Category : Files from Magazines
Archive : DDJ8_91.ZIP
Filename : GRAPH_PR.ASC
Output of file : GRAPH_PR.ASC contained in archive : DDJ8_91.ZIP
by Michael Abrash
[LISTING ONE]
/* Program to demonstrate mode X (320x240, 256 colors) patterned
rectangle fills by filling the screen with adjacent 80x60
rectangles in a variety of patterns. Tested with Borland C++
2.0 in C compilation mode and the small model */
#include
#include
void Set320x240Mode(void);
void FillPatternX(int, int, int, int, unsigned int, char*);
/* 16 4x4 patterns */
static char Patt0[]={10,0,10,0,0,10,0,10,10,0,10,0,0,10,0,10};
static char Patt1[]={9,0,0,0,0,9,0,0,0,0,9,0,0,0,0,9};
static char Patt2[]={5,0,0,0,0,0,5,0,5,0,0,0,0,0,5,0};
static char Patt3[]={14,0,0,14,0,14,14,0,0,14,14,0,14,0,0,14};
static char Patt4[]={15,15,15,1,15,15,1,1,15,1,1,1,1,1,1,1};
static char Patt5[]={12,12,12,12,6,6,6,12,6,6,6,12,6,6,6,12};
static char Patt6[]={80,80,80,80,80,80,80,80,80,80,80,80,80,80,80,15};
static char Patt7[]={78,78,78,78,80,80,80,80,82,82,82,82,84,84,84,84};
static char Patt8[]={78,80,82,84,80,82,84,78,82,84,78,80,84,78,80,82};
static char Patt9[]={78,80,82,84,78,80,82,84,78,80,82,84,78,80,82,84};
static char Patt10[]={0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
static char Patt11[]={0,1,2,3,0,1,2,3,0,1,2,3,0,1,2,3};
static char Patt12[]={14,14,9,9,14,9,9,14,9,9,14,14,9,14,14,9};
static char Patt13[]={15,8,8,8,15,15,15,8,15,15,15,8,15,8,8,8};
static char Patt14[]={3,3,3,3,3,7,7,3,3,7,7,3,3,3,3,3};
static char Patt15[]={0,0,0,0,0,64,0,0,0,0,0,0,0,0,0,89};
/* Table of pointers to the 16 4x4 patterns with which to draw */
static char* PattTable[] = {Patt0,Patt1,Patt2,Patt3,Patt4,Patt5,Patt6,
Patt7,Patt8,Patt9,Patt10,Patt11,Patt12,Patt13,Patt14,Patt15};
void main() {
int i,j;
union REGS regset;
Set320x240Mode();
for (j = 0; j < 4; j++) {
for (i = 0; i < 4; i++) {
FillPatternX(i*80,j*60,i*80+80,j*60+60,0,PattTable[j*4+i]);
}
}
getch();
regset.x.ax = 0x0003; /* switch back to text mode and done */
int86(0x10, ®set, ®set);
}
[LISTING TWO]
; Mode X (320x240, 256 colors) rectangle 4x4 pattern fill routine.
; Upper left corner of pattern is always aligned to a multiple-of-4
; row and column. Works on all VGAs. Uses approach of copying the
; pattern to off-screen display memory, then loading the latches with
; the pattern for each scan line and filling each scan line four
; pixels at a time. Fills up to but not including the column at EndX
; and the row at EndY. No clipping is performed. All ASM code tested
; with TASM 2. C near-callable as:
; void FillPatternedX(int StartX, int StartY, int EndX, int EndY,
; unsigned int PageBase, char* Pattern);
SC_INDEX equ 03c4h ;Sequence Controller Index register port
MAP_MASK equ 02h ;index in SC of Map Mask register
GC_INDEX equ 03ceh ;Graphics Controller Index register port
BIT_MASK equ 08h ;index in GC of Bit Mask register
PATTERN_BUFFER equ 0fffch ;offset in screen memory of the buffer used
; to store each pattern during drawing
SCREEN_SEG equ 0a000h ;segment of display memory in mode X
SCREEN_WIDTH equ 80 ;width of screen in addresses from one scan
; line to the next
parms struc
dw 2 dup (?) ;pushed BP and return address
StartX dw ? ;X coordinate of upper left corner of rect
StartY dw ? ;Y coordinate of upper left corner of rect
EndX dw ? ;X coordinate of lower right corner of rect
; (the row at EndX is not filled)
EndY dw ? ;Y coordinate of lower right corner of rect
; (the column at EndY is not filled)
PageBase dw ? ;base offset in display memory of page in
; which to fill rectangle
Pattern dw ? ;4x4 pattern with which to fill rectangle
parms ends
NextScanOffset equ -2 ;local storage for distance from end of one
; scan line to start of next
RectAddrWidth equ -4 ;local storage for address width of rectangle
Height equ -6 ;local storage for height of rectangle
STACK_FRAME_SIZE equ 6
.model small
.data
; Plane masks for clipping left and right edges of rectangle.
LeftClipPlaneMask db 00fh,00eh,00ch,008h
RightClipPlaneMask db 00fh,001h,003h,007h
.code
public _FillPatternX
_FillPatternX proc near
push bp ;preserve caller's stack frame
mov bp,sp ;point to local stack frame
sub sp,STACK_FRAME_SIZE ;allocate space for local vars
push si ;preserve caller's register variables
push di
cld
mov ax,SCREEN_SEG ;point ES to display memory
mov es,ax
;copy pattern to display memory buffer
mov si,[bp+Pattern] ;point to pattern to fill with
mov di,PATTERN_BUFFER ;point ES:DI to pattern buffer
mov dx,SC_INDEX ;point Sequence Controller Index to
mov al,MAP_MASK ; Map Mask
out dx,al
inc dx ;point to SC Data register
mov cx,4 ;4 pixel quadruplets in pattern
DownloadPatternLoop:
mov al,1 ;
out dx,al ;select plane 0 for writes
movsb ;copy over next plane 0 pattern pixel
dec di ;stay at same address for next plane
mov al,2 ;
out dx,al ;select plane 1 for writes
movsb ;copy over next plane 1 pattern pixel
dec di ;stay at same address for next plane
mov al,4 ;
out dx,al ;select plane 2 for writes
movsb ;copy over next plane 2 pattern pixel
dec di ;stay at same address for next plane
mov al,8 ;
out dx,al ;select plane 3 for writes
movsb ;copy over next plane 3 pattern pixel
; and advance address
loop DownloadPatternLoop
mov dx,GC_INDEX ;set the bit mask to select all bits
mov ax,00000h+BIT_MASK ; from the latches and none from
out dx,ax ; the CPU, so that we can write the
; latch contents directly to memory
mov ax,[bp+StartY] ;top rectangle scan line
mov si,ax
and si,011b ;top rect scan line modulo 4
add si,PATTERN_BUFFER ;point to pattern scan line that
; maps to top line of rect to draw
mov dx,SCREEN_WIDTH
mul dx ;offset in page of top rectangle scan line
mov di,[bp+StartX]
mov bx,di
shr di,1 ;X/4 = offset of first rectangle pixel in scan
shr di,1 ; line
add di,ax ;offset of first rectangle pixel in page
add di,[bp+PageBase] ;offset of first rectangle pixel in
; display memory
and bx,0003h ;look up left edge plane mask
mov ah,LeftClipPlaneMask[bx] ; to clip
mov bx,[bp+EndX]
and bx,0003h ;look up right edge plane
mov al,RightClipPlaneMask[bx] ; mask to clip
mov bx,ax ;put the masks in BX
mov cx,[bp+EndX] ;calculate # of addresses across rect
mov ax,[bp+StartX]
cmp cx,ax
jle FillDone ;skip if 0 or negative width
dec cx
and ax,not 011b
sub cx,ax
shr cx,1
shr cx,1 ;# of addresses across rectangle to fill - 1
jnz MasksSet ;there's more than one pixel to draw
and bh,bl ;there's only one pixel, so combine the left
; and right edge clip masks
MasksSet:
mov ax,[bp+EndY]
sub ax,[bp+StartY] ;AX = height of rectangle
jle FillDone ;skip if 0 or negative height
mov [bp+Height],ax
mov ax,SCREEN_WIDTH
sub ax,cx ;distance from end of one scan line to start
dec ax ; of next
mov [bp+NextScanOffset],ax
mov [bp+RectAddrWidth],cx ;remember width in addresses - 1
mov dx,SC_INDEX+1 ;point to Sequence Controller Data reg
; (SC Index still points to Map Mask)
FillRowsLoop:
mov cx,[bp+RectAddrWidth] ;width across - 1
mov al,es:[si] ;read display memory to latch this scan
; line's pattern
inc si ;point to the next pattern scan line, wrapping
jnz short NoWrap ; back to the start of the pattern if
sub si,4 ; we've run off the end
NoWrap:
mov al,bh ;put left-edge clip mask in AL
out dx,al ;set the left-edge plane (clip) mask
stosb ;draw the left edge (pixels come from latches;
; value written by CPU doesn't matter)
dec cx ;count off left edge address
js FillLoopBottom ;that's the only address
jz DoRightEdge ;there are only two addresses
mov al,00fh ;middle addresses are drawn 4 pixels at a pop
out dx,al ;set the middle pixel mask to no clip
rep stosb ;draw the middle addresses four pixels apiece
; (from latches; value written doesn't matter)
DoRightEdge:
mov al,bl ;put right-edge clip mask in AL
out dx,al ;set the right-edge plane (clip) mask
stosb ;draw the right edge (from latches; value
; written doesn't matter)
FillLoopBottom:
add di,[bp+NextScanOffset] ;point to the start of the next scan
; line of the rectangle
dec word ptr [bp+Height] ;count down scan lines
jnz FillRowsLoop
FillDone:
mov dx,GC_INDEX+1 ;restore the bit mask to its default,
mov al,0ffh ; which selects all bits from the CPU
out dx,al ; and none from the latches (the GC
; Index still points to Bit Mask)
pop di ;restore caller's register variables
pop si
mov sp,bp ;discard storage for local variables
pop bp ;restore caller's stack frame
ret
_FillPatternX endp
end
[LISTING THREE]
; Mode X (320x240, 256 colors) display memory to display memory copy
; routine. Left edge of source rectangle modulo 4 must equal left edge
; of destination rectangle modulo 4. Works on all VGAs. Uses approach
; of reading 4 pixels at a time from the source into the latches, then
; writing the latches to the destination. Copies up to but not
; including the column at SourceEndX and the row at SourceEndY. No
; clipping is performed. Results are not guaranteed if the source and
; destination overlap. C near-callable as:
; void CopyScreenToScreenX(int SourceStartX, int SourceStartY,
; int SourceEndX, int SourceEndY, int DestStartX,
; int DestStartY, unsigned int SourcePageBase,
; unsigned int DestPageBase, int SourceBitmapWidth,
; int DestBitmapWidth);
SC_INDEX equ 03c4h ;Sequence Controller Index register port
MAP_MASK equ 02h ;index in SC of Map Mask register
GC_INDEX equ 03ceh ;Graphics Controller Index register port
BIT_MASK equ 08h ;index in GC of Bit Mask register
SCREEN_SEG equ 0a000h ;segment of display memory in mode X
parms struc
dw 2 dup (?) ;pushed BP and return address
SourceStartX dw ? ;X coordinate of upper left corner of source
SourceStartY dw ? ;Y coordinate of upper left corner of source
SourceEndX dw ? ;X coordinate of lower right corner of source
; (the row at SourceEndX is not copied)
SourceEndY dw ? ;Y coordinate of lower right corner of source
; (the column at SourceEndY is not copied)
DestStartX dw ? ;X coordinate of upper left corner of dest
DestStartY dw ? ;Y coordinate of upper left corner of dest
SourcePageBase dw ? ;base offset in display memory of page in
; which source resides
DestPageBase dw ? ;base offset in display memory of page in
; which dest resides
SourceBitmapWidth dw ? ;# of pixels across source bitmap
; (must be a multiple of 4)
DestBitmapWidth dw ? ;# of pixels across dest bitmap
; (must be a multiple of 4)
parms ends
SourceNextScanOffset equ -2 ;local storage for distance from end of
; one source scan line to start of next
DestNextScanOffset equ -4 ;local storage for distance from end of
; one dest scan line to start of next
RectAddrWidth equ -6 ;local storage for address width of rectangle
Height equ -8 ;local storage for height of rectangle
STACK_FRAME_SIZE equ 8
.model small
.data
; Plane masks for clipping left and right edges of rectangle.
LeftClipPlaneMask db 00fh,00eh,00ch,008h
RightClipPlaneMask db 00fh,001h,003h,007h
.code
public _CopyScreenToScreenX
_CopyScreenToScreenX proc near
push bp ;preserve caller's stack frame
mov bp,sp ;point to local stack frame
sub sp,STACK_FRAME_SIZE ;allocate space for local vars
push si ;preserve caller's register variables
push di
push ds
cld
mov dx,GC_INDEX ;set the bit mask to select all bits
mov ax,00000h+BIT_MASK ; from the latches and none from
out dx,ax ; the CPU, so that we can write the
; latch contents directly to memory
mov ax,SCREEN_SEG ;point ES to display memory
mov es,ax
mov ax,[bp+DestBitmapWidth]
shr ax,1 ;convert to width in addresses
shr ax,1
mul [bp+DestStartY] ;top dest rect scan line
mov di,[bp+DestStartX]
shr di,1 ;X/4 = offset of first dest rect pixel in
shr di,1 ; scan line
add di,ax ;offset of first dest rect pixel in page
add di,[bp+DestPageBase] ;offset of first dest rect pixel
; in display memory
mov ax,[bp+SourceBitmapWidth]
shr ax,1 ;convert to width in addresses
shr ax,1
mul [bp+SourceStartY] ;top source rect scan line
mov si,[bp+SourceStartX]
mov bx,si
shr si,1 ;X/4 = offset of first source rect pixel in
shr si,1 ; scan line
add si,ax ;offset of first source rect pixel in page
add si,[bp+SourcePageBase] ;offset of first source rect
; pixel in display memory
and bx,0003h ;look up left edge plane mask
mov ah,LeftClipPlaneMask[bx] ; to clip
mov bx,[bp+SourceEndX]
and bx,0003h ;look up right edge plane
mov al,RightClipPlaneMask[bx] ; mask to clip
mov bx,ax ;put the masks in BX
mov cx,[bp+SourceEndX] ;calculate # of addresses across
mov ax,[bp+SourceStartX] ; rect
cmp cx,ax
jle CopyDone ;skip if 0 or negative width
dec cx
and ax,not 011b
sub cx,ax
shr cx,1
shr cx,1 ;# of addresses across rectangle to copy - 1
jnz MasksSet ;there's more than one address to draw
and bh,bl ;there's only one address, so combine the left
; and right edge clip masks
MasksSet:
mov ax,[bp+SourceEndY]
sub ax,[bp+SourceStartY] ;AX = height of rectangle
jle CopyDone ;skip if 0 or negative height
mov [bp+Height],ax
mov ax,[bp+DestBitmapWidth]
shr ax,1 ;convert to width in addresses
shr ax,1
sub ax,cx ;distance from end of one dest scan line to
dec ax ; start of next
mov [bp+DestNextScanOffset],ax
mov ax,[bp+SourceBitmapWidth]
shr ax,1 ;convert to width in addresses
shr ax,1
sub ax,cx ;distance from end of one source scan line to
dec ax ; start of next
mov [bp+SourceNextScanOffset],ax
mov [bp+RectAddrWidth],cx ;remember width in addresses - 1
mov dx,SC_INDEX+1 ;point to Sequence Controller Data reg
; (SC Index still points to Map Mask)
mov ax,es ;DS=ES=screen segment for MOVS
mov ds,ax
CopyRowsLoop:
mov cx,[bp+RectAddrWidth] ;width across - 1
mov al,bh ;put left-edge clip mask in AL
out dx,al ;set the left-edge plane (clip) mask
movsb ;copy the left edge (pixels go through
; latches)
dec cx ;count off left edge address
js CopyLoopBottom ;that's the only address
jz DoRightEdge ;there are only two addresses
mov al,00fh ;middle addresses are drawn 4 pixels at a pop
out dx,al ;set the middle pixel mask to no clip
rep movsb ;draw the middle addresses four pixels apiece
; (pixels copied through latches)
DoRightEdge:
mov al,bl ;put right-edge clip mask in AL
out dx,al ;set the right-edge plane (clip) mask
movsb ;draw the right edge (pixels copied through
; latches)
CopyLoopBottom:
add si,[bp+SourceNextScanOffset] ;point to the start of
add di,[bp+DestNextScanOffset] ; next source & dest lines
dec word ptr [bp+Height] ;count down scan lines
jnz CopyRowsLoop
CopyDone:
mov dx,GC_INDEX+1 ;restore the bit mask to its default,
mov al,0ffh ; which selects all bits from the CPU
out dx,al ; and none from the latches (the GC
; Index still points to Bit Mask)
pop ds
pop di ;restore caller's register variables
pop si
mov sp,bp ;discard storage for local variables
pop bp ;restore caller's stack frame
ret
_CopyScreenToScreenX endp
end
[LISTING FOUR]
; Mode X (320x240, 256 colors) system memory to display memory copy
; routine. Uses approach of changing the plane for each pixel copied;
; this is slower than copying all pixels in one plane, then all pixels
; in the next plane, and so on, but it is simpler; besides, images for
; which performance is critical should be stored in off-screen memory
; and copied to the screen via the latches. Copies up to but not
; including the column at SourceEndX and the row at SourceEndY. No
; clipping is performed. C near-callable as:
; void CopySystemToScreenX(int SourceStartX, int SourceStartY,
; int SourceEndX, int SourceEndY, int DestStartX,
; int DestStartY, char* SourcePtr, unsigned int DestPageBase,
; int SourceBitmapWidth, int DestBitmapWidth);
SC_INDEX equ 03c4h ;Sequence Controller Index register port
MAP_MASK equ 02h ;index in SC of Map Mask register
SCREEN_SEG equ 0a000h ;segment of display memory in mode X
parms struc
dw 2 dup (?) ;pushed BP and return address
SourceStartX dw ? ;X coordinate of upper left corner of source
SourceStartY dw ? ;Y coordinate of upper left corner of source
SourceEndX dw ? ;X coordinate of lower right corner of source
; (the row at EndX is not copied)
SourceEndY dw ? ;Y coordinate of lower right corner of source
; (the column at EndY is not copied)
DestStartX dw ? ;X coordinate of upper left corner of dest
DestStartY dw ? ;Y coordinate of upper left corner of dest
SourcePtr dw ? ;pointer in DS to start of bitmap in which
; source resides
DestPageBase dw ? ;base offset in display memory of page in
; which dest resides
SourceBitmapWidth dw ? ;# of pixels across source bitmap
DestBitmapWidth dw ? ;# of pixels across dest bitmap
; (must be a multiple of 4)
parms ends
RectWidth equ -2 ;local storage for width of rectangle
LeftMask equ -4 ;local storage for left rect edge plane mask
STACK_FRAME_SIZE equ 4
.model small
.code
public _CopySystemToScreenX
_CopySystemToScreenX proc near
push bp ;preserve caller's stack frame
mov bp,sp ;point to local stack frame
sub sp,STACK_FRAME_SIZE ;allocate space for local vars
push si ;preserve caller's register variables
push di
cld
mov ax,SCREEN_SEG ;point ES to display memory
mov es,ax
mov ax,[bp+SourceBitmapWidth]
mul [bp+SourceStartY] ;top source rect scan line
add ax,[bp+SourceStartX]
add ax,[bp+SourcePtr] ;offset of first source rect pixel
mov si,ax ; in DS
mov ax,[bp+DestBitmapWidth]
shr ax,1 ;convert to width in addresses
shr ax,1
mov [bp+DestBitmapWidth],ax ;remember address width
mul [bp+DestStartY] ;top dest rect scan line
mov di,[bp+DestStartX]
mov cx,di
shr di,1 ;X/4 = offset of first dest rect pixel in
shr di,1 ; scan line
add di,ax ;offset of first dest rect pixel in page
add di,[bp+DestPageBase] ;offset of first dest rect pixel
; in display memory
and cl,011b ;CL = first dest pixel's plane
mov al,11h ;upper nibble comes into play when plane wraps
; from 3 back to 0
shl al,cl ;set the bit for the first dest pixel's plane
mov [bp+LeftMask],al ; in each nibble to 1
mov cx,[bp+SourceEndX] ;calculate # of pixels across
sub cx,[bp+SourceStartX] ; rect
jle CopyDone ;skip if 0 or negative width
mov [bp+RectWidth],cx
mov bx,[bp+SourceEndY]
sub bx,[bp+SourceStartY] ;BX = height of rectangle
jle CopyDone ;skip if 0 or negative height
mov dx,SC_INDEX ;point to SC Index register
mov al,MAP_MASK
out dx,al ;point SC Index reg to the Map Mask
inc dx ;point DX to SC Data reg
CopyRowsLoop:
mov ax,[bp+LeftMask]
mov cx,[bp+RectWidth]
push si ;remember the start offset in the source
push di ;remember the start offset in the dest
CopyScanLineLoop:
out dx,al ;set the plane for this pixel
movsb ;copy the pixel to the screen
rol al,1 ;set mask for next pixel's plane
cmc ;advance destination address only when
sbb di,0 ; wrapping from plane 3 to plane 0
; (else undo INC DI done by MOVSB)
loop CopyScanLineLoop
pop di ;retrieve the dest start offset
add di,[bp+DestBitmapWidth] ;point to the start of the
; next scan line of the dest
pop si ;retrieve the source start offset
add si,[bp+SourceBitmapWidth] ;point to the start of the
; next scan line of the source
dec bx ;count down scan lines
jnz CopyRowsLoop
CopyDone:
pop di ;restore caller's register variables
pop si
mov sp,bp ;discard storage for local variables
pop bp ;restore caller's stack frame
ret
_CopySystemToScreenX endp
end
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