'===========================================================================
' Subject: SET BITPLANES                     Date: 05-15-96 (15:41)       
' Author:  Jon Merkel                        Code: QB, QBasic, PDS        
' Origin:  FidoNet QUIK_BAS Echo           Packet: GRAPHICS.ABC
'===========================================================================
   ' I thought you would like to see (and would not be offended) by
   ' seeing your code changed a bit. The speed increase is fantastic!
   ' Noticed I changed the line command to a routine that sets the
   ' entire screen with random pixels. Change your code too if you
   ' want to compare speed. Compiled the new code takes 13 seconds
   ' to fill the entire screen. Your code took 2:31 seconds.
   ' I wish I could take credit for this but a guy I know who
   ' programs in ASM and PASCAL (Jon Merkel) looked over your
   ' code and came up with this. I am sure you would like to
   ' see it. I think I know you well enough to know you will
   ' not be offended. But rather amazed at the speed increase.

DECLARE SUB vPSET2 (x%, Y%, Culler%)
 DEFINT A-Z
 SCREEN 12: CLS
 Red% = 4: Green% = 2
 FOR Y% = 0 TO 479
 FOR x% = 0 TO 639
   CALL vPSET2(x%, Y%, RND * 15)
 NEXT: NEXT
 BEEP: SLEEP
 SCREEN 0: WIDTH 80
 END

 SUB vPSET2 (x%, Y%, Culler%)
 
 DEF SEG = &HA000
 
 VideoOffset& = (Y% * 80&) + (x% \ 8)
 
 BitMask% = 1
 FOR J% = 1 TO ((x% AND 7) XOR 7): BitMask% = BitMask% * 2: NEXT
 
 OUT &H3CE, 8: OUT &H3CF, BitMask%
 OUT &H3CE, 5: OUT &H3CF, 2
 
 BYTE% = PEEK(VideoOffset&): POKE VideoOffset&, Culler%
 
 OUT &H3CF, 0
 DEF SEG
 
 END SUB