toml@xrxns.UUCP (Tom Love) (05/29/87)
hello - with the intention of doing some games-type programming i began looking through the meager ST documentation which is available. in particular, i referred to the Mark Williams C v2.0 manual (already discussed and recommended in this forum) and the Abacus "ST Internals" book (also discussed and generally disparaged). both sources are very, very lean on info describing use of the LineA routines. i am particularly interested in the pseudo-sprites and bitblt. does anyone have pointers to more documentation of any quality on this stuff? i don't have the devpac - how well does it cover linea? any and all pointers to docs or PD source code GREATLY appreciated. on a slightly different topic - how are you hackers out there implementing animation? using linea, or other rom/bios routines, or rolling your own? how reasonable is it to attempt to manage multiple display buffers as an assist to animation? (might as well make use of the ram and the relocatable display base, as long as the result is reasonably fast and leaves time inbetween to update the other buffers). or does this result in flicker or other undesirable side effects? i am mostly interested in moving little goobers around on the screen, sort of pacman style, as opposed to (for example) moving a big object which occupies a majority of the screen, though the techniques involved in that sort of animation might also be interesting. hopefully this set of questions will not be received as naive, and will spark some genuinely interesting technical discussions (as opposed to the relentless atari bashing, amiga bashing, and enless queries for the latest version of uniterm! :-) :-) :-) please reply to me and/or the net. thanks. tom love xerox edds leesburg, va 22075 703-729-8000 uucp: seismo!rochester!rocksanne!xrxns!toml xns: toml:lsbg-egp/cad:xerox
holloway@drivax.UUCP (Bruce Holloway) (06/01/87)
In article <156@xrxns.UUCP> toml@xrxns.UUCP (Tom Love) writes: >on a slightly different topic - how are you hackers out there implementing >animation? using linea, or other rom/bios routines, or rolling your own? >how reasonable is it to attempt to manage multiple display buffers as an >assist to animation? (might as well make use of the ram and the relocatable >display base, as long as the result is reasonably fast and leaves time >inbetween to update the other buffers). or does this result in flicker or >other undesirable side effects? When I do animation (check out "Money", 2/87 ST-Log), I use multiple buffers, drawn with the VDI routines (or read in from disk), and flip them. There's no flicker - the screen base isn't changed until vertical blank. Very smooth animation. I've never used the Line A blit routines 'cause I have no documen- tation on them. But as I understand it, they are only a fast interface into the VDI routines, so they don't give you anything more that using the VDI routines would. On my animation with GEM on the IBM/PC-AT, since you can't change the base of video memory, I instead write over the part of the background that the image has moved past with a filled rectangle routine (usually with a user defined fill pattern), and then draw the new image, very fast. Not much flicker if you do it this way... +-----+...+ |%%%%%| : A = Old position |% %| : B = New position |% B %| A : |% %| : Write over (A - (A intersect B)) with the background |%%%%%| : pattern +-----+...+ Write the sprite at B - Bruce -- Bruce Holloway - Relapsed Newsaholic {ihnp4,seismo,sun}!amdahl!drivax!holloway "Everything should be made as complex as possible - esp. if you're paid hourly." What Irony? 75! - "The Personal Diaries of Albert Einstein" > if they allow you four lines for .signature, the least you can do is use it! <