cube/fuchsia/flatland_view.h

// Copyright 2022 The Fuchsia 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 THIRD_PARTY_VULKAN_TOOLS_CUBE_FUCHSIA_FLATLAND_VIEW_H_
#define THIRD_PARTY_VULKAN_TOOLS_CUBE_FUCHSIA_FLATLAND_VIEW_H_

#include <fuchsia/ui/app/cpp/fidl.h>
#include <fuchsia/ui/composition/cpp/fidl.h>
#include <fuchsia/ui/views/cpp/fidl.h>
#include <lib/fidl/cpp/binding_set.h>
#include <lib/fit/function.h>
#include <lib/sys/cpp/component_context.h>
#include <lib/syslog/cpp/macros.h>

#include <memory>

// This class provides a convenient wrapper around the scenic fidl apis needed to get a Flatland
// View. Only SDK available constructs should be used so that this code may be leveraged by Vulkan
// applications built with the SDK.
class FlatlandView {
  public:
    using ResizeCallback = fit::function<void(uint32_t width, uint32_t height)>;

    static std::unique_ptr<FlatlandView> Create(sys::ComponentContext* context,
                                                fuchsia::ui::views::ViewCreationToken view_creation_token,
                                                ResizeCallback resize_callback);

    explicit FlatlandView(ResizeCallback resize_callback);

    zx::channel TakeChildViewCreationToken() {
        FX_DCHECK(child_view_creation_token_.is_valid());
        return std::move(child_view_creation_token_);
    }

    bool Init(sys::ComponentContext* context, fuchsia::ui::views::ViewCreationToken view_creation_token);

  private:
    void OnGetLayout(fuchsia::ui::composition::LayoutInfo info);
    void OnFlatlandError(fuchsia::ui::composition::FlatlandError error);
    void Present();
    void OnNextFrameBegin(fuchsia::ui::composition::OnNextFrameBeginValues values);

    fuchsia::ui::composition::FlatlandPtr flatland_;
    fuchsia::ui::composition::ParentViewportWatcherPtr parent_viewport_watcher_;

    zx::channel viewport_creation_token_;
    zx::channel child_view_creation_token_;
    ResizeCallback resize_callback_;

    uint32_t present_credits_ = 1;
    bool pending_present_ = false;

    friend class FlatlandViewTest;
};

class FlatlandViewProviderService : public fuchsia::ui::app::ViewProvider {
  public:
    using CreateView2Callback = fit::function<void(fuchsia::ui::app::CreateView2Args args)>;

    FlatlandViewProviderService(sys::ComponentContext* context, CreateView2Callback create_view_callback);

    // fuchsia::ui::app::ViewProvider methods.
    void CreateViewWithViewRef(zx::eventpair view_token, fuchsia::ui::views::ViewRefControl view_ref_control,
                               fuchsia::ui::views::ViewRef view_ref) override;
    void CreateView2(fuchsia::ui::app::CreateView2Args args) override;

  private:
    void HandleViewProviderRequest(fidl::InterfaceRequest<fuchsia::ui::app::ViewProvider> request);

    CreateView2Callback create_view_callback_;
    fidl::BindingSet<ViewProvider> bindings_;
};

#endif  // THIRD_PARTY_VULKAN_TOOLS_CUBE_FUCHSIA_FLATLAND_VIEW_H_