xna在固定屏幕坐标上将3d对象显示为2d

Question

helllo, I'm trying to create a minecraft-like inventory which renders items and blocks on the screen in different slots. I have an array of vertices of a block and I want to draw it at a spesific screen coordinates at a spesific size.

BTW, this is the code I'm currently using, it is working but I can't deteminate a spesific position or a size:

 Vector2 coord = new Vector2(-4, 0); //Screen coord.
 int distance = 20; //Distance of the camera from the block(control the size).

  BlockRenderer.basicTextureEffect.View = Matrix.Identity * Matrix.CreateLookAt(new Vector3(-distance, distance * 0.6f, -distance), Vector3.One / 2, Vector3.Up) *  Matrix.CreateTranslation(coord.X, coord.Y, 0);
  BlockRenderer.basicTextureEffect.CurrentTechnique.Passes[0].Apply();
  graphics.GraphicsDevice.DrawUserPrimitives(PrimitiveType.TriangleList, vertex, 0, vertex.Length / 3);

thank you for your help!

Answer 1

Your matrixs need to be swapped. You want the identity matrix to be at the end. Matrix translations are interpreted from right to left. The matrix.identity is in reference to the origin of the cameras view. If you have view.lookat(matrix.identity * myMatrix); myMatrix isnt interpreted correctly if you are depending on your object to be at the viewports origin.

Heres a good reference.

http://www.riemers.net/eng/Tutorials/XNA/Csharp/Series2D/Coll_Detection_Matrices.php