GpuTiming.hpp

#pragma once
#include <score_plugin_gfx_export.h>
 
#include <QtGui/private/qrhi_p.h>
 
#include <array>
#include <cstdint>
#include <mutex>
#include <string>
#include <vector>
 
namespace score::gfx
{
class SCORE_PLUGIN_GFX_EXPORT GpuTimings
{
public:
  static constexpr int kHistorySize = 64;
 
  struct Entry
  {
    std::string name;
    double last_ms{0.0};
    double mean_ms{0.0};
    double max_ms{0.0};
    std::array<double, kHistorySize> history{};
    int history_index{0};
    int sample_count{0};   // capped at kHistorySize; used to avoid cold-start bias
    int frames_since_observed{0};
  };
 
  GpuTimings() = default;
  GpuTimings(const GpuTimings&) = delete;
  GpuTimings& operator=(const GpuTimings&) = delete;
 
  void record(std::string_view name, double ms) noexcept;
 
  void tickFrame() noexcept;
 
  std::vector<Entry> snapshot() const;
 
  void reset() noexcept;
 
private:
  static constexpr int kStaleThreshold = 120;   // drop entries after 2s at 60fps
 
  mutable std::mutex m_mutex;
  std::vector<Entry> m_entries;
};
 
class SCORE_PLUGIN_GFX_EXPORT ScopedGpuTimer
{
public:
  ScopedGpuTimer(
      QRhiCommandBuffer& cb, GpuTimings& timings, std::string_view name);
  ~ScopedGpuTimer();
 
  ScopedGpuTimer(const ScopedGpuTimer&) = delete;
  ScopedGpuTimer& operator=(const ScopedGpuTimer&) = delete;
 
private:
  QRhiCommandBuffer& m_cb;
  GpuTimings& m_timings;
  std::string m_name;
};
 
} // namespace score::gfx