Quote:
Originally Posted by robinsonb5
A multi-pass blitter algorithm can modify the data in-place much faster than the CPU would be able to.
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Cough. No, this depends on the CPU, and the operation. The blitter cannot do magic, it can only operate at the bandwidth of the chip RAM bus, and the CPU can also only access chip RAM at the same speed. However, depending on how many source channels you take, and depending on the blitter nasty flag, the blitter cannot occupy every possible cycle (i.e. every cycle not taken by DMA).
In particular, if you have complex operations like subtractions the blitter cannot perform (without going through multiple iterations at least), the CPU becomes faster.
Thus, while there is an advantage of the blitter for a poor old 68000, this advantage melts away quite quickly with faster CPUs. The blitter can still be of some advantage for faster CPUs if the CPU can do something else while the blitter is operating on the screen, but if manipulating chip mem is the only thing that needs to be done, then a faster CPU will outperform the blitter easily.
Quote:
Originally Posted by robinsonb5
I've used the same techniques to draw shaded bevels on a 16-colour greyscale screen, again much faster than the CPU could do it.
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In this generality, certainly not. As said, a CPU on a turbo board can access chip memory every cycle, and therefore saturate the chip memory bus easily. The blitter will not be able to do so, *except* if you really need all channels, and set the blitter nasty flag.