Comments on: XNA Game Engine Tutorial Series #3 – Utilities, Components, Camera, Actor

By: Jay

Jay — Fri, 11 Nov 2011 20:28:59 +0000

Maybe I should have read the comment above mine. Lol. That fixed it.

By: Jay

Jay — Fri, 11 Nov 2011 20:27:46 +0000

Hello all, I was going through this tutorial when I ran into some problems. I tried downloading the sample code to see if it would run and it does, but before anything is displayed on the screen I get the following error:

System.NullReferenceException was unhandled

on this line:

effect.Parameters["View"].SetValue(camera.View);

from the Actor.cs class

Does anyone know why this is happening?

By: biggs

biggs — Tue, 24 May 2011 05:57:22 +0000

replace those parameter lines with:

effect.World = transforms[mesh.ParentBone.Index] * world;
effect.View = camera.View;
effect.Projection = camera.Projection;

not sure if this is a change in xna 4.0 or what but that should solve your problems.

By: Anthony Lisowski

Anthony Lisowski — Thu, 10 Feb 2011 02:23:44 +0000

So, I am using this tutorial to learn XNA and so far its been really helpful. However im having a few problems. When I try to run the project I get errors on the following lines

effect.Parameters["View"].SetValue(camera.View);
effect.Parameters["Projection"].SetValue(camera.Projection);

“Object reference not set to an instance of an object.”

If I make sure effect.Parameters["View"] is not null before attempting it will get render the scene.

However my other issue is that the the model is rendering as a flat graphic. And it doesnt matter what information I set for its position, the camera position or the camera target, the same flat graphic appears with the same dimension. Any idea what is happening?

By: Sam Fisher

Sam Fisher — Wed, 12 Jan 2011 02:20:23 +0000

If you are getting a error CS0246: The type or namespace name ‘Exception’ could not be found (are you missing a using directive or an assembly reference?)

Just include “using System;” above “user Microsoft.Xna.Framework;” had me for a few minutes.

Great tutorials.