Question

I am using both primitives and sprites in an XNA project. I draw my primitives using this code (a summary, not verbatim from my project):

transmatrix = Matrix.CreateTranslation(v23(-pos)) * Matrix.CreateScale(scale, -scale, 1f) * Matrix.CreateTranslation(v23(offset));   
basicEffect.World = transmatrix;
basicEffect.View = Matrix.CreateLookAt(new Vector3(0.0f, 0.0f, 1.0f), Vector3.Zero, Vector3.Up);
basicEffect.Projection = Matrix.CreateOrthographicOffCenter(0, (float)GraphicsDevice.Viewport.Width, (float)GraphicsDevice.Viewport.Height, 0, 1.0f, 1000.0f);
basicEffect.Begin();
//draw primitives blah blah
basicEffect.End();
 spritebatch.Begin(SpriteBlendMode.None, SpriteSortMode.Immediate, SaveStateMode.None, transmatrix);
//draw sprites blah blah
spritebatch.end()

if I have

transmatrix = Matrix.CreateTranslation(v23(-pos)) * Matrix.CreateScale(scale, scale, 1f) * Matrix.CreateTranslation(v23(offset)); 

both the primitives and the sprites draw (but y is the inverse of what I want).
if I have

transmatrix = Matrix.CreateTranslation(v23(-pos)) * Matrix.CreateScale(scale, -scale, 1f) * Matrix.CreateTranslation(v23(offset)); 

The primitives draw correctly, but the sprites don’t draw at all. What am I missing? I have tried messing around with lots of different things but nothing seems to work.

Answer 1

SpriteBatch sets up its own “camera” using its own parameters. To scale your camera, do this:

basicEffect.View = Matrix.CreateScale(1.0f, -1.0, 1.0f) * Matrix.CreateLookAt(new Vector3(0.0f, 0.0f, 1.0f), Vector3.Zero, Vector3.Up);

Or you could just create a different matrix for the spritebatch.

Alternatively, you could pass in your BasicEffect to SpriteBatch:

http://msdn.microsoft.com/en-us/library/ff433700.aspx