Hires Graphics

[carlsson]

The following program was listed in Elektronikvärlden, issue 6/7 June 1983. The hires routines were written by Thomas Magnusson, and presented as a ML listing, so VIC-MON or similar was required in order to input it. They used a lot of space describing the technique and some applications, but I think most people would have been better off with a Basic DATA loader.

The routines take 0.5K, the hires screen takes another 2K which leaves about 1K on an unexpanded machine. The routines would surely be possible to relocate or improve upon, but I haven't tried it yet. There may be better algorithms for e.g. line drawing too. Due to the limitations, there are no Basic extentions, so all routines are called via POKE and SYS:

Initialize screen
SYS 7168

Set dot colour to F
POKE 0,F:SYS 7212

Clear Screen
SYS 7223

Set Dot X,Y
POKE 0,X:POKE 1,Y:SYS 7346

Clear Dot X,Y
POKE 0,X:POKE 1,Y:SYS 7360

If Dot X,Y Then
POKE 0,X:POKE 1,Y:SYS 7373:IF PEEK(2) THEN

Draw Line X1,Y1 to X2,Y2
POKE 0,X1:POKE 1,Y1:POKE 2,X2:POKE 3,Y2:SYS 7576

Clear Line X1,Y1 to X2,Y2
POKE 0,X1:POKE 1,Y1:POKE 2,X2:POKE 3,Y2:SYS 7584

Save picture to tape
SYS 7592

Load picture from tape, set dot colour F, border R and background B
POKE 0,F:POKE 1,R:POKE 2,B:SYS 7610

Set dot colour F, border R and background B
POKE 0,F:POKE 1,R:POKE 2,B:SYS 7628

If you do SYS 7631, only border and background (equals POKE 36879) will change. The author suggests assigning variables such as:

SD=7346:POKE 0,X:POKE 1,Y:SYS SD

http://www.cbm.sfks.se/files/hires.d64

[vic user]

cool!

i have only very quickly tried it under VICE, but am looking forward to trying it on a real vic.

chris

[Mike]

I always was under the impression, that 'POKE and SYS' extensions for graphics didn't buy you much. After all, you still have to assign the pixel coordinates with POKE, while setting a pixel can also be done like in:

Code: Select all

AD=4352+INT(X/8)*192+Y:POKEAD,PEEK(AD)ORBI(XAND7)

provided, the array BI() is suitably initialised. The only thing that really gains from assembly - when the client program is written in BASIC - is the screen clear routine. To illustrate my point I went ahead yesterday, and wrote a function plotter:

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100 REM ** INITIALISE GRAPHICS
101 V=36864:FORT=0TO32:READA:POKE673+T,A:NEXT
102 POKEV+0,PEEK(60900)+2:POKEV+1,PEEK(60901)-2
103 POKEV+2,20:POKEV+3,25:POKEV+5,204:POKEV+15,27
104 FORY=0TO11:FORX=0TO19:POKE4096+Y*20+X,X*12+Y+16
105 POKE37888+Y*20+X,6:NEXT:NEXT:SYS673
106 DIMBI(7):S=1:FORT=0TO7:BI(7-T)=S:S=2*S:NEXT
107 :
110 REM ** SET SCREEN DIMENSIONS
111 XM=158:YM=190
112 :
120 REM ** SET DISPLAY RANGE
121 X0=-2.0:X1=3.0:XS=0.5
122 Y0=-5.0:Y1=5.0:YS=2.0
123 :
130 REM ** DRAW AXES AND SCALES
131 DX=(X1-X0)/XM:DY=(Y1-Y0)/YM
132 DEFFNX(Z)=INT((Z-X0)/DX+.5)
133 DEFFNY(Z)=INT((Z-Y0)/DY+.5)
134 XA=FNX(0):YA=FNY(0)
135 IFXA>=0ANDXA<=XMTHENXP=XA:FORYP=0TOYM:GOSUB200:NEXT
136 IFYA>=0ANDYA<=YMTHENYP=YA:FORXP=0TOXM:GOSUB200:NEXT
137 IFXA<0THENXA=0
138 IFXA>XMTHENXA=XM
139 IFYA<0THENYA=0
140 IFYA>YMTHENYA=YM
141 R=INT(X0/XS-1):S=INT(X1/XS+1)
142 FORT=RTOS:XP=FNX(XS*T):IFXP<0ORXP>XMTHEN144
143 FORYP=YA+(YA>0)TOYA-(YA<YM):GOSUB200:NEXT
144 NEXT
145 R=INT(Y0/YS-1):S=INT(Y1/YS+1)
146 FORT=RTOS:YP=FNY(YS*T):IFYP<0ORYP>YMTHEN148
147 FORXP=XA+(XA>0)TOXA-(XA<XM):GOSUB200:NEXT
148 NEXT
149 :
150 REM ** NUMBER OF FUNCTIONS
151 N=2:I=1
152 :
160 REM ** PLOT FUNCTIONS
161 XG=0:YF=-1
162 X=DX*XG+X0:YG=-1:POKE768,183:POKE769,2
163 ONIGOTO164,165,166,167,168,169,170,171,172,173
164 Y=(((8*X-14)*X-4)*X+8)*X+2:GOTO179
165 Y=X+1:GOTO179
166 Y=0:GOTO179
167 Y=0:GOTO179
168 Y=0:GOTO179
169 Y=0:GOTO179
170 Y=0:GOTO179
171 Y=0:GOTO179
172 Y=0:GOTO179
173 Y=0:GOTO179
178 :
179 YG=FNY(Y):IFYG<0ORYG>YMTHENYG=-1
180 REM ** NEVER RENUMBER THIS LINE
181 POKE768,58:POKE769,196:IFYG<>-1THENXP=XG:YP=YG:GOSUB200
182 IFYG=-1ORYF=-1ORABS(YF-YG)<2THEN185
183 YH=INT((YF+YG)/2):XP=XG-1:FORYP=YFTOYGSTEPSGN(YG-YF):IFYP=YHTHENXP=XG
184 GOSUB200:NEXT
185 YF=YG:XG=XG+1:IFXG<=XMTHEN162
186 I=I+1:IFI<=NTHEN161
190 REM ** WAIT FOR KEY TO FINISH
191 POKE198,0:WAIT198,1:SYS678
192 END
199 :
200 AD=4543+INT(XP/8)*192-YP:POKEAD,PEEK(AD)ORBI(XPAND7):RETURN
299 :
300 DATA169,17,133,252,169,0,133,251,168,162,15
301 DATA145,251,200,208,251,230,252,202,208,246,96
302 DATA169,180,133,20,169,0,133,21,76,163,200
399 :
400 REM ** VIC-20 FUNCTION PLOTTER
401 REM    WRITTEN 2006-01-29 BY
402 REM    MICHAEL KIRCHER

A RAM expansion is required. The program needs to be kept out of the place needed for the hires bitmap:

For +3K type: POKE 56,16:POKE648,16 + [RETURN] + [STOP/RESTORE].
For +8K (or more) type: POKE44,32:POKE8192,0:NEW + [RETURN]

before loading and running.

You see, most of the program doesn't have to do with access to the graphics. The pixel set routine is a subroutine in line 200, and I can live with the 6 lines at the beginning, that initialise and clear the graphics.

The ML part also contains a small routine that provides an ON ERROR GOTO 180 (if, for example, a calculation leads to a 'Division by Zero', the program still continues). Therefore the line 180 must not be renumbered.

Greetings,

Michael

Edit: In line 191 I replaced SYS8192 for another SYS that's guaranteed to contain a BRK instruction.

[Mike]

I had another programming session this weekend, thinking over a BASIC extension for the 160x192 hires mode.

In doing so I re-implemented the BASIC commands and function I once had in the MINIGRAFIK extension I mentioned here in another thread. I couldn't fit it into 256 Bytes however, mostly because 128x128 pixels (as in the original MINIGRAFIK) do have an easier address scheme, really. Then I replaced the relevant statements in the function plotter with the @-commands, and really was surprised, that the speed nearly doubled.

[...], but I think most people would have been better off with a Basic DATA loader.

So here it is: MINIGRAFIK V2, for 160x192 pixels. Beautifully cast into a DATA desert.

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[BASIC DATA loader deleted]

Cheers,

Michael

Edit: MINIGRAFIK V2 is obsolete. Please use V4.02 instead.

[vic user]

can't wait to type this in!

chris

[vic user]

wait a minute...

i think i will just cut and paste into notepad and rename it with a .prg extension

chris

[Boray]

Hmmm.... I don't think that will work. But you could probably use Björg's basic editor. Or you could use the Yape Plus/4 emulator to paste text into the emulator's screen (because I don't think you can do that in VICE??).

[GreyGhost]

I just tried the copy/paste feature on yape(060), and it worked to a point. The file was there, but it contained errors like:

Got an illegal quantity error- yape lost some of the commas, making the numbers run together.

Got out of data error- yape omitted numbers, I even saw where the data entry 144 was changed to 145.

Not bad, but alot of proofreading after the file is transfered. This would be a great upgrade for Vice as long as the bugs were worked out.

[Schlowski]

Cut&paste into my BasEdit and saved as Basic File:

http://www.stojalowski.de/files/minigrafx.prg

Didn't test it, but at least it looked ok

Björg

[carlsson]

Or use petcat in the VICE suite, or bastext, tok64 or some other standalone tokenizer.

[Mike]

I wrote two small example programs, that use the MINIGRAFIK extension. The first one does 3D-Graphics:

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10 DIMMI(159),MA(159)
11 FORX=0TO159:MI(X)=192:MA(X)=-1:NEXT
12 POKE36879,26:@ON:@CLR
13 FORY=30TO-30STEP-1:XP=INT(2*SQR(900-Y*Y)+.5)
14 FORX=-XPTOXP:XR=X/28:YR=Y/14:R=SQR(XR*XR+YR*YR)
15 F=COS(R)-COS(3*R)/3+COS(5*R)/5-COS(7*R)/7
16 FL=0:XP=80+X-Y:YP=96+2*Y-INT(40*F+.5)
17 IFMI(XP)>YPTHENMI(XP)=YP:FL=1
18 IFMA(XP)<YPTHENMA(XP)=YP:FL=1
19 IFFLANDYP>=0ANDYP<192THEN:@1,XP,YP
20 NEXT:NEXT:POKE36879,27
21 GETA$:IFA$=""THEN21
22 @RETURN

Set aside a pot of coffee, and watch. It runs ~22 Minutes to completion.


The second program portrays the Mandelbrot set:

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10 X=0:Y=0:X2=0:Y2=0:XY=0:R=0:J=0
11 DIMD(2,159),R(159),J(191):A=0:B=1:C=2
12 R0=-2.4:R1=+0.8:DR=(R1-R0)/160:FORS=0TO159:R(S)=R0+DR*S:NEXT
13 J0=-1.25:J1=+1.25:DJ=(J1-J0)/192:FORT=0TO191:J(191-T)=J0+DJ*T:NEXT
14 N=30
15 POKE36879,14:POKE646,1:@ON:@CLR
16 FORT=0TO191:J=J(T):FORS=0TO159:R=R(S):X=R:Y=J
17 FORI=1TON:X2=X*X:Y2=Y*Y:IFX2+Y2<4THENXY=X*Y:X=X2-Y2+R:Y=XY+XY+J:NEXT
18 D(C,S)=I:IFI<=NTHEN:@1,S,T
19 IFS<2ORT<2THEN28
20 IF@(S-1,T-1)=0THEN28
21 M=D(B,S-1)
22 IFD(B,S-2)<MANDD(B,S)<MTHEN27
23 IFD(A,S-2)<MANDD(C,S)<MTHEN27
24 IFD(C,S-2)<MANDD(A,S)<MTHEN27
25 IFD(A,S-1)<MANDD(C,S-1)<MTHEN27
26 GOTO28
27 @0,S-1,T-1
28 NEXTS:Z=A:A=B:B=C:C=Z:NEXT
29 GETA$:IFA$=""THEN29
30 POKE36879,27:POKE646,6:@RETURN

Here you should have more time to spare. It needs roughly 2 1/2 hours to finish. Alternatively run it in VICE and choose 'no speed limit'.

Cheers,

Michael

P.S.: The ':' between THEN and an '@' command is necessary. Otherwise you'll get a ?SYNTAX ERROR. This 'bug' is typical for this kind of BASIC extension.

[Mike]

Time for a bigger program. This example draws a 'minigrafik' logo. First the 'minigrafik' caption is read from DATA statements, and drawn using a line-routine (it's here only used to draw vertical lines).

Then two ellipses are drawn. I've assumed a 1.67:1 ratio for a VIC pixel on a TV set, so these ellipses actually should come out as circles. In VICE they'll appear more flattened.

Finally the gap between these two ellipses is filled with a flood fill routine.

The main program in the lines 1-9 shows, how to call the sub-routines in your own programs.

Greetings,

Michael

Code: Select all

1 REM ** MINIGRAFIK DEMO
2 POKE36879,14:POKE646,7:@ON:@CLR
3 READX:IFX<>-1THENX1=X+31:X2=X1:READA,B:Y1=113-A:Y2=113-B:GOSUB40:GOTO3
4 MX=80:MY=96:A=54:B=90:GOSUB50:A=57:B=95:GOSUB50
5 X=111:Y=173:GOSUB70
6 GETA$:IFA$=""THEN6
7 POKE36879,27:POKE646,6:@RETURN
8 END
9 :
10 DATA1,9,24,2,15,24,3,21,23,4,23,24,5,23,25,6,23,25,7,9,24,8,9,23,9,20,23,10,22,24
11 DATA11,23,25,12,23,25,13,23,25,14,10,24,15,9,22,16,9,10,17,10,11
12 :
13 DATA19,11,22,19,29,30,20,9,24,20,29,30,21,9,10,22,10,11
14 :
15 DATA25,9,24,26,9,24,27,19,22,28,22,24,29,23,25,30,23,25,31,23,25,32,10,24,33,9,22
16 DATA34,9,10,35,10,11
17 :
18 DATA37,11,22,37,29,30,38,9,24,38,29,30,39,9,10,40,10,11
19 :
20 DATA43,13,18,44,2,3,44,11,21,45,1,3,45,10,12,45,20,23,46,1,3,46,9,11,46,22,24,47,1,3
21 DATA47,9,11,47,23,24,48,2,3,48,10,11,48,23,25,49,2,4,49,11,12,49,23,25,50,3,10
22 DATA50,12,15,50,23,25,51,6,25,52,19,24
23 :
24 DATA55,9,24,56,11,24,57,20,23,58,22,24,59,23,25,60,23,25
25 :
26 DATA63,13,18,64,11,22,65,10,12,65,20,23,66,9,11,66,22,24,67,9,11,67,23,24,68,10,12
27 DATA68,23,25,69,11,13,69,23,25,70,10,25,71,9,24,72,9,10,73,10,11
28 :
29 DATA71,1,3,72,1,3,73,1,3,74,2,4,74,23,24,75,3,7,75,23,24,76,4,30,77,11,32,78,23,24
30 DATA78,31,33,79,23,24,79,32,34,80,32,34,81,33,33
31 :
32 DATA82,11,22,82,29,30,83,9,24,83,29,30,84,9,10,85,10,11
33 :
34 DATA88,9,34,89,16,34,90,16,18,90,21,23,91,14,18,91,22,24,92,12,15,92,17,19,92,23,25
35 DATA93,10,13,93,18,20,93,23,25,94,9,11,94,19,24,95,9,11,95,20,23,96,10,11
36 :
37 DATA-1
38 :
39 REM ** LINE DRAW
40 DX=X2-X1:DY=Y2-Y1:IFDX=0ANDDY=0THEN:@1,X1,Y1:RETURN
41 IFABS(DX)<ABS(DY)THEN43
42 M=DY/DX:B=Y1-M*X1+.5:FORX=X1TOX2STEPSGN(X2-X1):@1,X,INT(M*X+B):NEXT:RETURN
43 M=DX/DY:B=X1-M*Y1+.5:FORY=Y1TOY2STEPSGN(Y2-Y1):@1,INT(M*Y+B),Y:NEXT:RETURN
44 :
49 REM ** ELLIPSE DRAW
50 X=0:Y=B:S=B*B:T=A*A*(2*Y-1):U=2*B*B:V=2*A*A:E=0
51 X1=MX+X:F1=X1>=0ANDX1<160
52 Y1=MY+Y:F2=Y1>=0ANDY1<192:IFF1ANDF2THEN:@1,X1,Y1
53 Y2=MY-Y:F3=Y2>=0ANDY2<192:IFF1ANDF3THEN:@1,X1,Y2
54 X2=MX-X:F4=X2>=0ANDX2<160:IFF4ANDF3THEN:@1,X2,Y2
55 IFF4ANDF2THEN:@1,X2,Y1
56 IFX=AANDY=0THENRETURN
57 F=E+S:D=0
58 G=F-T:IFABS(F)>ABS(G)THENF=G:D=1
59 G=E-T:IFABS(F)>ABS(G)THENF=G:D=2
60 E=F
61 IFD<2THENX=X+1:S=S+U
62 IFD>0THENY=Y-1:T=T-V
63 GOTO51
64 :
69 REM ** FLOOD FILL
70 Q$=CHR$(X)+CHR$(Y)
71 IFQ$=""THENRETURN
72 X=ASC(MID$(Q$,1,1)):Y=ASC(MID$(Q$,2,1))
73 Q$=MID$(Q$,3):GOSUB82:IFPTHEN71
74 X=X-1:GOSUB82:IFNOTPTHEN74
75 X=X+1:U=0:D=0
76 @1,X,Y:Y=Y-1:GOSUB82:IFPTHENU=0:GOTO78
77 IFNOTUTHENQ$=Q$+CHR$(X)+CHR$(Y):U=-1
78 Y=Y+2:GOSUB82:IFPTHEND=0:GOTO80
79 IFNOTDTHENQ$=Q$+CHR$(X)+CHR$(Y):D=-1
80 Y=Y-1:X=X+1:GOSUB82:IFNOTPTHEN76
81 GOTO71
82 IFX<0ORX>159ORY<0ORY>191THENP=-1:RETURN
83 P=-@(X,Y):RETURN
84 :
99 REM ** MINIGRAFIK DEMO 2006-03-23 BY MICHAEL KIRCHER

[Jeff-20]

"@"?

[Schlowski]

You need to load and run the "graphik engine" before running Mikes program - see some entries above...

Björg

[Mike]

"@"?

The reason why the thread runs under 'ML and other programs'. You'll need to run my MINIGRAFIK extension first. This is the DATA loader further up this topic. You can then use the following commands:

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@ON               : initialise 160x192 pixel hires screen
@CLR              : clear hires screen, and set colour RAM
@RETURN           : back to text mode
@<colour>,<x>,<y> : set point in <colour> at <x>,<y>

<colour>, <x>, and <y> can be numbers, variables, or other arbitrary expressions.

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<colour>: =0, clear point; =1, set point
<x>: between 0 and 159
<y>: between 0 and 191

and finally, as a function:

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@(<x>,<y>)        : returns 0 if pixel is clear at <x>,<y>; 1 if it is set.

Greetings,

Michael