GeForce FX Go5700 Image Quality - Anistropic Filtering
Besides the NVIDIA GPU not doing 16x anistropic filtering, there are other filtering issues to examine.No Anistropic Filtering
FilterTest - Click the image for the full size .png version (~1MB)
Serious Sam 2 - Click the image for the full size .png version (~660KB)
The base images shows NVIDIA's now famous 'brilinear' texture filtering. The broader segments of colour show that bilinear is being done instead of trilinear, but full trilinear is performed at the edges of mip transitions. This gives rise to its hard to spot nature. You see texture aliasing most at mip transitions and since the NVIDIA hardware is doing a full trilinear filter at those points, you can be forgiven for missing it sometimes. However it does persist, there's no escaping it.
2x Anistropic Filtering
FilterTest - Click the image for the full size .png version (~1MB)
Serious Sam 2 - Click the image for the full size .png version (~660KB)
Brilinear + 2x aniso action, the NVIDIA GPU performing the aniso filter well, but its quality masked by the optimised added texture filtering.
4x Anistropic Filtering
FilterTest - Click the image for the full size .png version (~1MB)
Serious Sam 2 - Click the image for the full size .png version (~660KB)
A lot less angle dependancy than the ATI GPU in the 4x mode.
8x Anistropic Filtering
FilterTest - Click the image for the full size .png version (~1MB)
Serious Sam 2 - Click the image for the full size .png version (~660KB)
The odd looking filtering 'map' for the first texture stage in FilterTest shows up in the Serious Sam shot, where you can see the curvature of the mip level transition bow out towards the viewer, rather than curve away.
A full trilinear filter is desirable for maximum image quality, but the option to turn off the optimisation isn't present in the driver on NV3x GPUs, at the time of writing.
