gfx/gl/GLScreenBuffer.h

   1 /* -*- Mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 4; -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 /* GLScreenBuffer is the abstraction for the "default framebuffer" used
   7  * by an offscreen GLContext. Since it's only for offscreen GLContext's,
   8  * it's only useful for things like WebGL, and is NOT used by the
   9  * compositor's GLContext. Remember that GLContext provides an abstraction
  10  * so that even if you want to draw to the 'screen', even if that's not
  11  * actually the screen, just draw to 0. This GLScreenBuffer class takes the
  12  * logic handling out of GLContext.
  13  */
  14
  15 #ifndef SCREEN_BUFFER_H_
  16 #define SCREEN_BUFFER_H_
  17
  18 #include "GLTypes.h"
  19 #include "mozilla/gfx/Point.h"
  20 #include "mozilla/UniquePtr.h"
  21
  22 #include <functional>
  23 #include <queue>
  24 #include <memory>
  25
  26 namespace mozilla {
  27 namespace gl {
  28
  29 class SharedSurface;
  30 class SurfaceFactory;
  31 class SwapChain;
  32
  33 class SwapChainPresenter final {
  34   friend class SwapChain;
  35
  36   SwapChain* mSwapChain;
  37   std::shared_ptr<SharedSurface> mBackBuffer;
  38
  39  public:
  40   explicit SwapChainPresenter(SwapChain& swapChain);
  41   ~SwapChainPresenter();
  42
  43   const auto& BackBuffer() const { return mBackBuffer; }
  44
  45   std::shared_ptr<SharedSurface> SwapBackBuffer(std::shared_ptr<SharedSurface>,
  46                                                 bool& aSuccess);
  47   GLuint Fb() const;
  48 };
  49
  50 // -
  51
  52 class SwapChain final {
  53   friend class SwapChainPresenter;
  54
  55  public:
  56   UniquePtr<SurfaceFactory> mFactory;
  57
  58  private:
  59   std::queue<std::shared_ptr<SharedSurface>> mPool;
  60   std::shared_ptr<SharedSurface> mFrontBuffer;
  61   std::function<void()> mDestroyedCallback;
  62
  63  public:
  64   std::shared_ptr<SharedSurface>
  65       mPrevFrontBuffer;  // Hold this ref while it's in-flight.
  66  private:
  67   SwapChainPresenter* mPresenter = nullptr;
  68
  69  public:
  70   SwapChain();
  71   virtual ~SwapChain();
  72
  73   void ClearPool();
  74   bool StoreRecycledSurface(const std::shared_ptr<SharedSurface>& surf);
  75   const auto& FrontBuffer() const { return mFrontBuffer; }
  76   UniquePtr<SwapChainPresenter> Acquire(const gfx::IntSize&, gfx::ColorSpace2);
  77
  78   void SetDestroyedCallback(std::function<void()>&& aDestroyedCallback) {
  79     MOZ_ASSERT(!mDestroyedCallback);
  80     mDestroyedCallback = std::move(aDestroyedCallback);
  81     mPool = {};
  82   }
  83 };
  84
  85 }  // namespace gl
  86 }  // namespace mozilla
  87
  88 #endif  // SCREEN_BUFFER_H_