I’ve been taking a look at some of the work being done on PTM like texture
mapping. Has anyone used anything like this in an actual game? It seems
like it would be a rather promising technique.
Anyone know anything about it or where to find more info about it (except HP’s homepage)?
I believe that (today) PTM must be perfromed entierly in software, meaning that it is not well suited for games. I too think that it’s an interesting technique, which could probably be used to produce all kinds of interesting effects.
actually ptm is quite easy in hardware, just eats up 2 or 4 textures (or 8? ), so we need to redesign the whole shader… but its working yet… nvidia demo is out (download cgshader thingthong… there you’ll see it)
anyways… polynomial texturemapping can be done in todays hw. i’m pretty sure about this… i’ll look for some papers and think about some implementation…
but the most difficult part of the polynomials is not the rendering actually but the generation… bumpmaps and diffuse textures are easy, but for polynomials you should model with materials and all the actualy geometry and then render from all sides… ====> need a max-plugin
PTMs can absolutely be done on today’s hardware. The reconstruction takes only a few multitexture operations. The real trick to adoption of PTMs is the art path, which is non-existent in commonly-available tools.
Originally posted by JasonM [ATI]:
[b]PTMs can absolutely be done on today’s hardware. The reconstruction takes only a few multitexture operations. The real trick to adoption of PTMs is the art path, which is non-existent in commonly-available tools.
-Jason[/b]
I guess this will be added to my list of cool thing to do then, once I get my hands on a GF4
You don’t need a GF4 to do PTM. At least as far as I recall PTM:
Specify the coefficients of a polynomial per-texel; specify the “x” to evaluate the polynomial with when you render (or per-texel from another polynomial, I suppose).
If you’re OK with a grayscale PTM, you can do a quadratic polynomial in a single DOT3 texture operation. Set up your color r/g/b as 1, x and x*x. Then the r/g/b of the texel are the coefficients c, b and a in the polynomial ax2 + bx + c.
To anyone who bumped to this thread from google just like I do. PTM’s are now mostly used exclusively in digital conservation of cultural material. HP labs seem to have ceased its development. It’s page is inaccessible now. However there are some museums and other cultural material providers that still distribute ptms. A very basic rendering software for RGB PTMs is provided in github: D-K-E/ptm-viewer using OpenGL core profile version 330 with a PySide2 interface. Please refer to there for further discussion.