Subject: Re: [stella] horizontal positioning From: gentlben@xxxxxxxxxxxx Date: Sun, 30 May 1999 09:52:23 -0700 |
> You have to position the object by hitting RESPxx and then you apply the > fine movement in the HMxx register by accessing HMOVE at the beginning > of the next scanline. When you store the value to the HMxx registers > doesn't matter much, because HMOVE will shift all five objects at > the same time according to the values in the five HMxx registers. okay, now do i have to use HMOVE for every scan line, or can i just activate it once per frame? > The thing about objects not showing up in scanlines where RESxx for that > object is accessed is a bit more complicated, but as long as you are > still learning the basics, it is OK to assume, that the object will > start displaying in the following scanline. id rather not assume, but i guess i should just play with it a bit > BTW objects don't get positioned at the pixel that corresponds > with the processor cycle when the access to RESxx happens. > The missiles and the ball have a 4 pixel offset to the right, > normal players have a 5 pixel offset and double/quadruple > players seem to have a 6 pixel offset. hmmmm...this is getting complicated...so balls and missiles display four pixels to the right of the cycle where the reset occurs, while players display five/six pixels to the right of it? <sigh> that sorta gives programmers a headache, doesnt it? :) dee -- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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