.hpp
+++ /dev/null
@@ -1,31 +0,0 @@
-#pragma once
-
-#include <mbgl/util/traits.hpp>
-
-namespace mbgl {
-
-enum class Update {
-    Nothing                   = 0,
-    Dimensions                = 1 << 1,
-    Classes                   = 1 << 2,
-    RecalculateStyle          = 1 << 3,
-    RenderStill               = 1 << 4,
-    Repaint                   = 1 << 5,
-    AnnotationStyle           = 1 << 6,
-    AnnotationData            = 1 << 7,
-    Layout                    = 1 << 8
-};
-
-constexpr Update operator|(Update lhs, Update rhs) {
-    return Update(mbgl::underlying_type(lhs) | mbgl::underlying_type(rhs));
-}
-
-constexpr Update& operator|=(Update& lhs, const Update& rhs) {
-    return (lhs = lhs | rhs);
-}
-
-constexpr bool operator& (Update lhs, Update rhs) {
-    return mbgl::underlying_type(lhs) & mbgl::underlying_type(rhs);
-}
-
-} // namespace mbgl
diff --git a/include/mbgl/map/view.hpp b/include/mbgl/map/view.hpp
index 0dff4b3602..6517c6b220 100644
--- a/include/mbgl/map/view.hpp
+++ b/include/mbgl/map/view.hpp
@@ -1,8 +1,6 @@
 #pragma once
 
-#include <mbgl/util/image.hpp>
-
-#include <array>
+#include <mbgl/util/noncopyable.hpp>
 
 namespace mbgl {
 
@@ -12,29 +10,11 @@ class View : private util::noncopyable {
 public:
     virtual ~View() = default;
 
-    // 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.
+    // object is bound and glClear/glDraw* calls can be done. They should also make sure that
+    // calling .bind() repeatedly is a no-op and that the appropriate gl::Context values are
+    // set to the current state.
     virtual void bind() = 0;
-
-    // Called when the View signaled a dimension change. Must return the logical dimension
-    // of this map in pixels.
-    virtual std::array<uint16_t, 2> getSize() const = 0;
-
-    // Called for every frame that is being rendered. Must return the absolute dimensions of
-    // the current framebuffer. Typically, this is the logical width scaled by the pixel ratio,
-    // but in case the view was moved to display with a different pixel ratio, it can also be
-    // different from that rule.
-    virtual std::array<uint16_t, 2> getFramebufferSize() const = 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 }});
-
-protected:
-    mbgl::Map *map = nullptr;
 };
 
 } // namespace mbgl
diff --git a/include/mbgl/platform/default/glfw_view.hpp b/include/mbgl/platform/default/glfw_view.hpp
index a115d03d7f..e832cd70d1 100644
--- a/include/mbgl/platform/default/glfw_view.hpp
+++ b/include/mbgl/platform/default/glfw_view.hpp
@@ -19,6 +19,8 @@ public:
 
     float getPixelRatio() const;
 
+    void setMap(mbgl::Map*);
+
     // Callback called when the user presses the key mapped to style change.
     // The expected action is to set a new style, different to the current one.
     void setChangeStyleCallback(std::function<void()> callback);
@@ -29,18 +31,18 @@ public:
 
     void run();
 
-private:
     // mbgl::View implementation
-    void initialize(mbgl::Map*) override;
+    void updateViewBinding();
     void bind() override;
-    std::array<uint16_t, 2> getSize() const override;
-    std::array<uint16_t, 2> getFramebufferSize() const override;
+    std::array<uint16_t, 2> getSize() const;
+    std::array<uint16_t, 2> getFramebufferSize() const;
 
     // mbgl::Backend implementation
     void activate() override;
     void deactivate() override;
     void invalidate() override;
 
+private:
     // Window callbacks
     static void onKey(GLFWwindow *window, int key, int scancode, int action, int mods);
     static void onScroll(GLFWwindow *window, double xoffset, double yoffset);
@@ -76,6 +78,8 @@ private:
     std::function<void(mbgl::MapChange)> mapChangeCallback;
 
 private:
+    mbgl::Map* map = nullptr;
+
     bool fullscreen = false;
     const bool benchmark = false;
     bool tracking = false;
diff --git a/include/mbgl/platform/default/headless_view.hpp b/include/mbgl/platform/default/headless_view.hpp
deleted file mode 100644
index 27af4fc9d9..0000000000
--- a/include/mbgl/platform/default/headless_view.hpp
+++ /dev/null
@@ -1,41 +0,0 @@
-#pragma once
-
-#include <mbgl/map/view.hpp>
-#include <mbgl/gl/types.hpp>
-
-namespace mbgl {
-
-class HeadlessView : public View {
-public:
-    HeadlessView(float pixelRatio = 1, uint16_t width = 256, uint16_t height = 256);
-    ~HeadlessView() override;
-
-    void bind() override;
-
-    std::array<uint16_t, 2> getSize() const override;
-    std::array<uint16_t, 2> getFramebufferSize() const override;
-
-
-    PremultipliedImage readStillImage(std::array<uint16_t, 2> size = {{ 0, 0 }}) override;
-
-    float getPixelRatio() const;
-
-    void resize(uint16_t width, uint16_t height);
-
-private:
-    void clearBuffers();
-    void resizeFramebuffer();
-    void bindFramebuffer();
-
-private:
-    const float pixelRatio;
-    std::array<uint16_t, 2> dimensions;
-
-    bool needsResize = false;
-
-    gl::FramebufferID fbo = 0;
-    gl::RenderbufferID fboDepthStencil = 0;
-    gl::RenderbufferID fboColor = 0;
-};
-
-} // namespace mbgl
diff --git a/include/mbgl/platform/default/offscreen_view.hpp b/include/mbgl/platform/default/offscreen_view.hpp
new file mode 100644
index 0000000000..034aa3aaf3
--- /dev/null
+++ b/include/mbgl/platform/default/offscreen_view.hpp
@@ -0,0 +1,33 @@
+#pragma once
+
+#include <mbgl/map/view.hpp>
+#include <mbgl/gl/framebuffer.hpp>
+#include <mbgl/gl/renderbuffer.hpp>
+#include <mbgl/util/optional.hpp>
+#include <mbgl/util/image.hpp>
+
+namespace mbgl {
+
+namespace gl {
+class Context;
+} // namespace gl
+
+class OffscreenView : public View {
+public:
+    OffscreenView(gl::Context&, std::array<uint16_t, 2> size = {{ 256, 256 }});
+
+    void bind() override;
+
+    PremultipliedImage readStillImage();
+
+    std::array<uint16_t, 2> getSize() const;
+
+private:
+    gl::Context& context;
+    std::array<uint16_t, 2> size;
+    optional<gl::Framebuffer> framebuffer;
+    optional<gl::Renderbuffer<gl::RenderbufferType::RGBA>> color;
+    optional<gl::Renderbuffer<gl::RenderbufferType::DepthStencil>> depthStencil;
+};
+
+} // namespace mbgl