Avoiding game loop in XNA 4.0 - c#

I developing a simple 3D model viewer on XNA 4.0. Is there a way to avoid a infinite game loop with Draw and Update functions? I need render 3D graphics, but without infinite rendering of scene. I mean I need redraw the scene only then it really changed.

I suggest taking a look at how they're doing it in their samples:
App Hub - WinForms Series 1
App Hub - WinForms Series 2

Why exactly do you want this?
If you use a winforms application you have more control on your update and draw loop, but you also could render the scene to a texture first, and then stop rendering at all.

You are going to have to roll your own multi-threaded loop; if you stall either Update or Draw the other will get stalled too. Another consideration is that if your window gets obscured somehow (under non-DWM environments; a window overlapping it for instance) stalling the Draw will leave areas of your window unpainted.
If you want to go ahead with this; what you will do is start a Thread the first time Update gets called and subsequently use a ManualResetEvent to synchronise the two.
A far more robust option is to render your entire scene to a RenderTarget2D when the scene is updated; if the scene has not been altered since the last Update or Draw call simply render the RenderTarget2D instead of the whole scene. This is still an infinite loop, but it tends toward your requirement (even though it does not meet it).

This sort of scenario would be best solved by using WinForms or WPF as the host for your rendering system. I have worked with such systems before and I found using SlimDX with WPF Interop was my preferred solution. Using this approach allows for the addition of nice UI features provided by WPF, overlain on a 3D model rendered to a surface.

Related

Loading Multiple Scenes Additive Makes Compositor kicks in (Steam VR Unity)

I am having a issue where i suppose to load a large number of objects in my scene on an event,
so when ever i start loading these Scenesmy Vive/vr goes to compositor screen and it kinda flickers between my main scene and compositor screen
until my loading of Scenes is finished.
So my question is how to stop this flickering, i am happy to call the compositor screen till my Loading is completed and then it switch back to my Main scene or something like that which can solve this flickering issue
i have been searching around that how to call compositor screen on my own or how to stop it being called when my Loading is in progress but in vein.
any help would be much appreciated because i am out of ideas.
Thanks...
Flickering and showing compositor screen is generally caused by Unity not being able to Render a frame. I'm sure you will be able to find which object(s) (if any in particular) is causing a lag in the Profiler Tab.
I assume by "Loading" objects you mean Instancing them. If so, it depends:
a) If you instancing multiple identical objects - look up into GPU instancing methods
b) if the objects aren't unique, you may try to:
Load scene asynchronously
Place all (deactivated) objects on the first scene and instead of instancing or
loading new scene, just activate them. This will only increase initial loading
time.
Another things that you can use is:
Single Pass Stereo Rendering
use of ONLY or mostly baked lightning - which will SIGNIFICANTLY increase performance (that let me display in real time VR scene with model that counts more than 40 million vertices)
By default, SteamVR fades to grid whenever an app hangs. While of course it's ideal to keep your framerate above the threshold that would normally trigger this, there are many cases (such as loading scenes) where all the optimization in the world won't keep Unity from hanging long enough to trigger this issue.
Fortunately, this behavior can be disabled entirely! SteamVR Settings -> Developer -> Do not fade to grid when app hangs. This setting can be also be changed in the steamvr.vrsettings file which can be found using vrpathreg.exe. There, set steamvr.doNotFadeToGrid to true. This file is modified by the SteamVR Settings interface as well, but accessing it via the file directly allows you to modify settings for your target devices from within a game installer, for example.
Unfortunately as of now there isn't a way to configure this on a per-app basis, meaning the behavior will be turned off for all SteamVR apps on a user's machine. Tweaking this setting comes with the caveat that low framerates make users feel sick and the fade-to-grid feature prevents this from happening. However, in my experience, the feature is a nuisance that detracts from immersion far more than a temporary dip in framerate as long as you're following performance best practices, and if framerate is dropping anyway, this fade to grid feature causes intense flickering that's just as uncomfortable as low framerate.

Render target for each scene, for transitions

I'm trying to come up with a general concept for transitions, without having to include any specific code inside the actual scene. In all the samples I've seen so far the scenes handle that stuff themselves. Like a fade in/out, where the scenes have to adjust their draw method, for the correct transparency. But not only would this be annoying to have in every scene, with multiple kinds of transitions you'd get cluttered code pretty fast.
So I've been thinking. The only way I could come up with to support this, and more complicated transitions, without handling it in the scene itself, are render targets for each scene. The render target would be set from the scene manager before calling the draw method. After draw the render target would get reset to the render target of the manager, and the scene's texture would get drawn with information about the current transition. Without clearing the manager texture more scenes would follow, if more have to be drawn. This way you could do pretty much anything (transition wise), the scenes would be completely independent of each other, and you wouldn't need a single line of transition code in the actual scenes. (For reference, there are various transition types I'd like to be able to do. Not only fades, but also shader effects, moving one scene in while the current one is "pushed away", etc., involving one or multiple scenes.)
Well, that's my theory. Here comes my question: Does this sound like a viable plan? Is this the way to go? I've read about performance problems when switching rendering targets too frequently, and other problems, which is the main reason I'm hesitating to implement this. But so far I couldn't think of or find a better method. Although I think it shouldn't make a difference, for the moment I only care about 2D (mentioned just in case).
That, in general is a sound approach, but beware render target switching costs. Also, if each scene were to be animated at the time of transition, you'd be rendering two scenes at the same time into two different rendertargets and then compositing the results on screen.

is there a way to make a 3D game in winforms or WPF in C#?

I'm thinking about making a 3D point and click game, is it possible to make one in winforms or WPF? I don't need any physics or anything all I need is to make the application render 3D objects. I know that I can use XNA but if I do then I will have to relearn almost everything again. My third approach would be to make the scenes in a 3D game engine and then print the screen and then load it as a image. Any suggestion would be appreciated.
There's a big difference between a 3D game, and just letting players interact with a rendered image.
Your approach of loading a pre-rendered image is possible to do in both Winforms and WPF. You would just need to capture click events on the image and check the location against your list of active areas. Then just handle what needed to be done, ie: move to the next area, activate item, etc.
Edit from comment:
It's not so much which is friendlier. You can host an XNA viewport in Winforms/WPF. It's more about how you want your game to work. If you never have moving 3D scenes, XNA is overkill, and images will work just fine.
If you want dynamic scenes, you'll need to be able to render them on the fly. Then, XNA makes more sense. It is a lot more work though compared to just displaying images.
If you just want to show pre-rendered 3d images in your game, why not create them using a real 3d graphics tool, such as 3D Studio Max or Maya (or a free one, such as Blender)? It sounds like there's no need for actually rendering the 3d scenes in a game engine at all.

Buidling an XNA tile editor

I'm writing a tile editor for a game and would like to be able to select which level file to open. Once open I would load the level into an XNA window and click to add/remove tiles to the level. When the editing is finished I would save the file layout back to the original file.
Currently I don't see a way to integrate windows forms and XNA. Is this even possible?
When I was working on a small, "2.5D" isometric game in XNA, I found it worth while to also have a separate WinForms version that would just render a 2D top-down view using GDI. This was due to my inexperience with XNA and my (relative) comfort using WinForms.
This approach also had the useful side-effect of enforcing separation between logic and rendering code. It made it easier (for me, at least) to test changes without having to worry about how to deal with the XNA rendering aspects.
It may not be exactly what you had in mind, but it might be something to consider.
WinForms and Xna can cooperate, but it's not recommended to use Xna's built in Game class with WinFroms. There are two samples demonstrating it:
http://xbox.create.msdn.com/en-US/education/catalog/sample/winforms_series_1
http://xbox.create.msdn.com/en-US/education/catalog/sample/winforms_series_2

Spinning a 3D model in C#

How do I take a 3D model that I created in 3D Studio Max and put it into my Winform C# program and make it spin? I'd prefer not to use DirectX if possible. I don't want anything complex. I simply want my model to rotate along the X axis. Thats it.
Thanks
You should use a 3D rendering engine for C#
Something like
http://axiom3d.net/wiki/index.php/Main_Page
http://www.codeproject.com/KB/GDI-plus/exoengine.aspx
http://irrlicht.sourceforge.net/features.html
http://freegamedev.net/wiki/Free,_cross-platform,_real-time_3D_engines
I have never used any rendering engines but for your requirements (letting the user move the object) i think a 3D engine would do. But perhaps this is over kill
If you want it to be dynamic, then the simplest option would be to render out an animation of the object rotating, but make each frame a separate file. Then you just show the correct image based on how the user is dragging the mouse. If the user drags the mouse to the right, then increment the frame and show the next image. If moving to the left, decrement the frame.
For something non interactive:
Export the animation to an AVI and embed that in your form:
Embedding Video in a WinForms app
It's not really what I'd recommend, but it's an alternative to creating an animated gif.
For something partially interactive (i.e. allowing limited movement):
I've seen QuickTime movies that you can control with the mouse. There's an example on this page. It's not 3D though.
For something fully interactive:
You need a 3D rendering engine of some sort and that does (usually) require DirectX or OpenGL. However, if you're only dealing with simple objects you might (repeat might) get away with a software renderer.

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