Hi, I've recently made the move from 2D XNA to 3D. I've been playing around trying to create a basic 3D world as practice; I just plan to have a camera, some terrain and an avatar.

I took a look at the generated geometry sample found at http://creators.xna.com/en-GB/sample/generatedgeometry and have been attempting to use it along with my own camera I made.  I've been having two problems; the first is a strange kind of stretching of the texture (http://www.jason-mitchell.com/images/textureStretch.JPG) and the second is that some of my terrain is appearing see through and terrain that should be blocked from site is visible (http://www.jason-mitchell.com/images/renderError.JPG).

The TerrainProcessor has been copied exactly from the sample and I have also tried a solution from a book which has the exact same problems which leads me to think that the problem lies elsewhere.

Here is my drawing code:


As mentioned previously,  the terrain processor code is exactly the same as in the Generated Geometry sample.

Does anyone know why this happens and how to solve it?

Thanks

It looks like your texture wrap and depth buffer render states are being set to something other than what you want. Are you drawing using a SpriteBatch or setting render states manually? See this if you are.

Ah, I had a game component that I was using to render debug information to the screen using a SpriteBatch, once I removed this it works perfectly!  From what I've read on your link, if I am combining the two, then I will need to set the render states manually?

hi jmitch,

yes.  As I gather, this is a pretty common issue when getting started with XNA.  All the changes you make to the renderstates are 'stored' on the graphics device and used when rendering, and they remain until you set them to something else (and I think they are 'reset' to defaults when present is called on the device?).  This means if you render an object to the screen after you have used the spritebatch to render something, then you will have to change all the renderstates back.

You can do this in a few ways, such as:

• Either manually change the renderstates back to the 'defaults' after using the sprite batch.
• Use the RenderState class to store all the renderstates before you use the SpriteBatch, and then set them back on the device after you have finished using the SpriteBatch.
• Or before you draw any objects with the GraphicsDevice, explicitly set the renderstates used when rendering the 'object'.

I did quite a bit of searching and didn't really come up with this information anywhere else.  I couldn't find anywhere that told me straight up about it; all the tutorials and samples that served as an introduction to 3D XNA that I had looked at didn't mention this.

I modified my draw code to the following so it would work along with the SpriteBatch in my game component:


This works fine for the purposes of what I'm doing, but I would imagine the better way to go about this would be to use your second suggestion.

hi jmitch,

That's a very good point!  I will probably continue doing it as I am now then, or create a method to set the render states as you have done. Thanks a lot!