micke@slaka.sirius.se (Mikael Karlsson) (05/29/90)
Forget about all that mad bomber jazz and listen up!
Does anybody out there in netland have a blit routine that gives me
more control over the blitter than the currently available functions
AND takes care of all the fuss (WaitBlit, OwnBlitter, etc)?
Thanks in advance
/Mikael
--
\_/ Mikael Karlsson, Lovsattersvagen 10, S-585 98 LINKOPING, SWEDEN
V | micke@slaka.sirius.se
| Absolut Software | micke@slaka.UUCP
~~~ | {mcvax,seismo}!sunic!liuida!slaka!mickebevis@EE.ECN.PURDUE.EDU (Jeff Bevis) (05/30/90)
In article <67293.AA67293@slaka.sirius.se>, micke@slaka.sirius.se (Mikael Karlsson) writes: >Does anybody out there in netland have a blit routine that gives me >more control over the blitter than the currently available functions >AND takes care of all the fuss (WaitBlit, OwnBlitter, etc)? > In assembly or C? I just got Sooooo frustrated with BlitMaskBitMapBlahBlahBlah() etc... that I took a dive into the OwnBlitter() {do satanic things} DisownBlitter() realm. It was, indeed, exhilarating to do the naughty stuff I never let myself do before! (Well, to be fair, I call any writing directy to I/O naughty -- even if in an amiable fashion.) Basically, the code does this (it's torn from a mix of C & asm): (include appropriate files here, like hardware/blit.i) movea.l _GfxBase,a6 jsr _LVOOwnBlitter(a6) ; own the blitter jsr _LVOWaitBlit(a6) ; wait before playing lea _custom,a0 ; regs def'd in custom.i move.w #$ffff,bltafwm(a0) ; first word mask move.w #$ffff,bltalwm(a0) ; last word mask move.w #$0fca,bltcon0(a0) ; blit ctrl & minterm move.w #$0000,bltcon1(a0) ; more blit ctrl move.w #0,bltamod(a0) ; mask modulo is 0 move.w #0,bltbmod(a0) ; same for source image move.w #36,bltcmod(a0) ; dest modulo is 40-4 move.w #36,bltdmod(a0) ; same loop: < figure out addresses for this blit > jsr _LVOWaitBlit(a6) ; wait for last blit to end move.l #DESTADDR,bltdpt(a0) ; destination of blit (WR) move.l #DESTADDR,bltcpt(a0) ; ditto, but read (RD) move.l #SOURCEADDR,bltbpt(a0) ; the source image (RD) move.l #MASKADDR,bltapt(a0) ; the image mask (RD) move.w #$0602,bltsize(a0) ; cause blit to start < branch to loop until done blitting all planes > jsr LVODisownBlitter(a6) ; give back what you have ; stolen (Time Bandits) END This is part of a program I'm currently tinkering with -- it has to blit 64 32x24x5 images, using masks, into a 320x200 screen -- really fast. It does. The modulos for the destination are 36 because the source image is 4 bytes wide and the screen is 40 bytes 'wide'. 40-4==36. This is exactly how I blit. No shifts, no fancy stuff, but I can do anything. (I make no claims about the above code except to say that it works for me) ------------------------------------------------------------------------------- "Three is never equal to four, except for very large values of three." ------------------------------------------------------------------------------- Jeff Bevis Purdue Univeristy School of Electrical Engineering bevis@en.ecn.purdue.edu Give me Amiga or nothing at all. -------------------------------------------------------------------------------