[core] refactor RendererBackend

5 files changed, 122 insertions, 96 deletions

diff --git a/include/mbgl/gfx/backend_scope.hpp b/include/mbgl/gfx/backend_scope.hpp
index b92334ae0f..ae42123e97 100644
--- a/include/mbgl/gfx/backend_scope.hpp
+++ b/include/mbgl/gfx/backend_scope.hpp
@@ -1,11 +1,10 @@
 #pragma once
 
 namespace mbgl {
+namespace gfx {
 
 class RendererBackend;
 
-namespace gfx {
-
 class BackendScope {
 public:
     // There are two types of scopes: Creating an "Implicit" scope tells Mapbox GL that the
diff --git a/include/mbgl/gfx/renderer_backend.hpp b/include/mbgl/gfx/renderer_backend.hpp
new file mode 100644
index 0000000000..032c7021da
--- /dev/null
+++ b/include/mbgl/gfx/renderer_backend.hpp
@@ -0,0 +1,57 @@
+#pragma once
+
+#include <mbgl/util/util.hpp>
+
+#include <memory>
+#include <mutex>
+
+namespace mbgl {
+namespace gfx {
+
+class Context;
+class Renderable;
+class BackendScope;
+
+// TODO: Rename to "Device"
+class RendererBackend {
+protected:
+    explicit RendererBackend();
+
+public:
+    virtual ~RendererBackend();
+    RendererBackend(const RendererBackend&) = delete;
+    RendererBackend& operator=(const RendererBackend&) = delete;
+
+    // Returns the device's context.
+    Context& getContext();
+
+    // Returns a reference to the default surface that should be rendered on.
+    virtual Renderable& getDefaultRenderable() = 0;
+
+protected:
+    virtual std::unique_ptr<Context> createContext() = 0;
+
+    // Called when the backend's GL context needs to be made active or inactive. These are called,
+    // as a matched pair, exclusively through BackendScope, in two situations:
+    //
+    //   1. When releasing GL resources during Renderer destruction
+    //      (Including calling CustomLayerHost::deinitialize during RenderCustomLayer destruction)
+    //   2. When renderering through Renderer::render()
+    //      (Including calling CustomLayerHost::initialize for newly added custom layers and
+    //       CustomLayerHost::deinitialize on layer removal)
+    virtual void activate() = 0;
+    virtual void deactivate() = 0;
+
+protected:
+    std::unique_ptr<Context> context;
+    std::once_flag initialized;
+
+    friend class BackendScope;
+};
+
+MBGL_CONSTEXPR bool operator==(const RendererBackend& a, const RendererBackend& b) {
+    return &a == &b;
+}
+
+} // namespace gfx
+} // namespace mbgl
diff --git a/include/mbgl/gl/renderer_backend.hpp b/include/mbgl/gl/renderer_backend.hpp
new file mode 100644
index 0000000000..7ef8759477
--- /dev/null
+++ b/include/mbgl/gl/renderer_backend.hpp
@@ -0,0 +1,59 @@
+#pragma once
+
+#include <mbgl/gfx/renderer_backend.hpp>
+#include <mbgl/util/image.hpp>
+#include <mbgl/util/size.hpp>
+#include <mbgl/util/util.hpp>
+
+namespace mbgl {
+namespace gl {
+
+class Context;
+using ProcAddress = void (*)();
+using FramebufferID = uint32_t;
+
+class RendererBackend : public gfx::RendererBackend {
+public:
+    RendererBackend();
+    ~RendererBackend() override;
+
+    // Returns the backend's context which manages OpenGL state.
+    Context& getGLContext();
+
+    // Called prior to rendering to update the internally assumed OpenGL state.
+    virtual void updateAssumedState() = 0;
+
+protected:
+    std::unique_ptr<gfx::Context> createContext() override;
+
+    // Called with the name of an OpenGL extension that should be loaded. RendererBackend implementations
+    // must call the API-specific version that obtains the function pointer for this function,
+    // or a null pointer if unsupported/unavailable.
+    virtual ProcAddress getExtensionFunctionPointer(const char*) = 0;
+
+    // Reads the color pixel data from the currently bound framebuffer.
+    PremultipliedImage readFramebuffer(const Size&);
+
+    // A constant to signal that a framebuffer is bound, but with an unknown ID.
+    static constexpr const FramebufferID ImplicitFramebufferBinding =
+        std::numeric_limits<FramebufferID>::max();
+
+    // Tells the renderer that OpenGL state has already been set by the windowing toolkit.
+    // It sets the internal assumed state to the supplied values.
+    void assumeFramebufferBinding(FramebufferID fbo);
+    void assumeViewport(int32_t x, int32_t y, const Size&);
+    void assumeScissorTest(bool);
+
+    // Returns true when assumed framebuffer binding hasn't changed from the implicit binding.
+    bool implicitFramebufferBound();
+
+public:
+    // Triggers an OpenGL state update if the internal assumed state doesn't match the
+    // supplied values.
+    void setFramebufferBinding(FramebufferID fbo);
+    void setViewport(int32_t x, int32_t y, const Size&);
+    void setScissorTest(bool);
+};
+
+} // namespace gl
+} // namespace mbgl
diff --git a/include/mbgl/renderer/renderer.hpp b/include/mbgl/renderer/renderer.hpp
index 0bed4cdaa8..aa06210804 100644
--- a/include/mbgl/renderer/renderer.hpp
+++ b/include/mbgl/renderer/renderer.hpp
@@ -13,16 +13,19 @@
 
 namespace mbgl {
 
-class RendererBackend;
 class RendererObserver;
 class RenderedQueryOptions;
 class Scheduler;
 class SourceQueryOptions;
 class UpdateParameters;
 
+namespace gfx {
+class RendererBackend;
+} // namespace gfx
+
 class Renderer {
 public:
-    Renderer(RendererBackend&, float pixelRatio_, Scheduler&,
+    Renderer(gfx::RendererBackend&, float pixelRatio_, Scheduler&,
              GLContextMode = GLContextMode::Unique,
              const optional<std::string> programCacheDir = {},
              const optional<std::string> localFontFamily = {});
diff --git a/include/mbgl/renderer/renderer_backend.hpp b/include/mbgl/renderer/renderer_backend.hpp
deleted file mode 100644
index f75d00ebb3..0000000000
--- a/include/mbgl/renderer/renderer_backend.hpp
+++ /dev/null
@@ -1,92 +0,0 @@
-#pragma once
-
-#include <mbgl/gfx/backend_scope.hpp>
-#include <mbgl/util/image.hpp>
-#include <mbgl/util/size.hpp>
-#include <mbgl/util/util.hpp>
-
-#include <memory>
-#include <mutex>
-
-namespace mbgl {
-
-namespace gl {
-class Context;
-using ProcAddress = void (*)();
-using FramebufferID = uint32_t;
-} // namespace gl
-
-// The RendererBackend is used by the Renderer to facilitate
-// the actual rendering.
-class RendererBackend {
-public:
-    RendererBackend();
-    virtual ~RendererBackend();
-
-    // Returns the backend's context which manages OpenGL state.
-    gl::Context& getContext();
-
-    // Called prior to rendering to update the internally assumed OpenGL state.
-    virtual void updateAssumedState() = 0;
-
-    // Called when this backend is used for rendering. Implementations should ensure that a renderable
-    // 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;
-
-    virtual Size getFramebufferSize() const = 0;
-
-protected:
-    // Called with the name of an OpenGL extension that should be loaded. RendererBackend implementations
-    // must call the API-specific version that obtains the function pointer for this function,
-    // or a null pointer if unsupported/unavailable.
-    virtual gl::ProcAddress getExtensionFunctionPointer(const char*) = 0;
-
-    // Called when the backend's GL context needs to be made active or inactive. These are called,
-    // as a matched pair, exclusively through BackendScope, in two situations:
-    //
-    //   1. When releasing GL resources during Renderer destruction
-    //      (Including calling CustomLayerHost::deinitialize during RenderCustomLayer destruction)
-    //   2. When renderering through Renderer::render()
-    //      (Including calling CustomLayerHost::initialize for newly added custom layers and
-    //       CustomLayerHost::deinitialize on layer removal)
-    virtual void activate() = 0;
-    virtual void deactivate() = 0;
-
-    // Reads the color pixel data from the currently bound framebuffer.
-    PremultipliedImage readFramebuffer(const Size&) const;
-
-    // A constant to signal that a framebuffer is bound, but with an unknown ID.
-    static constexpr const gl::FramebufferID ImplicitFramebufferBinding =
-        std::numeric_limits<gl::FramebufferID>::max();
-
-    // Tells the renderer that OpenGL state has already been set by the windowing toolkit.
-    // It sets the internal assumed state to the supplied values.
-    void assumeFramebufferBinding(gl::FramebufferID fbo);
-    void assumeViewport(int32_t x, int32_t y, const Size&);
-    void assumeScissorTest(bool);
-
-    // Returns true when assumed framebuffer binding hasn't changed from the implicit binding.
-    bool implicitFramebufferBound();
-
-    // Triggers an OpenGL state update if the internal assumed state doesn't match the
-    // supplied values.
-    void setFramebufferBinding(gl::FramebufferID fbo);
-    void setViewport(int32_t x, int32_t y, const Size&);
-    void setScissorTest(bool);
-
-protected:
-    std::unique_ptr<gl::Context> context;
-
-private:
-    std::once_flag initialized;
-
-    friend class gfx::BackendScope;
-};
-
-MBGL_CONSTEXPR bool operator==(const RendererBackend& a, const RendererBackend& b) {
-    return &a == &b;
-}
-
-} // namespace mbgl