At work, we've been up to creating a technical demonstration that features an architectural walk-through in an hotel lobby.
Our start point has been VRay renderings done with the model, to setup the ambience. We then worked with RTGU pipeline to export from 3dsmax, and reproduce the lighting.
The biggest challenge was reflections, that are present a little bit everywhere. I tried to approximate the glossy reflections using a volumetric texture storing spherical harmonics. We managed to tune something that's close enough, but reflections are tough beasts. Nest time, gotta try something mixing screen-space techniques maybe.
Another problem we faced was storing the HDR lighting in our lightmap system. The memory budget went up pretty quickly, so we could not afford as many details as we'd have liked. To improve to overall looks of lightmaps, especially in high-contrast zones, we're using Point-disk sampling to upsample the textures - it looks far better than bilinear filtering.
Some more information, and a demo download link, are available here.
Of course, and as always, any feedback is welcome !
While there is probably a direct mapping between DirectX and OpenGL texel formats. I took some time to try to find out which solutions exist to load DDS files for OpenGL. Alas, it seems that there's nothing publicly available that is fancy, or complete, or simple. Everyone seems to do the same work over and over again for their own use.
DirectX and OpenGL use different texture orientation conventions. OpenGL is fed with "bottom first" images, while DirectX eats "top first" images. This may lead to problems, and hopefully solutions, described by tfaure - flipping the images, even in their compressed forms. Does this work for BC7 textures ?
Sample code ?
- some code is also available in Humus framework
- simple snippet, neat, but lacks support of DX10 header parsing and DX10+ pixel formats/compressions : http://www.mindcontrol.org/~hplus/graphics/dds-info/
- a whole library, could be stripped down to provide DDS parsing : NVidia texture tools 2
Is there any DDS database or repository available for testing purpose ? It seems that there are texture packs available, but something simple to automate testing would be nice...