I just got a problem with drawing two 3D cubes standing in line. In my code, I made a cube class, and in the game1 class, I built two cubes, A on the right side, B on the left side. I also setup an FPS camera in the 3D world. The problem is if I draw cube B first(Blue), and move the camera to the left side to cube B, A(Red) is still standing in front of B, which is apparently wrong.

I guess some pics can make much sense. Then, I move the camera to the other side, the situation is like: This is wrong.... From this view, the red cube, A should be behind the blue one, B....

Could somebody give me help please?

This is the draw in the Cube class

Matrix center = Matrix.CreateTranslation(
new Vector3(-0.5f, -0.5f, -0.5f));
Matrix scale = Matrix.CreateScale(0.5f);
Matrix translate = Matrix.CreateTranslation(location);
effect.World = center * scale * translate;
effect.View = camera.View;
effect.Projection = camera.Projection;

foreach (EffectPass pass in effect.CurrentTechnique.Passes)
            {
                pass.Apply();
                device.SetVertexBuffer(cubeBuffer);

                RasterizerState rs = new RasterizerState();
                rs.CullMode = CullMode.None;
                rs.FillMode = FillMode.Solid;
                device.RasterizerState = rs;

                device.DrawPrimitives(
                PrimitiveType.TriangleList,
                0,
                cubeBuffer.VertexCount / 3);
            }

This is the Draw method in game1

A.Draw(camera, effect); B.Draw(camera, effect);

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