What is easiest way to implement animated startup/load screen?

[slapin]

What is easiest way to implement animated startup/load screen?
I need it to hide some unaesthetic 3D scene stuff behind.

[rpgplayerrobin]

If you are using background loading of your resources at startup, I think you can just render normally (with an FPS limit of course, otherwise you may fry some graphic cards!) until the background resources have been completely loaded.

If you are not using background loading, you can use the resource group listener to listen to when a resource has been loaded, and then just trigger a render (with an FPS limit as well).
Here is a short class to handle that:

Code: Select all

class CResourceGroupListener : public Ogre::ResourceGroupListener
{
public:
	CResourceGroupListener();
	~CResourceGroupListener();

// ResourceGroupListener
void resourceGroupScriptingStarted(const Ogre::String& groupName, size_t scriptCount);
void scriptParseStarted(const Ogre::String& scriptName, bool& skipThisScript);
void scriptParseEnded(const Ogre::String& scriptName, bool skipped);
void resourceGroupScriptingEnded(const Ogre::String& groupName);
void resourceGroupLoadStarted(const Ogre::String& groupName, size_t resourceCount);
void resourceLoadStarted(const Ogre::ResourcePtr& resource);
void resourceLoadEnded();
void resourcePrepareStarted(const ResourcePtr& resource);
void resourceCreated(const ResourcePtr& resource);
void worldGeometryStageStarted(const Ogre::String& description);
void worldGeometryStageEnded();
void resourceGroupLoadEnded(const Ogre::String& groupName);
};

CResourceGroupListener::CResourceGroupListener()
{
}

CResourceGroupListener::~CResourceGroupListener()
{
}

void CResourceGroupListener::resourceGroupScriptingStarted(const Ogre::String& groupName, size_t scriptCount)
{
	// Update loading screen
	if (app->m_GUIManager->m_screen_loadingScreen)
		app->m_GUIManager->m_screen_loadingScreen->UpdateLoading();
}

void CResourceGroupListener::scriptParseStarted(const Ogre::String& scriptName, bool& skipThisScript)
{
	// Update loading screen
	if (app->m_GUIManager->m_screen_loadingScreen)
		app->m_GUIManager->m_screen_loadingScreen->UpdateLoading();
}

void CResourceGroupListener::scriptParseEnded(const Ogre::String& scriptName, bool skipped)
{
	// Update loading screen
	if (app->m_GUIManager->m_screen_loadingScreen)
		app->m_GUIManager->m_screen_loadingScreen->UpdateLoading();
}

void CResourceGroupListener::resourceGroupScriptingEnded(const Ogre::String& groupName)
{
	// Update loading screen
	if (app->m_GUIManager->m_screen_loadingScreen)
		app->m_GUIManager->m_screen_loadingScreen->UpdateLoading();
}

void CResourceGroupListener::resourceGroupLoadStarted(const Ogre::String& groupName, size_t resourceCount)
{
	// Update loading screen
	if (app->m_GUIManager->m_screen_loadingScreen)
		app->m_GUIManager->m_screen_loadingScreen->UpdateLoading();
}

void CResourceGroupListener::resourceLoadStarted(const Ogre::ResourcePtr& resource)
{
	// Update loading screen
	if (app->m_GUIManager->m_screen_loadingScreen)
		app->m_GUIManager->m_screen_loadingScreen->UpdateLoading();
}

void CResourceGroupListener::resourceLoadEnded()
{
	// Update loading screen
	if (app->m_GUIManager->m_screen_loadingScreen)
		app->m_GUIManager->m_screen_loadingScreen->UpdateLoading();
}

void CResourceGroupListener::resourcePrepareStarted(const ResourcePtr& resource)
{
	// Update loading screen
	if (app->m_GUIManager->m_screen_loadingScreen)
		app->m_GUIManager->m_screen_loadingScreen->UpdateLoading();
}

void CResourceGroupListener::resourceCreated(const ResourcePtr& resource)
{
	// Update loading screen
	if (app->m_GUIManager->m_screen_loadingScreen)
		app->m_GUIManager->m_screen_loadingScreen->UpdateLoading();
}

void CResourceGroupListener::worldGeometryStageStarted(const Ogre::String& description)
{
	// Update loading screen
	if (app->m_GUIManager->m_screen_loadingScreen)
		app->m_GUIManager->m_screen_loadingScreen->UpdateLoading();
}

void CResourceGroupListener::worldGeometryStageEnded()
{
	// Update loading screen
	if (app->m_GUIManager->m_screen_loadingScreen)
		app->m_GUIManager->m_screen_loadingScreen->UpdateLoading();
}

void CResourceGroupListener::resourceGroupLoadEnded(const Ogre::String& groupName)
{
	// Update loading screen
	if (app->m_GUIManager->m_screen_loadingScreen)
		app->m_GUIManager->m_screen_loadingScreen->UpdateLoading();
}

Then, you add it to your resource groups that you load before they are actually loaded

Code: Select all

CResourceGroupListener* tmpListener = new CResourceGroupListener();
tmpResourceGroupManager.addResourceGroupListener(tmpListener);

tmpResourceGroupManager.initialiseResourceGroup(m_groupName);
tmpResourceGroupManager.loadResourceGroup(m_groupName, true, true);

tmpResourceGroupManager.removeResourceGroupListener(tmpListener);
delete tmpListener;

[slapin]

Thanks a lot for examples, I see the idea. But I need help with actual screen implementation. I need example with something which will be drawn over 3D
scene and hide it, and it would be nice to be able to draw some text and animate it for user to not think something hung...
I tried with ImGUI but it requires drawing each frame which is not possible in this case as I want to actually let the main thread freezes at that moment,
I need something I'd draw and keep at that until I update it and destroy it later.

[rpgplayerrobin]

I guess this is then a UI issue?

For my loading screen, I simply render a UI with text, which hides the 3D scene behind (but there is no reason for me to hide the 3D scene since there is nothing there anyway most of the time, since the loading screen is mostly used while loading resources, not much while creating them, since creating them is almost done instantly anyway).

To render the loading screen, I simply use renderOneFrame on the Ogre root object, like any other render.

[slapin]

I think there should be a way to do it in GUI-independent way...

[sercero]

Well you either give the user a static screen with text (like Dark Souls where they show item descriptions for you to read) or you make something animated but choppy, so that the background thread is able to update.

[paroj]

see the SampleBrowser:
https://github.com/OGRECave/ogre/blob/9 ... ys.h#L1100