'===========================================================================
' Subject: FAST SPRITE ROUTINE               Date: Year of 1993           
' Author:  Calvin French/Victor Yiu          Code: ASM, QB, PDS           
' Origin:  FidoNet QUIK_BAS Echo           Packet: GRAPHICS.ABC
'===========================================================================
' Here is the self-extracting script that makes a QuickBasic/PDS callable
' OBJect file containing Sprite manipulation code in assembly.
' More information (source) on next page...
'
'>>> Page 1 of SPRITE.OBJ begins here. TYPE:BINAA TLEN:142
DEFINT A-Z:DIM SHARED K,S,B&,Z&:V1 'Created by PostIt! 7.1
SUB V1:OPEN "O",1,"SPRITE.OBJ",4^6:Z&=142:?STRING$(50,177);
U"&O-%+%xuwnIyjje%3%%)%htij%+uzg#qnhGAg,%/%n%'(4&+_5%%%&.%uzyx%uw
U"ny%j%%%)Uor%%&%%zGZeC%5&>E/K1%o]*9Zk3]4e&p3\ZM5O&#Z%(+Zs-kXDXvc
U"u%/9eC6y[WqXRPB>e&X0hoC.6dd_lu[$df2_.-D,,C1%*AY'%(%C
END SUB
CLOSE:IF S=158AND B&=Z&THEN?" :) Ok!"ELSE?" :( Bad!
SUB U(A$):FOR A=1TO LEN(A$):C=ASC(MID$(A$,A))-37:IF C<0THEN C=91+C*32
IF K<4THEN K=C+243ELSE?#1,CHR$(C+(K MOD 3)*86);:K=K\3:B&=B&+1
S=(S+C)AND 255:NEXT:LOCATE,1:?STRING$(B&*50\Z&,219);:END SUB
'>>> Page 1 of SPRITE.OBJ ends here. Last page. TCHK:158


'Here's the rewritten code that does exactly yours should do.
'I've included a sample program (posted after this message) to demonstate
'its capabilities (and what it should do).  BTW, it is FAST.  (At least
'fast enough on a 286 to be acceptable.)  It is on par with games from
'Apogee (DUKE Nukem, Cosmo's Adventure's...)!

'BTW -- it is twice as fast as PUT (XOR/OR), but half the speed as PUT
'(PSET).

'Performance on 100x100x256 sprites:
'    10MHz 8088:   7 updates per second     <--- pretty acceptable, considering
'   34MHz 80486: 150 updates per second          what it is...

;=================================================================
; SimpleSprite v1.1 (SSPRITE.ASM) A simple sprite routine
; in asm to overlay GET format images.
;
; Calvin French, 1993  Victor Yiu, 2,348 B.C.
; Released into the Public Domain
;
; NOTE: This routine handles sprites of all sizes *****
;
; DECLARE SUB PutSprite (BYVAL x%, BYVAL y%, BYVAL imgseg%, BYVALimgoff%,_
;       BYVAL imgWid%, BYVAL imgHei%)

CODE SEGMENT PARA 'PUBLIC'
    PUBLIC PutSprite
    ASSUME CS:CODE, DS:nothing, ES:nothing, SS:nothing

BytesPerLine    EQU   320       ; ****** CHANGE to other number is needed
                                ; defaults to 320, for 320x200x256 res.
PutSprite PROC FAR
        PUSH BP         
        MOV BP, SP      ;set up stack frame
        PUSH DS
        PUSH SI
        PUSH DI         ; save BASIC's needed registers

        LDS SI, WORD PTR SS:[BP+10] ; very fast segment/offset loading
                                    ; using LES/DS
        MOV AX, 0A000h
        MOV ES, AX          ; set up vid. mem. addr.

        MOV AX, SS:[BP+14]  ; get Y address
        MOV BX, 320         ; *320
        MUL BX
        MOV DI, SS:[BP+16]  ; put X in SI
        ADD DI, AX          ; add rest -- result in SI

        MOV DX, SS:[BP+6]   ; put height in DX
        MOV CX, SS:[BP+8]   ; put width in CX
        MOV BX, CX          ; save it in BX (width)
        MOV BP, DI          ; save screen pointer to BP

        CLD                 ; look into the future

    ; ============== main stuff starts
EVEN
NewPixel:
        LODSB               ; get byte [DS:SI] -> AL
        OR AL, AL           ; set flags
        JZ Skip             ; if zero (lesser common case), then jump
                            ; Jumping eats processor time and is BAD.
        STOSB               ; if not, write byte
        LOOP NewPixel       ; next loop
EVEN
EndOfLine:                  ; fell out of loop (end of line)
        MOV CX, BX          ; reset count for next loop
        ADD BP, BytesPerLine; increment next screen line
        MOV DI, BP          ; place offset into DI
        DEC DX              ; reduce height
        JZ OttaHere         ; finished?  YES!
        JMP SHORT NewPixel  ; nope -- continue...
EVEN
Skip:                       ; goes here to skip pixel
        INC DI              ; skip byte (don't do anything)
        LOOP NewPixel       ; next pix.
        JMP SHORT EndOfLine ; if end of loop, jump to handler

    ; ============== closing procedure
EVEN 
OttaHere:
        POP DI              ; restore registers
        POP SI
        POP DS
        POP BP
        RET 12              ; and remove 12 bytes of passed params.
PutSprite ENDP              ; from stack
    CODE ENDS
END



'Here's the DEMOnstration program I made to show how FAST it is.
'BTW -- the asm., although acceptably fast, used jumps and no-in-line
'code. I don't know another way of doing it...  Good news is .. IT WORKS!

'Here it goes:
' ========================
DEFINT A-Z

DECLARE SUB PutSprite (BYVAL x%, BYVAL y%, BYVAL imgseg%, BYVAL imgoff%, BYVAL imgWid%, BYVAL imgHei%)
DIM ScreenCut%(5102)      '100x100x256
DIM ScreenCut2%(5102)

SCREEN 13

CLS
RANDOMIZE TIMER
FOR Z = 1 TO 50 STEP 3          ' make demo image to paste
    CIRCLE (50, 50), Z, Z + 16, , , 1.1
NEXT

GET (0, 0)-STEP(100, 100), ScreenCut%
LOCATE 15, 1
PRINT "100x100x256 Color Circle"
PRINT "saved into memory."
PRINT : PRINT "Press any key to change backgrounds"
PRINT "and print sprite."
DO: LOOP UNTIL LEN(INKEY$)

CLS
LINE (0, 0)-(319, 100), 5, BF
PutSprite x, 0, VARSEG(ScreenCut(0)), VARPTR(ScreenCut(0)) + 4, 101,101
LOCATE 15, 1
PRINT "WOW! Notice it DIDN'T destory the"
PRINT "background!"
PRINT : PRINT "Press a key to something cool!"
DO: LOOP UNTIL LEN(INKEY$)

CLS : T! = TIMER: x = 0
LOCATE 24, 7
PRINT "thousand pixels per second!";
LOCATE 25, 6
PRINT "updates per second!   WWWOOOOWW!";

DO UNTIL LEN(INKEY$)
    PutSprite RND * 219, RND * 79, VARSEG(ScreenCut(0)),VARPTR(ScreenCut(0)) + 4, 101, 101
    x = x + 1
    Z! = TIMER - T!
    IF Z! >= 1 THEN
        LOCATE 24, 1
        Z = INT(10 * x / Z!)
        PRINT Z;
        LOCATE 25, 1
        PRINT Z \ 10;
    END IF
LOOP