05-04-2003, 10:37 AM
I'm in the process of writing subs to enable me to have a buffer in screen buffer in Screen 13. The only problem is, they have ended up being very, very slow. It takes quite a long time for each of them to run and thus my graphics are fairly slow (although there are no flicker problmes 
). Anyway, I was just wondering what suggestions, if any, you guys had as to what to do to increase the speed of my routines. One thought I had, don't know if its worth doing, or even possible (due to the offset limit size) was to only define my segment once and then just use offsets to reference my memory locations. As you can probably see, the routine I use below (te equivelant of put) is quite calculation intensive and redifnes the segment 2 times per cycle. BTW, page() is the screen buffer.
). Anyway, I was just wondering what suggestions, if any, you guys had as to what to do to increase the speed of my routines. One thought I had, don't know if its worth doing, or even possible (due to the offset limit size) was to only define my segment once and then just use offsets to reference my memory locations. As you can probably see, the routine I use below (te equivelant of put) is quite calculation intensive and redifnes the segment 2 times per cycle. BTW, page() is the screen buffer.Code:
SUB fastput (x%, y%, img%()) 'has automasking feature
wimg& = img%(0) / 8 'determines width of the image to be put
himg& = img%(1) 'determines height of the image
wpage& = page(0) / 8 'determines width of the page to be written to
simg& = VARPTR(img%(2)) 'finds the start of the img to be displayed
spage& = VARPTR(page(2)) 'finds the start of the actual graphics data
FOR ycnt& = 0 TO himg& - 1 'loops through the images rows
FOR xcnt& = 0 TO wimg& - 1 'loops through the columns of a row in the image
oimg& = wimg& * ycnt& + xcnt& + simg& 'finds the pixel in the images offset
'DEF SEG = VARSEG(img%(0)) + INT(oimg& / 16) 'sets the segment of the pixel being pulled from the image
DEF SEG = VARSEG(img%(0))
'pixeltocopy% = PEEK(oimg& MOD 16) 'gets the value at the pixel
pixeltocopy% = PEEK(oimg&)
'PSET (xcnt& + 20, ycnt& + 20), pixeltocopy%
IF pixeltocopy% THEN
opage& = wpage& * (ycnt& + y%) + xcnt& + x% + spage& 'finds offset in screen buffer
DEF SEG = VARSEG(page%(0)) + INT(opage& / 16) 'sets the segment of the pixel being placed on the page
POKE opage& MOD 16, pixeltocopy% 'places the pixel in the page buffer
END IF
NEXT xcnt&
NEXT ycnt&
DEF SEG 'returns segment to basic's default
END SUB