; Uses the 40x48d page1/page2 every-1-scanline pageflip mode ; self modifying code to get some extra colors (pseudo 40x192 mode) ; by deater (Vince Weaver) credits: ;=================== ; init screen jsr TEXT jsr HOME bit KEYRESET ;=================== ; init vars lda #0 sta DRAW_PAGE ;================== ; setup graphics jsr create_update_type1 jsr setup_rasterbars ;============================= ; Load graphic page0 lda #credits_low sta GBASH lda #$c ; load image to $c00 jsr load_rle_gr lda #4 sta DRAW_PAGE jsr gr_copy_to_current ; copy to page1 ; GR part bit PAGE1 bit LORES ; 4 bit SET_GR ; 4 bit FULLGR ; 4 ; jsr wait_until_keypressed ;============================= ; Load graphic page1 lda #credits_high sta GBASH lda #$c ; load to $c00 jsr load_rle_gr lda #0 sta DRAW_PAGE jsr gr_copy_to_current ; ; GR part bit PAGE0 ; jsr wait_until_keypressed ;============================== ; setup graphics for vapor lock ;============================== jsr vapor_lock ; vapor lock returns with us at beginning of hsync in line ; 114 (7410 cycles), so with 5070 lines to go ; GR part bit LORES ; 4 bit SET_GR ; 4 bit FULLGR ; 4 jsr gr_copy_to_current ; 6+ 9292 ; 5070 + 4550 = 9620 ; 9292 ; 12 ; 6 ; ==== ; 310 ; - 3 for jmp ; 307 ; Try X=9 Y=6 cycles=307 ldy #6 ; 2 tloopA: ldx #9 ; 2 tloopB: dex ; 2 bne tloopB ; 2nt/3 dey ; 2 bne tloopA ; 2nt/3 jmp credits_loop ; 3 .align $100 ;================================================ ; Display Loop ;================================================ ; each scan line 65 cycles ; 1 cycle each byte (40cycles) + 25 for horizontal ; Total of 12480 cycles to draw screen ; Vertical blank = 4550 cycles (70 scan lines) ; Total of 17030 cycles to get back to where was ; We want to alternate between page1 and page2 every 65 cycles ; vblank = 4550 cycles to do scrolling credits_loop: jsr $9000 ;====================================================== ; We have 4550 cycles in the vblank, use them wisely ;====================================================== ; 4550 -- VBLANK ; -582 -- erase 22+4*(8+6+126) = 582 ; -696 -- move+draw 4*(16+26+6+126) = 696 ; -10 -- keypress ; -12 -- call/return of draw code ;======= ; 3250 pad_time: ; we erase, then draw ; doing a blanket erase of all 128 lines would cost 3459 cycles! ;========================= ; ERASE ;========================= lda #$00 ; 2 sta smc_raster_color1_1+1 ; 4 sta smc_raster_color1_2+1 ; 4 sta smc_raster_color2_1+1 ; 4 sta smc_raster_color2_2+1 ; 4 sta smc_raster_color3_1+1 ; 4 ;============= ; 22 ; erase red lda red_x ; 4 and #$7f ; 2 tax ; 2 jsr draw_rasterbar ; 6+126 ; erase yellow lda yellow_x ; 4 and #$7f ; 2 tax ; 2 jsr draw_rasterbar ; 6+126 ; erase green lda green_x ; 4 and #$7f ; 2 tax ; 2 jsr draw_rasterbar ; 6+126 ; erase red lda blue_x ; 4 and #$7f ; 2 tax ; 2 jsr draw_rasterbar ; 6+126 ;========================= ; MOVE and DRAW ;========================= ;============ ; move red ldy red_x ; 4 lda movement_table,Y ; 4 sta red_x ; 4 and #$7f ; 2 tax ; 2 ;========== ; 16 ; draw red lda #$33 ; 2 sta smc_raster_color1_1+1 ; 4 sta smc_raster_color1_2+1 ; 4 lda #$bb ; 2 sta smc_raster_color2_1+1 ; 4 sta smc_raster_color2_2+1 ; 4 lda #$ff ; 2 sta smc_raster_color3_1+1 ; 4 ;============= ; 26 jsr draw_rasterbar ; 6+126 ;============ ; move yellow ldy yellow_x ; 4 lda movement_table,Y ; 4 sta yellow_x ; 4 and #$7f ; 2 tax ; 2 ;========== ; 16 ; draw yellow lda #$88 ; 2 sta smc_raster_color1_1+1 ; 4 sta smc_raster_color1_2+1 ; 4 lda #$dd ; 2 sta smc_raster_color2_1+1 ; 4 sta smc_raster_color2_2+1 ; 4 lda #$ff ; 2 sta smc_raster_color3_1+1 ; 4 ;============= ; 26 jsr draw_rasterbar ; 6+126 ;============ ; move green ldy green_x ; 4 lda movement_table,Y ; 4 sta green_x ; 4 and #$7f ; 2 tax ; 2 ;========== ; 16 ; draw green lda #$44 ; 2 sta smc_raster_color1_1+1 ; 4 sta smc_raster_color1_2+1 ; 4 lda #$cc ; 2 sta smc_raster_color2_1+1 ; 4 sta smc_raster_color2_2+1 ; 4 lda #$ff ; 2 sta smc_raster_color3_1+1 ; 4 ;============= ; 26 jsr draw_rasterbar ; 6+126 ;============ ; move blue ldy blue_x ; 4 lda movement_table,Y ; 4 sta blue_x ; 4 and #$7f ; 2 tax ; 2 ;========== ; 16 ; draw blue lda #$22 ; 2 sta smc_raster_color1_1+1 ; 4 sta smc_raster_color1_2+1 ; 4 lda #$66 ; 2 sta smc_raster_color2_1+1 ; 4 sta smc_raster_color2_2+1 ; 4 lda #$ff ; 2 sta smc_raster_color3_1+1 ; 4 ;============= ; 26 jsr draw_rasterbar ; 6+126 ;============================ ; WAIT for VBLANK to finish ;============================ ; Try X=71 Y=9 cycles=3250 ldy #9 ; 2 tloop1: ldx #71 ; 2 tloop2: dex ; 2 bne tloop2 ; 2nt/3 dey ; 2 bne tloop1 ; 2nt/3 lda KEYPRESS ; 4 bpl cno_keypress ; 3 jmp credits_loop cno_keypress: jmp credits_loop ; 3 ;======================== ; Draw a rasterbar ; unroll as memory is free! haha ;======================== ; X is location ; 2+22+24+24+24+24+6 = 126 draw_rasterbar: ldy #0 ; 2 ;==== lda y_lookup_l,X ; 4 sta OUTL ; 3 lda y_lookup_h,X ; 4 sta OUTH ; 3 smc_raster_color1_1: lda #$33 ; 2 sta (OUTL),Y ; 6 ;============ ; 22 inx ; 2 lda y_lookup_l,X ; 4 sta OUTL ; 3 lda y_lookup_h,X ; 4 sta OUTH ; 3 smc_raster_color2_1: lda #$bb ; 2 sta (OUTL),Y ; 6 inx ; 2 lda y_lookup_l,X ; 4 sta OUTL ; 3 lda y_lookup_h,X ; 4 sta OUTH ; 3 smc_raster_color3_1: lda #$ff ; 2 sta (OUTL),Y ; 6 inx lda y_lookup_l,X ; 4 sta OUTL ; 3 lda y_lookup_h,X ; 4 sta OUTH ; 3 smc_raster_color2_2: lda #$bb ; 2 sta (OUTL),Y ; 6 inx lda y_lookup_l,X ; 4 sta OUTL ; 3 lda y_lookup_h,X ; 4 sta OUTH ; 3 smc_raster_color1_2: lda #$33 ; 2 sta (OUTL),Y ; 6 rts ; 6 red_x: .byte $10 yellow_x: .byte $20 green_x: .byte $30 blue_x: .byte $40