public void UnprojectingCenterOfViewportWithIdentityViewShouldGenerateAVectorAtCenter()
{
var viewport = new Viewport { Width = 640, Height = 480 };
var aspect = (float) viewport.Height/(float) viewport.Width;
var projection = Matrix.CreatePerspectiveFieldOfView(40f, aspect, 1, 4000f);
var view = Matrix.Identity;
var world = Matrix.Identity;
var position = new Vector((float)viewport.Width/2, (float)viewport.Height/2,0);
var result = viewport.Unproject(position, projection, view, world);
Assert.That(result,Is.EqualTo(new Vector(0,0,-1)));
}
public void UnprojectingCenterOfViewportWithViewRotated90DegreesAroundYAxisShouldGenerateAVectorRotated90DegreesInOpositeDirection()
{
var viewport = new Viewport { Width = 640, Height = 480 };
var aspect = (float)viewport.Height / (float)viewport.Width;
var projection = Matrix.CreatePerspectiveFieldOfView(40f, aspect, 1, 4000f);
var view = Matrix.CreateRotationY(90);
var world = Matrix.Identity;
var position = new Vector((float)viewport.Width / 2, (float)viewport.Height / 2, 0);
var result = viewport.Unproject(position, projection, view, world);
var negativeView = Matrix.CreateRotationY(-90);
var expected = new Vector(0, 0, -1);
var rotatedExpected = expected*negativeView;
Assert.That(result, Is.EqualTo(rotatedExpected));
}