Create a custom theme
Back to work on the TI-83 Plus port of BBC BASIC! To complement the graphics viewport I've added support for text viewports — this lets you define the area the text console uses. The following VDU commands are now supported:
The above screenshots defines the graphics viewport to fill the left hand side of the screen and shunts the text viewport over to the right half, using the following code:
The above code allocates 8 bytes of memory (DIM ball 7) then copies the sprite data to it by use of the ? indirection operator. This is a little laborious, so in reality you'd probably store your sprites in a binary file external to the main program, and might load them like this:
(Note FN_loadSprite() at the end of the program). The result is the following:
Next up: drawing text at the graphics cursor position (as sprites).
- VDU 24,<left>;<top>;<right>;<bottom>;
Define a graphics viewport. - VDU 28,<left>,<top>,<right>,<bottom>
Define a text viewport. - VDU 26
Reset both viewports to their default settings (full screen). - VDU 29,<x>;<y>;
Defines the graphics origin.
The above screenshots defines the graphics viewport to fill the left hand side of the screen and shunts the text viewport over to the right half, using the following code:
VDU 24,0;0;47;63;I've also added simple sprite drawing to BBC BASIC's PLOT command. PLOT usually takes a shape type and two coordinates, but for sprites (shapes 208..215) I've added an extra parameter - the address of the sprite data to use.
VDU 28,12,0,23,9
VDU 29,24;32;
10 DIM ball 7
20 ball?0=&3C
30 ball?1=&5E
40 ball?2=&8F
50 ball?3=&DF
60 ball?4=&FF
70 ball?5=&FF
80 ball?6=&7E
90 ball?7=&3C
100 *REFRESH OFF
110 REPEAT
120 CLG
130 T=TIME/100
140 FOR P=0 TO 5
150 A=P/3*PI+T
160 X=16*SIN(A)+44
170 Y=16*COS(A)+28
180 PLOT 213,X,Y,ball
190 NEXT
200 *REFRESH
210 UNTIL INKEY(0)<>-1
220 *REFRESH ON
The above code allocates 8 bytes of memory (DIM ball 7) then copies the sprite data to it by use of the ? indirection operator. This is a little laborious, so in reality you'd probably store your sprites in a binary file external to the main program, and might load them like this:
10 ball%=FN_loadSprite("SPRITES",0)
20 face%=FN_loadSprite("SPRITES",1)
30 *REFRESH OFF
40 REPEAT
50 CLG
60 T=TIME/100
70 FOR P=0 TO 5
80 A=P/3*PI+T
90 X=16*SIN(A)+44
100 Y=16*COS(A)+28
110 PLOT 213,X,Y,ball%
120 NEXT
130 PLOT 213,44,28,face%
140 *REFRESH
150 UNTIL INKEY(0)<>-1
160 *REFRESH ON
170 END
180 DEF FN_loadSprite(f$,i%)
190 fh%=OPENIN(f$)
200 PTR#fh%=i%*8
210 DIM spr 7
220 FOR j%=0 TO 7
230 spr?j%=BGET#fh%
240 NEXT j%
250 CLOSE#fh%
260 =spr
270 ENDPROC
(Note FN_loadSprite() at the end of the program). The result is the following:
Next up: drawing text at the graphics cursor position (as sprites).
I'm not complaining, I like them. It makes this journal unique as you usually don't see so much animation in the others.