| Tool object used for sampling screen tiles according to estimated pixel variance (used in path tracing engine). To improve GPU thread coherency, rendering window is split into pixel blocks or tiles. The important feature of this approach is that it is possible to keep the same number of tiles for any screen resolution (e.g. 256 tiles can be used for both 512 x 512 window and 1920 x 1080 window). So, a smaller number of tiles allows to increase interactivity (FPS), but at the cost of higher per-frame variance ('noise'). On the contrary a larger number of tiles decrease interactivity, but leads to lower per-frame variance. Note that the total time needed to produce final final image is the same for both cases. More...
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