I am currently creating a basic volume renderer by slicing through a vector space and creating a texture that corrisponds to a function at that location. This is all working well, however, when drawing the polgon and rendering the texture to it I find that the texture is visible on the front but not the back. I have tried creating forward and back facing one and mapping to both but this also does not seem to work.
Are there any simple ways to achieve this? (In a similar way to allowing both sides of a polygon to be visible)
Also, How does OpenGL determin the side of a polygon to render its contents?
Thanks in advance.