Thank you Dennis and Andrew for your help!
After the corrections the code runs just fine.
Thanks!
11/3/02 9:51:51 PM, "Dennis Debro" <ddebro@xxxxxxxxxxxxx> wrote:
>Hi Rico! Welcome aboard.
>
>> I am learning how to draw a playfield. I have read Nick's famous
>> playfield example and tried different variations that have
>> been posted on the list. I have written a small program
>> which only purpose is to draw a rectangle repeatedly
>> from the top to the bottom of the screen (without worrying about the
>> reflected portion of the screen). I initialized the playflied
>> registers to draw something like this:
>>
>> * * * * * * * * * * * * * * * *
>> * *
>> * *
>> * *
>> * *
>> * *
>> * *
>> * * * * * * * * * * * * * * * *
>
>Actually your rectangle is more like
> * * * * * * * * * * * * * * * * * * * *
> * * *
> * * *
> * * *
> * * *
> * * *
> * * *
> * * * * * * * * * * * * * * * * * * * *
>
>Change your $A0 to $80 for PFData2 to get the rectangle you're expecting
>
>See my comments below
>
>> ; Learning atari playfields
>> ;
>> ; Objective: Draw a rectangle many times
>> ; using the playfield registers.
>> ;
>>
>> processor 6502
>> include eckvcs.h
>> org $F000
>>
>> START
>> SEI
>> CLD
>> LDX #$FF
>> TXS
>> LDA #0
>>
>> CLEARMEM
>> STA 0,X
>> DEX
>> BNE CLEARMEM
>> LDA #$00 ; SET BACKGROUND BLACK
>> STA COLUBK
>> LDA #$1E ; SET PLAYFIELD YELLOW
>> STA COLUPF
>>
>> MAINLOOP
>> LDA #2 ; TURN ON VSYNC
>> STA VSYNC
>> STA WSYNC
>> STA WSYNC
>> STA WSYNC
>>
>> LDA #43
>> STA TIM64T
>> LDA #0 ; TURN OFF VSYNC
>> STA VSYNC
>>
>> VBLANKTIME
>> LDA INTIM
>> BNE VBLANKTIME
>
> STA WSYNC ; end the current scan line
> STA VBLANK ; end VBLANK period
>>
>> LDX #7 ; Use X register to count
>> ; eight playfield lines
>> ; to draw.
>> LDY #191
>>
>> SCANLOOP
>> STA WSYNC ; Accumulator is still 0
>; STA VBLANK ; remove the VBLANK from your drawing loop
>>
>> LDA PFData0,X
>> STA PF0
>> LDA PFData1,X
>> STA PF1
>> LDA PFData2,X
>> STA PF2
>>
>> DEX ; Decrement X.
>> BNE SKIPINITX ; If X != 0 then skip next line
>> LDX #7 ; Repeat playfield drawing
>> ; by setting X to decimal 7.
>>
>> SKIPINITX
>>
>> DEY
>> BNE SCANLOOP
>>
>> LDX #30
> STX WSYNC ; end current scan line
> STX VBLANK ; Make TIA output invisible (bit 1 is set to 1)
> STY PF0 ; clear the playfield registers
> STY PF1
> STY PF2
>>
>> OVERSCAN
>> STA WSYNC
>> DEX
>> BNE OVERSCAN
>>
>> JMP MAINLOOP
>>
>> org $FF00 ; GRAPHICS DATA STARTS HERE
>>
>> ; Playfield graphic is supposed to look like this:
>> ;
>> ; * * * * * * * * * * * * * * * *
>> ; * *
>> ; * *
>> ; * *
>> ; * *
>> ; * *
>> ; * *
>> ; * * * * * * * * * * * * * * * *
>> ;
>>
>> PFData0
>> .byte $F0,$10,$10,$10,$10,$10,$10,$F0
>>
>> PFData1
>> .byte $FF,$00,$00,$00,$00,$00,$00,$FF
>>
>> PFData2
>> .byte $FF,$A0,$A0,$A0,$A0,$A0,$A0,$FF
>>
>>
>> ORG $FFFC
>> .WORD START
>> .WORD START
>
>
>
>----------------------------------------------------------------------------------------------
>Archives (includes files) at http://www.biglist.com/lists/stella/archives/
>Unsub & more at http://www.biglist.com/lists/stella/
>
>
>
----------------------------------------------------------------------------------------------
Archives (includes files) at http://www.biglist.com/lists/stella/archives/
Unsub & more at http://www.biglist.com/lists/stella/
