Introduction Description Publications Exhibitions Applications FAQ

Texturing subsystem

NOTE: This page is under construction

The first release of SANTI used the clipmapping texturing system available in IRIS Performer. It run on the SGI Infinite Reality architecture.

Hardware Independent Clipmapping

Some years later, about 2001, we changed to PC platform under Windows/Linux OS and we have to design and implement our own texturing engine. It is based on the clipmapping philosophy, but adapted to the commodity graphics cards available on PC in the early 2000's. This technique has been improved and refined since then. It is well described in some papers, available in the publications section.

The following graphs show some benchmarks of the texturing system. They have been done in a regular PC with an NVIDIA GeForce 7950 GT 512 MB AGP 8x. Even the bus is half the bandwidth of current cards (PCIe 16x), the graphs show that the update is quite acceptable.

Tile size512
Subtile size128
Update time1 ms
Virtual texture512k * 512k texels
Resolution0.5 m/texel
Stack levels19
Filteringtrilinear (4 LODs) + anisotropic (max degree 4)
Texel formatRGB888 (24 bits)

Stack completeness and Speed
Graph 1. Percent of completeness of the TRAM cache (clipmap stack) with an increasing flight speed along 8500 frames (clip size = 1024).

Completeness vs. speed
Graph 2. Stack completeness vs. speed (clip size = 1024).

Stack completeness and Speed
Graph 3. Percent of completeness of the TRAM cache (clipmap stack) with an increasing flight speed along 13000 frames (clip size = 2048).

Completeness vs. speed
Graph 4. Stack completeness vs. speed (clip size = 2048).

Stack completeness and Speed
Graph 5. Percent of completeness of the TRAM cache (clipmap stack) with an increasing flight speed along 6500 frames (clip size = 2048, high speed test).

Completeness vs. speed
Graph 6. Stack completeness vs. speed (clip size = 2048, high speed test).

Dynamic Virtual Textures (GeoTextures)

In year 2008 we released the new generation of our texturing system. It is intended to be used on new GPU generations, supporting shader model 4.0, and offers some new features over the previous technique that is still used for older machines.

The main features of the new technique is the support of dynamic information updated in real time and its versatility used inside custom shaders.

This video shows an example of use of the texturing engine with the NASA Blue Marble data set, updating an 8 gigapixels (128k*64k) RGB image (24 GBytes) updating once per second with a frame update time slot of 3 ms in an NVIDIA GeForce 8800 Ultra.

The player will show in this paragraph

For more detailed technical information about the texturing engine, see the paper presented at WSCG 2009.


Valid HTML 4.01 Transitional Valid CSS!

Last modified: February 18 2009.