[core] separate Backend from View for headless rendering

4 files changed, 115 insertions, 80 deletions

diff --git a/include/mbgl/platform/default/glfw_view.hpp b/include/mbgl/platform/default/glfw_view.hpp
index 8662a90bf3..a115d03d7f 100644
--- a/include/mbgl/platform/default/glfw_view.hpp
+++ b/include/mbgl/platform/default/glfw_view.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <mbgl/mbgl.hpp>
+#include <mbgl/map/backend.hpp>
 #include <mbgl/util/run_loop.hpp>
 #include <mbgl/util/timer.hpp>
 #include <mbgl/util/geometry.hpp>
@@ -11,20 +12,36 @@
 #define GL_GLEXT_PROTOTYPES
 #include <GLFW/glfw3.h>
 
-class GLFWView : public mbgl::View {
+class GLFWView : public mbgl::View, public mbgl::Backend {
 public:
     GLFWView(bool fullscreen = false, bool benchmark = false);
     ~GLFWView() override;
 
-    float getPixelRatio() const override;
+    float getPixelRatio() const;
+
+    // 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);
+
+    void setShouldClose();
+
+    void setWindowTitle(const std::string&);
+
+    void run();
+
+private:
+    // mbgl::View implementation
+    void initialize(mbgl::Map*) override;
+    void bind() override;
     std::array<uint16_t, 2> getSize() const override;
     std::array<uint16_t, 2> getFramebufferSize() const override;
 
-    void initialize(mbgl::Map*) override;
+    // mbgl::Backend implementation
     void activate() override;
     void deactivate() override;
     void invalidate() override;
 
+    // Window callbacks
     static void onKey(GLFWwindow *window, int key, int scancode, int action, int mods);
     static void onScroll(GLFWwindow *window, double xoffset, double yoffset);
     static void onWindowResize(GLFWwindow *window, int width, int height);
@@ -32,21 +49,12 @@ public:
     static void onMouseClick(GLFWwindow *window, int button, int action, int modifiers);
     static void onMouseMove(GLFWwindow *window, double x, double y);
 
-    // 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);
-
-    void setShouldClose();
-
-    void setWindowTitle(const std::string&);
-
-    void run();
+    // Internal
     void report(float duration);
     
     void setMapChangeCallback(std::function<void(mbgl::MapChange)> callback);
     void notifyMapChange(mbgl::MapChange change) override;
 
-private:
     mbgl::Color makeRandomColor() const;
     mbgl::Point<double> makeRandomPoint() const;
     static std::shared_ptr<const mbgl::SpriteImage>
diff --git a/include/mbgl/platform/default/headless_backend.hpp b/include/mbgl/platform/default/headless_backend.hpp
new file mode 100644
index 0000000000..2f4886a365
--- /dev/null
+++ b/include/mbgl/platform/default/headless_backend.hpp
@@ -0,0 +1,78 @@
+#pragma once
+
+#include <mbgl/gl/implementation.hpp>
+
+#if MBGL_USE_QT
+class QGLWidget;
+#elif MBGL_USE_CGL
+#include <OpenGL/OpenGL.h>
+#elif MBGL_USE_GLX
+typedef struct _XDisplay Display;
+typedef struct __GLXcontextRec* GLXContext;
+typedef struct __GLXFBConfigRec* GLXFBConfig;
+typedef long unsigned int XID;
+typedef XID GLXPbuffer;
+#endif
+
+#include <mbgl/map/backend.hpp>
+#include <mbgl/gl/extension.hpp>
+
+#include <memory>
+#include <functional>
+
+namespace mbgl {
+
+class HeadlessDisplay;
+
+class HeadlessBackend : public Backend {
+public:
+    HeadlessBackend();
+    HeadlessBackend(std::shared_ptr<HeadlessDisplay>);
+    ~HeadlessBackend() override;
+
+    void invalidate() override;
+    void activate() override;
+    void deactivate() override;
+    void notifyMapChange(MapChange) override;
+
+    void setMapChangeCallback(std::function<void(MapChange)>&& cb) { mapChangeCallback = std::move(cb); }
+
+private:
+    void activateContext();
+    void deactivateContext();
+
+private:
+    // Implementation specific functions
+    static gl::glProc initializeExtension(const char*);
+    void createContext();
+    void destroyContext();
+
+    std::shared_ptr<HeadlessDisplay> display;
+
+    bool extensionsLoaded = false;
+    bool active = false;
+
+#if MBGL_USE_QT
+    QGLWidget* glContext = nullptr;
+#endif
+
+#if MBGL_USE_CGL
+    CGLContextObj glContext = nullptr;
+#endif
+
+#if MBGL_USE_EAGL
+    void *glContext = nullptr;
+#endif
+
+#if MBGL_USE_GLX
+    Display *xDisplay = nullptr;
+    GLXFBConfig *fbConfigs = nullptr;
+    GLXContext glContext = nullptr;
+    GLXPbuffer glxPbuffer = 0;
+#endif
+
+    std::function<void(MapChange)> mapChangeCallback;
+
+};
+
+} // namespace mbgl
diff --git a/include/mbgl/platform/default/headless_display.hpp b/include/mbgl/platform/default/headless_display.hpp
index edcc905221..f43e61340f 100644
--- a/include/mbgl/platform/default/headless_display.hpp
+++ b/include/mbgl/platform/default/headless_display.hpp
@@ -1,6 +1,13 @@
 #pragma once
 
-#include <mbgl/platform/default/headless_view.hpp>
+#include <mbgl/gl/implementation.hpp>
+
+#if MBGL_USE_CGL
+#include <OpenGL/OpenGL.h>
+#elif MBGL_USE_GLX
+typedef struct _XDisplay Display;
+typedef struct __GLXFBConfigRec* GLXFBConfig;
+#endif
 
 namespace mbgl {
 
diff --git a/include/mbgl/platform/default/headless_view.hpp b/include/mbgl/platform/default/headless_view.hpp
index 23f1e8251a..27af4fc9d9 100644
--- a/include/mbgl/platform/default/headless_view.hpp
+++ b/include/mbgl/platform/default/headless_view.hpp
@@ -1,95 +1,37 @@
 #pragma once
 
-#if defined(__QT__)
-#define MBGL_USE_QT 1
-class QGLWidget;
-#elif defined(__APPLE__)
-#include <TargetConditionals.h>
-#if TARGET_OS_IOS
-#define MBGL_USE_EAGL 1
-#else
-#define MBGL_USE_CGL 1
-#endif
-#else
-#define GL_GLEXT_PROTOTYPES
-#define MBGL_USE_GLX 1
-typedef struct _XDisplay Display;
-typedef struct __GLXcontextRec* GLXContext;
-typedef struct __GLXFBConfigRec* GLXFBConfig;
-typedef long unsigned int XID;
-typedef XID GLXPbuffer;
-#endif
-
-#include <mbgl/mbgl.hpp>
-#include <mbgl/gl/gl.hpp>
+#include <mbgl/map/view.hpp>
 #include <mbgl/gl/types.hpp>
-#include <mbgl/gl/extension.hpp>
-
-#include <memory>
-#include <thread>
 
 namespace mbgl {
 
-class HeadlessDisplay;
-
 class HeadlessView : public View {
 public:
-    HeadlessView(float pixelRatio, uint16_t width = 256, uint16_t height = 256);
-    HeadlessView(std::shared_ptr<HeadlessDisplay> display, float pixelRatio, uint16_t width = 256, uint16_t height = 256);
+    HeadlessView(float pixelRatio = 1, uint16_t width = 256, uint16_t height = 256);
     ~HeadlessView() override;
 
-    float getPixelRatio() const override;
+    void bind() override;
+
     std::array<uint16_t, 2> getSize() const override;
     std::array<uint16_t, 2> getFramebufferSize() const override;
 
-    void invalidate() override;
-    void activate() override;
-    void deactivate() override;
-    void notifyMapChange(MapChange) override;
 
     PremultipliedImage readStillImage(std::array<uint16_t, 2> size = {{ 0, 0 }}) override;
 
+    float getPixelRatio() const;
+
     void resize(uint16_t width, uint16_t height);
-    void setMapChangeCallback(std::function<void(MapChange)>&& cb) { mapChangeCallback = std::move(cb); }
 
 private:
-    // Implementation specific functions
-    static gl::glProc initializeExtension(const char*);
-    void createContext();
-    void destroyContext();
     void clearBuffers();
     void resizeFramebuffer();
-    void activateContext();
-    void deactivateContext();
+    void bindFramebuffer();
 
-    std::shared_ptr<HeadlessDisplay> display;
+private:
     const float pixelRatio;
     std::array<uint16_t, 2> dimensions;
 
     bool needsResize = false;
-    bool extensionsLoaded = false;
-    bool active = false;
-
-#if MBGL_USE_QT
-    QGLWidget* glContext = nullptr;
-#endif
-
-#if MBGL_USE_CGL
-    CGLContextObj glContext = nullptr;
-#endif
-
-#if MBGL_USE_EAGL
-    void *glContext = nullptr;
-#endif
-
-#if MBGL_USE_GLX
-    Display *xDisplay = nullptr;
-    GLXFBConfig *fbConfigs = nullptr;
-    GLXContext glContext = nullptr;
-    GLXPbuffer glxPbuffer = 0;
-#endif
-
-    std::function<void(MapChange)> mapChangeCallback;
 
     gl::FramebufferID fbo = 0;
     gl::RenderbufferID fboDepthStencil = 0;