248 |
are different, and it happens to be that \emph{in screen space}, anisotropic filtering |
are different, and it happens to be that \emph{in screen space}, anisotropic filtering |
249 |
of an anisotropic texture is always better than the isotropic filtering of |
of an anisotropic texture is always better than the isotropic filtering of |
250 |
an isotropic texture. This is shown in detail in Fig.~\ref{figstretchsquishwhyworks}. |
an isotropic texture. This is shown in detail in Fig.~\ref{figstretchsquishwhyworks}. |
251 |
The trilinear filter footpring size depends strongly on subpixel position and |
The trilinear filter footprint size depends strongly on subpixel position and |
252 |
can be quite large compared to the actual pixel, causing blurring. |
can be quite large compared to the actual pixel, causing blurring. |
253 |
When using the anisotropic filter, the footprint remains significantly smaller |
When using the anisotropic filter, the footprint remains significantly smaller |
254 |
in one direction regardless of subpixel shifting --- in the other direction, |
in one direction regardless of subpixel shifting --- in the other direction, |
255 |
it is similar. |
it is similar. |
256 |
|
|
257 |
- analogous to supersampling |
- too large footprint --> blurry |
258 |
|
|
259 |
|
- too small footprint --> aliasing |
260 |
|
|
261 |
|
- aliasing worse than blurring |
262 |
|
--> footprint made too large rather than too small (mipmap levels) |
263 |
|
|
264 |
|
- when texels are narrower in one direction, the granularity of the |
265 |
|
pixel footprint will be smaller in that direction |
266 |
|
|
267 |
|
- thus, the footprint can better match the pixel in that direction |
268 |
|
|
269 |
|
- however, a larger number of narrow texels is needed to fill the |
270 |
|
area of the pixel |
271 |
|
|
272 |
|
- analogous to supersampling |
273 |
|
|
274 |
- downsides: |
- downsides: |
275 |
|
|
292 |
% Hard to assess quality if zoomed too much (if the pixels are clearly |
% Hard to assess quality if zoomed too much (if the pixels are clearly |
293 |
% visible, the grid structure will obscure the actual image). |
% visible, the grid structure will obscure the actual image). |
294 |
% Is this fig referred to? |
% Is this fig referred to? |
|
|
|
295 |
} |
} |
296 |
\end{figure*} |
\end{figure*} |
297 |
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|