GRAPHICS: Add FPS / frame time calculation

src/graphics/graphics.cpp

@@ -337,6 +337,27 @@ bool GraphicsManager::setGamma(float gamma) {
 	return true;
 }
 
+double GraphicsManager::getAverageFrameTime() const {
+	if (!_renderer)
+		return 0.0;
+
+	return _renderer->getAverageFrameTime();
+}
+
+double GraphicsManager::getAverageFPS() const {
+	if (!_renderer)
+		return 0.0;
+
+	return _renderer->getAverageFPS();
+}
+
+bool GraphicsManager::getRenderStatistics(double &averageFrameTime, double &averageFPS) const {
+	if (!_renderer)
+		return false;
+
+	return _renderer->getRenderStatistics(averageFrameTime, averageFPS);
+}
+
 void GraphicsManager::renderScene() {
 	Common::enforceMainThread();
 

src/graphics/graphics.h

@@ -112,6 +112,11 @@ class GraphicsManager : public Common::Singleton<GraphicsManager> {
 	/** Set the overall gamma correction. */
 	bool setGamma(float gamma);
 
+	double getAverageFrameTime() const;
+	double getAverageFPS() const;
+
+	bool getRenderStatistics(double &averageFrameTime, double &averageFPS) const;
+
 	/** Render one complete frame of the scene. */
 	void renderScene();
 

src/graphics/renderer.cpp

@@ -69,6 +69,11 @@ class OgreLogger : public Ogre::LogListener {
 };
 
 class OgreAnimator : public Ogre::FrameListener {
+private:
+	static const uint kFrameTimeAverageCount = 5;
+
+	std::list<double> _frameTimes;
+
 public:
 	bool frameStarted(const Ogre::FrameEvent &event) {
 		Ogre::SceneManager *scene = Ogre::Root::getSingleton().getSceneManagerIterator().begin()->second;
@@ -77,11 +82,37 @@ class OgreAnimator : public Ogre::FrameListener {
 
 		OGRE_LOCK_MUTEX(scene->sceneGraphMutex);
 
+		_frameTimes.push_back(event.timeSinceLastFrame);
+		if (_frameTimes.size() > kFrameTimeAverageCount)
+			_frameTimes.pop_front();
+
 		for (Ogre::AnimationStateIterator anims = scene->getAnimationStateIterator(); anims.hasMoreElements(); anims.moveNext())
 			anims.current()->second->addTime(event.timeSinceLastFrame);
 
 		return true;
 	}
+
+	double getAverageFrameTime() const {
+		Ogre::SceneManager *scene = Ogre::Root::getSingleton().getSceneManagerIterator().begin()->second;
+		if (!scene)
+			return 0.0;
+
+		OGRE_LOCK_MUTEX(scene->sceneGraphMutex);
+
+		double average = 0.0;
+		for (std::list<double>::const_iterator f = _frameTimes.begin(); f != _frameTimes.end(); ++f)
+			average += *f;
+
+		return average / _frameTimes.size();
+	}
+
+	double getAverageFPS() const {
+		double averageFrameTime = getAverageFrameTime();
+		if (averageFrameTime <= 0.0)
+			return 0.0;
+
+		return 1.0 / averageFrameTime;
+	}
 };
 
 Renderer::Renderer(SDL_Window &screen, bool vsync, int fsaa) :
@@ -334,6 +365,32 @@ void Renderer::render() {
 	_root->renderOneFrame();
 }
 
+double Renderer::getAverageFrameTime() const {
+	if (!_animator)
+		return 0.0;
+
+	return _animator->getAverageFrameTime();
+}
+
+double Renderer::getAverageFPS() const {
+	if (!_animator)
+		return 0.0;
+
+	return _animator->getAverageFPS();
+}
+
+bool Renderer::getRenderStatistics(double &averageFrameTime, double &averageFPS) const {
+	if (!_sceneManager)
+		return false;
+
+	OGRE_LOCK_MUTEX(_sceneManager->sceneGraphMutex);
+
+	averageFrameTime = getAverageFrameTime();
+	averageFPS       = getAverageFPS();
+
+	return true;
+}
+
 bool Renderer::hasCapability(RenderCapability c) const {
 	switch (c) {
 		case kCapabilityS3TC:

src/graphics/renderer.h

@@ -71,6 +71,12 @@ class Renderer {
 	/** Render one frame. */
 	void render();
 
+	double getAverageFrameTime() const;
+	double getAverageFPS() const;
+
+	bool getRenderStatistics(double &averageFrameTime, double &averageFPS) const;
+
+
 private:
 	Common::UString _pluginDirectory; ///< Directory where the OGRE plugins can be found.