CopyMemory with modulo

Kaeru Gaman · Post by **Kaeru Gaman** » Mon Apr 16, 2007 1:32 pm

dell_jockey wrote:alors, I still don't really get it. Where would this be useful, can somebody please explain?

same here.

what would you need such a function for....?

it's for small data copying but several copy to do :p

I don't see the connection between this sentence and the functionality requested.....

freddix · Post by **freddix** » Mon Apr 16, 2007 2:37 pm

Imagine I want to make an Amiga Emuator on PC ...
If I want to simulate the Amiga Blitter, I need something like this.
(I'm not making an Amiga emulator, that was just to give a sample of use)

Kaeru Gaman · Post by **Kaeru Gaman** » Mon Apr 16, 2007 3:50 pm

since I dunno the AmigaBlitter, I still don't understand the purpose.

but it's ok, programmers sometimes ask for things, others don't understand instantly...
so, you have a solution now, perhaps we see some illustrative example some day...

freddix · Post by **freddix** » Tue Apr 17, 2007 1:29 pm

Here is what memory copy is with modulo :

For example, imagine that the left grid is the screen represented by bytes
and the right is an image grabbed from screen (8 bits display)

You copy 3 lines with 5 bytes and a modulo value of 6 ( =6 bytes skipped )
Giving an image of 5x3 pixels.

freddix · Post by **freddix** » Wed May 02, 2007 10:58 pm

Hi,

@wilbert:
Do you think it's possible to modify your memorycopy function to handle 1 bytes/4 to set transparency and overlap target content ?
In fact, it will copy by 4 bytes minimum (.l) and these bytes contain ARGB values. so, when reading, it read Alpha, R, G, B, Read same for target and calculate final pixel from both pixels. write final one.
Is it possible ?