Gury Posted April 8, 2010 Share Posted April 8, 2010 (edited) I present you super fast routine for drawing circles in graphics mode 8 and 8 + 16. Moj Mikro magazine article listings are available as zipped file in download section. It contains ATR disk image file with Atari DOS system for using with disk based, real Atari machine or any Atari 8-bit emulator. To load Atari BASIC programs properly, Atari must be powered with Atari BASIC enabled, or you can try them with any compatible BASIC. You can try, use and modify the programs and routines for whatever purpose you want. Super Fast Circle Routine Magazine: Moj Mikro, 1989/3 Author : Zlatko Bleha Page : 27 - 31 Article link Atari BASIC listing on disk (tokenized): M8903284.BAS Atari BASIC listing (listed): M8903284.LST Assembly language listing: CIRCLE.LST This routine uses very fast algorithm for drawing circles. It works in graphics mode 8. To see it in action, try the following demonstration program, which includes circle routine in DATA tables for using it from Atari BASIC. Also included is assembly language source code for anybody to examine inner workings of the algorithm. It is written in ATMAS 2. Description Algorithm is based on one from Croatian computer magazine Racunari (number 31). There is a little faster way of doing this, but data must be provided in tables for sine and cosine. But this alternative takes more RAM. The routine consists of two parts: main program for calculating X and Y coordinates and second part with PLOT routine for drawing (or erasing) pixels on X and Y coordinates. Calculation of coordinates is done for one eighth of the circle. Other seven parts are simply mirrored from original mentioned pattern. We take advantage of this fact, because circle is simetricly shaped. The routine uses Page Zero locations for variables for even faster execution. There are 17 of them. Usage of the routine A=USR(30000,POK,X,Y,R) 30000 - Starting address of the calling routine POK - 1 (draw the circle), 0 (erase the circle) X - X coordinate of the circle Y - Y coordinate of the circle R - Radius of the circle The routine is not relocatable. If you want to relocate it anyway, use assembler of your choice and assemble it to another location or amend the DATA tables in Atari BASIC program demonstration. Maximum value for radius is 127, which is more than enough, because the circle with such radius will not be seen on the screen in whole anyway. If you choose wrong parameter values and consequently break the borders of the screen, don't worry, circle will be drawn anyway, but with its parts in different places. Experiment with the values for best results and your own fun. The included assembly language listing shows what is necessary for implementing circle algorithm, calculating coordinates and drawing pixels and circles on the screen. Fast circle drawing in pure Atari BASIC Magazine: Moj Mikro, 1989/3 Author : Zlatko Bleha Page : 27 - 31 Atari BASIC listing on disk (tokenized): M8903282.BAS Atari BASIC listing (listed): M8903282.LST Next example is demonstration of implementing mentioned circle algorithm in pure Atari BASIC. This program shows how much faster it is compared to classic program using sine and cosine functions from Atari BASIC (shown in last example). Use some valid values for coordinates and radius, for example: X=40, Y=40, R=30 X=130, Y=90, R=60 Slow circle drawing in Atari BASIC Magazine: Moj Mikro, 1989/3 Author : Zlatko Bleha Page : 27 - 31 Atari BASIC listing on disk (tokenized): M8903281.BAS Atari BASIC listing (listed): M8903281.LST This is classic example for drawing circles from Atari BASIC using sine and cosine functions. Unfortunatelly, this is very slow way of doing it and not recommended. Just use routine shown above and everybody will be happy Conclusion Returning back to first program with the fastest way of drawing circles... There is one more thing to note. In case you want to use PLOT subroutine, which is part of the main circle routine, then read following explanation. PLOT routine is written so it can be used easily from Atari BASIC program independently from main circle routine, by using like this: A=USR(30179,POK,X,Y) POK - 1 (drawing a pixel), 0 (erasing a pixel) X - X coordinate of the pixel Y - Y coordinate of the pixel The routine alone is not any faster than normal PLOT command from Atari BASIC, because USR command takes approximatelly 75% of whole execution. But, used as part of the main circle routine it does not matter anymore, because it is integrated in one larger entity. There the execution is very fast, with no overhead. PLOT routine is here for you to examine anyway. You never know if you will maybe need it in the future. Greetings, Gury Super fast circle routine.zip Edited April 8, 2010 by Gury Quote Link to comment Share on other sites More sharing options...
cas Posted April 8, 2010 Share Posted April 8, 2010 I present you super fast routine for drawing circles in graphics mode 8 and 8 + 16. [...] Greetings, Gury Hello Gury, thanks for posting this, this is very useful stuff! -- Carsten Quote Link to comment Share on other sites More sharing options...
Gury Posted April 8, 2010 Author Share Posted April 8, 2010 You are welcome, Cas, and thank you. I hope people will make good use of the routine and have some fun. I mistakely uploaded listed files as binary files. I will fix the problem when I come home. Anyway, here are the listings for you to look at. M8903284.LST 1 REM ******************************* 2 REM PROGRAM : SUPER FAST CIRCLE ROUTINE 3 REM AUTHOR : ZLATKO BLEHA 4 REM PUBLISHER: MOJ MIKRO MAGAZINE 5 REM ISSUE NO.: 1989, NO.3, PAGE 28 6 REM ******************************* 7 REM 10 FOR A=30000 TO 30288 20 READ B:C=C+B:POKE A,B 30 NEXT A 40 IF C<>28218 THEN ? "*** DATA ERROR ***":END 50 DATA 120,104,104,104,133,58,104,133,51,133 60 DATA 60,104,133,50,133,59,104,104,168,133 70 DATA 54,104,104,208,5,152,88,76,242,117 80 DATA 133,56,56,233,1,133,55,160,0,132 90 DATA 57,165,59,24,101,57,133,50,152,101 100 DATA 60,133,51,165,54,101,56,133,61,32 110 DATA 242,117,165,54,56,229,56,133,62,32 120 DATA 242,117,165,59,56,229,57,133,50,165 130 DATA 60,233,0,133,51,165,62,32,242,117 140 DATA 165,61,32,242,117,165,59,24,101,56 150 DATA 133,50,152,101,60,133,51,165,54,101 160 DATA 57,133,63,32,242,117,165,54,56,229 170 DATA 57,133,64,32,242,117,165,59,56,229 180 DATA 56,133,50,165,60,233,0,133,51,165 190 DATA 64,32,242,117,165,63,32,242,117,230 200 DATA 57,165,55,56,229,57,229,57,16,7 210 DATA 198,56,24,101,56,101,56,133,55,165 220 DATA 56,197,57,48,3,76,89,117,96,104 230 DATA 104,104,133,58,104,133,51,104,133,50 240 DATA 104,104,160,0,132,49,133,48,10,38 250 DATA 49,10,38,49,24,101,48,170,152,101 260 DATA 49,133,49,138,10,38,49,10,38,49 270 DATA 10,38,49,24,101,88,133,48,165,49 280 DATA 101,89,133,49,166,51,134,53,165,50 290 DATA 170,70,53,106,70,53,106,70,53,106 300 DATA 24,101,48,133,48,165,53,101,49,133 310 DATA 49,138,41,7,170,152,56,106,202,16 320 DATA 252,166,58,240,6,17,48,145,48,88 330 DATA 96,73,255,49,48,145,48,88,96 500 REM *************************** 501 REM * DEMONSTRATION PROGRAM * 502 REM *************************** 503 REM 510 GRAPHICS 8:SETCOLOR 2,0,0:COLOR 3 520 FOR A=2 TO 90 530 Q=USR(30000,1,A,A,A) 540 Q=USR(30000,1,319-A,A,A) 550 NEXT A 560 ? "PRESS ANY KEY TO CONTINUE" 570 IF PEEK(555)=0 THEN 570 580 ? :? :FOR A=2 TO 90 590 Q=USR(30000,1,319-A,159-A,A) 600 Q=USR(30000,1,A,159-A,A) 610 NEXT A 620 ? "PRESS ANY KEY TO CONTINUE" 630 IF PEEK(555)=0 THEN 630 640 GRAPHICS 8:SETCOLOR 2,0,0:COLOR 3 650 FOR A=2 TO 79 STEP 4 660 Q=USR(30000,1,100,A,A) 670 NEXT A 680 FOR A=82 TO 2 STEP -4 690 Q=USR(30000,1,A+100,A,A) 700 NEXT A 710 ? "PRESS ANY KEY TO START AGAIN" 720 IF PEEK(555)=0 THEN 720 730 GOTO 510 M8903282.LST 1 REM ******************************* 2 REM PROGRAM : FAST CIRCLE DRAWING 3 REM AUTHOR : ZLATKO BLEHA 4 REM PUBLISHER: MOJ MIKRO MAGAZINE 5 REM ISSUE NO.: 1989, NO.3, PAGE 29 6 REM ******************************* 7 REM 10 GRAPHICS 8:SETCOLOR 2,0,0:COLOR 3 20 ? "ENTER X, Y AND R" 30 INPUT X,Y,R 40 IF R=0 THEN PLOT X,Y:END 50 B=R:C=0:A=R-1 60 PLOT X+C,Y+B 70 PLOT X+C,Y-B 80 PLOT X-C,Y-B 90 PLOT X-C,Y+B 100 PLOT X+B,Y+C 110 PLOT X+B,Y-C 120 PLOT X-B,Y-C 130 PLOT X-B,Y+C 140 C=C+1 150 A=A+1-C-C 160 IF A>=0 THEN 190 170 B=B-1 180 A=A+B+B 190 IF B>=C THEN 60 M8903281.LST 1 REM ******************************* 2 REM PROGRAM : SLOW CIRCLE DRAWING 3 REM AUTHOR : ZLATKO BLEHA 4 REM PUBLISHER: MOJ MIKRO MAGAZINE 5 REM ISSUE NO.: 1989, NO.3, PAGE 29 6 REM ******************************* 7 REM 10 GRAPHICS 8:SETCOLOR 2,0,0:COLOR 3 20 FOR A=0 TO 6.28 STEP 0.02 30 X=SIN(A)*50+150 40 Y=COS(A)*50+80 50 PLOT X,Y 60 NEXT A CIRCLE.LST * * FAST CIRCLE DRAWING ROUTINE * * Author : Zlatko Bleha * Publisher: Moj Mikro magazine * Issue No.: 1989, No.3, Page 27 * * ----------------------------- * System variables on Page Zero * ----------------------------- * LO EQU $30 HI EQU $31 XLO EQU $32 XHI EQU $33 XLOH EQU $34 XHIH EQU $35 Y EQU $36 A EQU $37 B EQU $38 C EQU $39 POK EQU $3A X1 EQU $3B X2 EQU $3C YVIB EQU $3D YMAB EQU $3E YVIC EQU $3F YMAC EQU $40 * * ----------------------------------- * Taking circle parameters from stack * ----------------------------------- * ORG $7530 SEI PLA PLA PLA STA POK PLA STA XHI STA X2 PLA STA XLO STA X1 PLA PLA TAY STA Y PLA PLA BNE NEXT TYA CLI JMP PLOT NEXT STA B SEC SBC #$1 STA A LDY #$0 STY C * * ----------------------------- * PLOT X+C,Y+B * ----------------------------- * LOOP LDA X1 CLC ADC C STA XLO TYA ADC X2 STA XHI LDA Y ADC B STA YVIB JSR PLOT * * ----------------------------- * PLOT X+C,Y-B * ----------------------------- * LDA Y SEC SBC B STA YMAB JSR PLOT * * ----------------------------- * PLOT X-C,Y-B * ----------------------------- * LDA X1 SEC SBC C STA XLO LDA X2 SBC #$0 STA XHI LDA YMAB JSR PLOT * * ----------------------------- * PLOT X-C,Y+B * ----------------------------- * LDA YVIB JSR PLOT * * ----------------------------- * PLOT X+B,Y+C * ----------------------------- * LDA X1 CLC ADC B STA XLO TYA ADC X2 STA XHI LDA Y ADC C STA YVIC JSR PLOT * * ----------------------------- * PLOT X+B,Y-C * ----------------------------- * LDA Y SEC SBC C STA YMAC JSR PLOT * * ----------------------------- * PLOT X-B,Y-C * ----------------------------- * LDA X1 SEC SBC B STA XLO LDA X2 SBC #$0 STA XHI LDA YMAC JSR PLOT * * ----------------------------- * PLOT X-B,Y+C * ----------------------------- * LDA YVIC JSR PLOT * ----------------------------- INC C LDA A SEC SBC C SBC C BPL JUMP DEC B CLC ADC B ADC B JUMP STA A LDA B CMP C BMI END JMP LOOP END RTS * * ----------------------------- * PLOT routine * ----------------------------- * * ------------------------------------ * Taking parameters from stack in case * PLOT routine is called directly from * BASIC * ------------------------------------ * PLA PLA PLA STA POK PLA STA XHI PLA STA XLO PLA PLA LDY #$0 * * ----------------------------- * Beginning of the PLOT routine * ----------------------------- * * Calculating A*40 * ----------------------------- * PLOT STY HI STA LO ASL ROL HI ASL ROL HI CLC ADC LO TAX TYA ADC HI STA HI TXA ASL ROL HI ASL ROL HI ASL ROL HI * * ----------------------------- * A*40+VIDEO * ----------------------------- * CLC ADC $58 STA LO LDA HI ADC $59 STA HI * * ----------------------------- * X/8 * ----------------------------- * LDX XHI STX XHIH LDA XLO TAX LSR XHIH ROR LSR XHIH ROR LSR XHIH ROR * * ----------------------------- * A*40+VIDEO+X/8 * ----------------------------- * CLC ADC LO STA LO LDA XHIH ADC HI STA HI * * ----------------------------- * Calculating a location of * destination bit * ----------------------------- * TXA AND #$7 TAX TYA SEC ROT ROR DEX BPL ROT * * ----------------------------- * PLOT or UNPLOT? * ----------------------------- * LDX POK BEQ UNPLOT * * ----------------------------- * PLOT * ----------------------------- * ORA (LO),Y STA (LO),Y CLI RTS * * ----------------------------- * UNPLOT * ----------------------------- * UNPLOT EOR #$FF AND (LO),Y STA (LO),Y CLI RTS * ----------------------------- Quote Link to comment Share on other sites More sharing options...
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