public void TestMipmapGen()
{
var original = new Texture3D(IO.LoadImage(TestData.Directory + "checkers3d.dds"));
var tex = original.CloneWithoutMipmapsT();
// check first two slices
TestData.TestCheckers3DLevel0(tex.GetPixelColors(0));
// gen mipmaps
tex = tex.GenerateMipmapLevelsT(3);
TestData.TestCheckers3DLevel0(tex.GetPixelColors(0));
TestData.TestCheckers3DLevel1(tex.GetPixelColors(1));
TestData.TestCheckersLevel2(tex.GetPixelColors(2));
}