Since we do our rendering with VTK (instead of IIL4Mitk), software OpenGL rendering is broken in many cases.

Rendering of "non-power-of-two" (NPOT) textures in supported by some OpenGL extension, which is mainly implemented in some graphics card drivers BUT NOT e.g. in the Microsoft Windows OpenGL driver.

When NPOT images are rendered, the texture plane is extended to the next power of two (by VTK, in order to satisfy the driver's limitation). However, VTK does not extend the texture image, so rendering stretches the NPOT texture onto the power-of-two texture plane. The resulting rendering is painly wrong and potentially dangerous, because any kind of measurements on such a rendering will be faulty.