EmscriptenFrameRateController.h

#pragma once

#include "Types.h"
#include "EmscriptenTypes.h"

namespace Eegeo
{
    namespace Emscripten
    {
        class EmscriptenFrameRateController : private Eegeo::NonCopyable
        {
        public:
            static EmscriptenFrameRateController* Create(
                const EmscriptenFrameRateOptions& emscriptenFrameRateOptions
            );

            void Update(double inputIdleTimeSeconds);
            void Pause();
            void Resume();

            bool IsNextFrameDue() const;
            bool IsPaused() const;
            float GetCurrentFrameDeltaSeconds() const;

            void SetTargetVSyncInterval(int targetVSyncInterval);
            void SetThrottledTargetFrameInterval(int throttledTargetFrameIntervalMS);
            void SetIdleSecondsBeforeThrottle(float idleSecondsBeforeThrottle);
            void SetThrottleWhenIdleEnabled(bool enabled);
            void CancelThrottle();

        private:
            EmscriptenFrameRateController(
                int targetVSyncInterval,
                int throttledTargetFrameIntervalMS,
                float idleTimeoutSeconds,
                bool throttleWhenIdleEnabled,
                bool loggingEnabled
            );

            bool ShouldThrottle(double idleTimeSeconds) const;

            int m_targetVSyncInterval;
            int m_throttledTargetFrameIntervalMS;
            float m_idleSecondsBeforeThrottle;
            bool m_throttleWhenIdleEnabled;
            bool m_loggingEnabled;
            bool m_isInitialized;
            bool m_isThrottled;
            bool m_isPaused;
            bool m_isNextFrameDue;
            double m_previousFrameTimeMilliseconds;
            float m_currentFrameDeltaSeconds;
            double m_timeSinceCancelThrottle;
            int m_frameCount;
        };
    }
}