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| author | Jesse Luehrs <doy@tozt.net> | 2014-10-11 23:25:28 -0400 |
|---|---|---|
| committer | Jesse Luehrs <doy@tozt.net> | 2014-10-11 23:25:28 -0400 |
| commit | bb2990f82f5aa901f0aa83e0bec4658d68548663 (patch) | |
| tree | a3420e9548cbed0c31f6a7fa89a70dc28f146189 | |
| parent | 33d3f4266229687d7d48fcaf90da51957bf99859 (diff) | |
| download | nes-snake-bb2990f82f5aa901f0aa83e0bec4658d68548663.tar.gz nes-snake-bb2990f82f5aa901f0aa83e0bec4658d68548663.zip | |
move all game logic out of the nmi interrupt
drawing is now done in the main game code, by writing into the $07 page,
and the nmi interrupt now just steps through that page and does the
drawing actions described there
| -rw-r--r-- | main.s | 82 |
1 files changed, 57 insertions, 25 deletions
@@ -48,6 +48,7 @@ vram_addr_low DB vram_addr_high DB body_test_x DB body_test_y DB +num_draws DB .ENDE ; }}} ; }}} @@ -169,34 +170,33 @@ NMI: JMP end_nmi draw_game: - LDX #$00 - JSR draw_sprite_at_head - LDA head_x - SEC - SBC length - STA head_x - LDA head_y - SEC - SBC length - STA head_y - LDX #$20 - JSR draw_sprite_at_head - LDA head_x - CLC - ADC length - STA head_x - LDA head_y +- LDA #$00 CLC - ADC length - STA head_y + ADC num_draws + ADC num_draws + ADC num_draws + SEC + SBC #$03 + TAX + LDA $0700, x + STA $2006 + INX + LDA $0700, x + STA $2006 + INX + LDA $0700, x + STA $2007 + LDX num_draws + DEX + STX num_draws + CPX #$00 + BNE - LDA #$20 STA $2006 LDA #$00 STA $2006 - JMP do_dma - do_dma: LDA #$00 STA $2003 @@ -366,6 +366,26 @@ eat_apple: + JSR new_apple end_game_loop: + LDX #$00 + JSR draw_sprite_at_head + LDA head_x + SEC + SBC length + STA head_x + LDA head_y + SEC + SBC length + STA head_y + LDX #$20 + JSR draw_sprite_at_head + LDA head_x + CLC + ADC length + STA head_x + LDA head_y + CLC + ADC length + STA head_y RTS ; }}} read_controller1: ; {{{ ; latch @@ -588,13 +608,25 @@ draw_sprite_at_head: ; {{{ ADC #$00 STA vram_addr_high + TXA + TAY + LDA #$00 + ADC num_draws + ADC num_draws + ADC num_draws + TAX LDA vram_addr_high - STA $2006 + STA $0700, x + INX LDA vram_addr_low - STA $2006 + STA $0700, x + INX + TYA + STA $0700, x - TXA - STA $2007 + LDX num_draws + INX + STX num_draws RTS ; }}} test_body_collision ; {{{ |