shell/platform/windows/egl/manager.h

// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef FLUTTER_SHELL_PLATFORM_WINDOWS_EGL_MANAGER_H_
#define FLUTTER_SHELL_PLATFORM_WINDOWS_EGL_MANAGER_H_

// OpenGL ES and EGL includes
#include <EGL/egl.h>
#include <EGL/eglext.h>
#include <EGL/eglplatform.h>
#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>

// Windows platform specific includes
#include <d3d11.h>
#include <windows.h>
#include <wrl/client.h>
#include <memory>

#include "flutter/fml/macros.h"
#include "flutter/shell/platform/windows/egl/context.h"

namespace flutter {
namespace egl {

// A manager for initializing ANGLE correctly and using it to create and
// destroy surfaces
class Manager {
 public:
  static std::unique_ptr<Manager> Create(bool enable_impeller);

  virtual ~Manager();

  // Whether the manager is currently valid.
  bool IsValid() const;

  // Creates an EGLSurface wrapper and backing DirectX 11 SwapChain
  // associated with window, in the appropriate format for display.
  // HWND is the window backing the surface. Width and height represent
  // dimensions surface is created at.
  //
  // After the surface is created, |SetVSyncEnabled| should be called on a
  // thread that can bind the |render_context_|.
  virtual bool CreateSurface(HWND hwnd, EGLint width, EGLint height);

  // Resizes backing surface from current size to newly requested size
  // based on width and height for the specific case when width and height do
  // not match current surface dimensions. Target represents the visual entity
  // to bind to.
  //
  // This binds |render_context_| to the current thread.
  virtual void ResizeSurface(HWND hwnd,
                             EGLint width,
                             EGLint height,
                             bool enable_vsync);

  // queries EGL for the dimensions of surface in physical
  // pixels returning width and height as out params.
  void GetSurfaceDimensions(EGLint* width, EGLint* height);

  // Releases the pass-in EGLSurface wrapping and backing resources if not null.
  virtual void DestroySurface();

  // Check if the current thread has a context bound.
  bool HasContextCurrent();

  // Binds |render_context_| to the current rendering thread and to the draw and
  // read surfaces returning a boolean result reflecting success.
  virtual bool MakeCurrent();

  // Swaps the front and back buffers of the DX11 swapchain backing surface if
  // not null.
  virtual bool SwapBuffers();

  // Creates a |EGLSurface| from the provided handle.
  EGLSurface CreateSurfaceFromHandle(EGLenum handle_type,
                                     EGLClientBuffer handle,
                                     const EGLint* attributes) const;

  // Gets the |EGLDisplay|.
  EGLDisplay egl_display() const { return display_; };

  // If enabled, makes the current surface's buffer swaps block until the
  // v-blank.
  //
  // If disabled, allows one thread to swap multiple buffers per v-blank
  // but can result in screen tearing if the system compositor is disabled.
  //
  // This binds |render_context_| to the current thread and makes the render
  // surface current.
  virtual void SetVSyncEnabled(bool enabled);

  // Gets the |ID3D11Device| chosen by ANGLE.
  bool GetDevice(ID3D11Device** device);

  // Get the EGL context used to render Flutter views.
  virtual Context* render_context() const;

  // Get the EGL context used for async texture uploads.
  virtual Context* resource_context() const;

 protected:
  // Creates a new surface manager retaining reference to the passed-in target
  // for the lifetime of the manager.
  explicit Manager(bool enable_impeller);

 private:
  // Number of active instances of Manager
  static int instance_count_;

  // Initialize the EGL display.
  bool InitializeDisplay();

  // Initialize the EGL configs.
  bool InitializeConfig(bool enable_impeller);

  // Initialize the EGL render and resource contexts.
  bool InitializeContexts();

  // Initialize the D3D11 device.
  bool InitializeDevice();

  void CleanUp();

  // Whether the manager was initialized successfully.
  bool is_valid_ = false;

  // EGL representation of native display.
  EGLDisplay display_ = EGL_NO_DISPLAY;

  // EGL framebuffer configuration.
  EGLConfig config_ = nullptr;

  // The EGL context used to render Flutter views.
  std::unique_ptr<Context> render_context_;

  // The EGL context used for async texture uploads.
  std::unique_ptr<Context> resource_context_;

  // Current render_surface that engine will draw into.
  EGLSurface surface_ = EGL_NO_SURFACE;

  // Requested dimensions for current surface
  EGLint surface_width_ = 0;
  EGLint surface_height_ = 0;

  // The current D3D device.
  Microsoft::WRL::ComPtr<ID3D11Device> resolved_device_ = nullptr;

  FML_DISALLOW_COPY_AND_ASSIGN(Manager);
};

}  // namespace egl
}  // namespace flutter

#endif  // FLUTTER_SHELL_PLATFORM_WINDOWS_EGL_MANAGER_H_