Applying matrix to SpriteBatch

Graphics
1

Okay folks, I am basically using this code: http://www.david-amador.com/2009/10/xna-camera-2d-with-zoom-and-rotation/ for my camera. Everything works fine, except when applying it to the SpriteBatch. I have a unit at position X:400 and Y:400 for testing. So technically when I start the program it should roughly be up there, my res is 1920x1080:

##########################

x

##########################
(doesn’t show, basically upper left)

But instead it ends up there:

##########################

x

##########################
(doesn’t show, basically lower right)

Is that expected behavior?

2

How are you using the camera exactly? And maybe share a screenshot so we can get a clearer picture of what’s going wrong.

3

I’m simply applying the new Vector through the move method. Moving the camera works fine. The problem is that the game STARTS out like that:

unit.png1920×1080 4.11 KB

As you can see, I am showing the coordinates, the upper ones are the screen coordinates, the lower ones the logical position, so they are the same.

okay. I am drawing it like this:

- spriteBatch.Begin(SpriteSortMode.BackToFront,
_ null, null, null, null, null,
_ cam.Get_transformation(GraphicsDevice));_

_ foreach (Unit u in game_manager.unit_list)_
_ {_
_ _
_ u.Draw();_ ===> at Vector2(400,400)
_ }_
- spriteBatch.End();

Test-wise the unit is supposed to appear at X400, Y400 and since the camera has not moved game position and screen position should be congruent. I’m wondering, previously I was using Monkey X and it worked fine there. I’m just confused… perhaps I am missing something. But there should nothing happen but applying the translate to the logical position to represent it on the screen position… nothing fancy going on :joy:

Here is the calculation of the matrix from the linked code:

     transform = Matrix.CreateTranslation(new Vector3(-pos.X, -pos.Y, 0)) *
                                     Matrix.CreateRotationZ(Rotation) *
                                     Matrix.CreateScale(new Vector3(Zoom, Zoom, 1))* Matrix.CreateTranslation(new Vector3(graphicsDevice.Viewport.Width * 0.5f, graphicsDevice.Viewport.Height * 0.5f, 0));

Is there something wrong with the viewport * 0.5?