RhiPreviewWidget.hpp

#pragma once
#include <ossia/gfx/port_index.hpp>
 
#include <QPointer>
#include <QWidget>
 
#include <score_plugin_gfx_export.h>
 
#include <cstdint>
#include <functional>
#include <memory>
 
struct QRhiReadbackResult;
 
namespace score::gfx
{
struct Graph;
struct BackgroundNode;
}
 
namespace Gfx
{
class GfxContext;
using port_index = ossia::gfx::port_index;
 
class SCORE_PLUGIN_GFX_EXPORT RhiPreviewWidget : public QWidget
{
public:
  explicit RhiPreviewWidget(QWidget* parent = nullptr);
  ~RhiPreviewWidget() override;
 
  void useGraph(
      score::gfx::Graph* graph,
      std::function<void(score::gfx::BackgroundNode&)> onAttached,
      std::function<void(score::gfx::BackgroundNode&)> onAboutToDetach);
 
  void useContext(GfxContext* ctx, port_index producer);
  void setProducer(port_index producer);
 
protected:
  void paintEvent(QPaintEvent* ev) override;
  void resizeEvent(QResizeEvent* ev) override;
  void timerEvent(QTimerEvent* ev) override;
 
private:
  void attach();
  void detach();
 
  enum class Backend
  {
    None,
    Graph,
    Context
  } m_backend{Backend::None};
 
  // Graph backend
  score::gfx::Graph* m_graph{};
  std::function<void(score::gfx::BackgroundNode&)> m_onAttached;
  std::function<void(score::gfx::BackgroundNode&)> m_onAboutToDetach;
 
  // Context backend
  // QPointer, not a raw pointer: an inspector widget can be destroyed after
  // the GfxContext (a queued DeferredDelete outliving ~DocumentPlugin), and
  // detach() then calls into it. QPointer makes the existing null check hold.
  QPointer<GfxContext> m_ctx;
  port_index m_producer{-1, -1};
  int32_t m_screenNodeId{-1};
  bool m_edgeConnected{false};
 
  std::shared_ptr<QRhiReadbackResult> m_readback;
  score::gfx::BackgroundNode* m_node{};  // owned by m_graph or m_ctx after attach
 
  score::gfx::BackgroundNode* liveNode() const noexcept
  {
    if(!m_node)
      return nullptr;
    if(m_backend == Backend::Context && !m_ctx)
      return nullptr; // owner already gone; m_node is dangling
    return m_node;
  }
  int m_timerId{};
};
}