Re: SCREEN1 = SYSVAR @ JSROM
Posted: Sun Jan 12, 2020 1:26 pm
Hi,
Completed stipple patterns, now thinking about relative versus absolute address pointers. My code works with relative so far, e.g. this just stores DOT element, x,y - coord, c - colour.
Using this scheme I can always delete last element from the store, thus undoing the last piece of draw, without much complication of the code. However reordering of elements is done easier with absolute addresses, as it is just pointer swapping.
So perhaps I may build up relative offsets only on load and save operations, while keeping absolute pointers internally for easy editing?
Tomas
Completed stipple patterns, now thinking about relative versus absolute address pointers. My code works with relative so far, e.g. this just stores DOT element, x,y - coord, c - colour.
Code: Select all
210 REMark off - relative offsets, gfx - graphics memory store, top - last offset, ptr - address pointer
220 off=ALCHP(255*2): gfx=ALCHP(2*1024): top=0: POKE_W off+top,4
...
2330 DEFine PROCedure StoreD(x, y, c)
2340 LOCal ptr
2350 ptr=PEEK_W(off+top)+gfx
2360 POKE ptr,CODE('d')
2370 POKE ptr+1,x: POKE ptr+2,y
2380 POKE ptr+3,c: POKE ptr+4,-1
2390 POKE_W off+top+2,PEEK_W(off+top)+4: top=top+2
2400 END DEFine StoreD
So perhaps I may build up relative offsets only on load and save operations, while keeping absolute pointers internally for easy editing?
Tomas