wopr67 Posted January 8, 2022 Share Posted January 8, 2022 (edited) I am experimenting with sprites, and I have a simple two-line kernel. Every even-numbered scanline should show a solid red line (#255), while every odd-numbered scanline should show a dotted (#170) yellow line. I want to use GRP0 for both odd and even lines. Nothing I have tried works, and for the life of me, I can't figure out why. Here is my kernel: NextFrame VERTICAL_SYNC TIMER_SETUP 37 lda #$70 sta COLUBK lda #0 sta VDELP0 lda #0 sta GRP0 sta GRP1 TIMER_WAIT ldx #192 LVScan txa and #$01 beq .oddscan .evenscan lda #$48 ;red sta COLUP0 lda #255 sta GRP0 sta RESP0 jmp .join .oddscan lda #$1e ;yellow sta COLUP0 lda #170 sta GRP0 sta RESP0 .join sta WSYNC dex bne LVScan ; 30 lines of overscan TIMER_SETUP 32 lda #170 sta GRP0 TIMER_WAIT jmp NextFrame Any idea what the problem is? Thanks! Edited January 8, 2022 by wopr67 Quote Link to comment Share on other sites More sharing options...
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.