RenderStatistics.h

#pragma once
 
// Standard.
#include <chrono>
#include <optional>
#include <atomic>
#include <mutex>
 
namespace ne {
    class RenderStatistics {
        // Renderer will update statistics.
        friend class Renderer;
 
    public:
        RenderStatistics() = default;
 
        RenderStatistics(const RenderStatistics&) = delete;
        RenderStatistics& operator=(const RenderStatistics&) = delete;
 
        size_t getFramesPerSecond() const;
 
        size_t getLastFrameDrawCallCount() const;
 
        size_t getLastFrameCulledMeshCount() const;
 
        size_t getLastFrameCulledLightCount() const;
 
        float getTimeSpentLastFrameWaitingForGpu() const;
 
        float getTimeSpentLastFrameOnFrustumCullingMeshes() const;
 
        float getTimeSpentLastFrameOnFrustumCullingLights() const;
 
    private:
        struct FramesPerSecondInfo {
            std::chrono::steady_clock::time_point timeAtLastFpsUpdate;
 
            size_t iPresentCountSinceFpsUpdate = 0;
 
            size_t iFramesPerSecond = 0;
        };
 
        struct FpsLimitInfo {
            std::chrono::steady_clock::time_point frameStartTime;
 
            std::optional<double> optionalTargetTimeToRenderFrameInNs = {};
        };
 
        struct TaskTimeInfo {
            float timeSpentLastFrameWaitingForGpuInMs = 0.0F;
 
            float timeSpentLastFrameOnFrustumCullingMeshesInMs = 0.0F;
 
            float timeSpentLastFrameOnFrustumCullingLightsInMs = 0.0F;
        };
 
        struct Counters {
            size_t iLastFrameCulledMeshesCount = 0;
 
            size_t iLastFrameCulledLightsCount = 0;
 
            size_t iLastFrameDrawCallCount = 0;
        };
 
        struct FrameTemporaryStatistics {
            FrameTemporaryStatistics();
 
            std::pair<std::mutex, float> mtxFrustumCullingMeshesTimeInMs;
 
            std::pair<std::mutex, float> mtxFrustumCullingLightsTimeInMs;
 
            std::atomic<size_t> iCulledMeshCount{0};
 
            std::atomic<size_t> iCulledLightCount{0};
 
            std::atomic<size_t> iDrawCallCount{0};
        };
 
        void saveAndResetTemporaryFrameStatistics();
 
        FramesPerSecondInfo fpsInfo;
 
        FpsLimitInfo fpsLimitInfo;
 
        TaskTimeInfo taskTimeInfo;
 
        Counters counters;
 
        FrameTemporaryStatistics frameTemporaryStatistics;
    };
}