Hi all, I’m new here, please bear with me.
I have a question that Clustying and Googling hasnt been able to answer so far, which is this:
If a texture-mapped polygon is drawn edge-on - that is, at right-angles to the viewing direction/orthogonal to the viewplane - so that in theory it is ‘infinitely thin’, how does modern texturing hardware deal with this case ?
ie. Does the polygon disappear (not drawn), or is the polygon drawn (presumably as a thin line) - and if so (if it is drawn), how is the clockwise/anticlockwise ‘sense’ of the polygon used for texturing in this case, ie. is it honoured ?
I ask because I am researching (I have done a lot more graphics reading and thinking than actual programming, bear with me) real-time Volume Rendering using 2D and 3D textures.
Even though some modern hardware is starting to support 3D textures, I am not yet convinced that 2D textures are as bad as they are made out to be.
Specifically I am not convinced that it is necessary to store 3 copies of the texture stack - one for each of the major axes - as I think this requirement is based on the needs of the good folks trying to render giant datasets (mainly for medical imaging it would appear).
If the stack is sufficiently dense (effectively making it a cell decomposition, but exploiting the hardware’s ability to draw textured quads very very fast), then surely it can be rendered from any angle, provided the sorting order and anti/clock-wise texturing sense is worked out prior to drawing, - PROVIDED, that in the case where the texture stack is orthogonal (at right-angles) to the viewing direction, the quads that hit that case are actually drawn, as thin lines, and dont disappear.
Can anyone help with an answer to this, eg. regarding OpenGL standards and/or NVidia or ATI or other chipsets ?
Have I made myself clear or muddy ?
Best Regards
Jon