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author | Jesse Luehrs <doy@tozt.net> | 2014-10-09 11:41:50 -0400 |
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committer | Jesse Luehrs <doy@tozt.net> | 2014-10-09 11:42:11 -0400 |
commit | e039f249a80f9068518579c06e8b4a8cef7b7339 (patch) | |
tree | ce07d49f2dc3c08e6e6a6ec88c632e962c06a51a | |
parent | 88e83296cd6b401bfb794e3b3869063a309ef172 (diff) | |
download | nes-snake-e039f249a80f9068518579c06e8b4a8cef7b7339.tar.gz nes-snake-e039f249a80f9068518579c06e8b4a8cef7b7339.zip |
add an apple in a random location
-rw-r--r-- | main.s | 29 | ||||
-rw-r--r-- | sprites.chr | bin | 8192 -> 8192 bytes |
2 files changed, 27 insertions, 2 deletions
@@ -41,6 +41,7 @@ direction DB ; 0: up, 1: down, 2: left, 3: right frame_skip DB frame_count DB rand_state DB +apple INSTANCEOF point .ENDE ; }}} ; }}} @@ -148,11 +149,11 @@ NMI: LDA game_state BEQ reset_sprites CMP #$01 - BEQ draw_head + BEQ draw_game CMP #$02 BEQ end_nmi -draw_head: +draw_game: LDY #$01 LDA (head), y STA $0200 @@ -163,12 +164,23 @@ draw_head: LDY #$00 LDA (head), y STA $0203 + + LDA apple.y + STA $0204 + LDA #$07 + STA $0205 + LDA #$00 + STA $0206 + LDA apple.x + STA $0207 JMP do_dmi reset_sprites: LDA #$FE STA $0200 STA $0203 + STA $0204 + STA $0207 do_dmi: LDA #$00 @@ -321,6 +333,19 @@ start_game: ; {{{ LDY #$01 STA (head), y + JSR rand + LDA rand_state + AND #%01111000 + CLC + ADC #$40 + STA apple.x + JSR rand + LDA rand_state + AND #%01111000 + CLC + ADC #$3D + STA apple.y + - BIT $2002 BPL - diff --git a/sprites.chr b/sprites.chr Binary files differindex 894b4b5..9f333de 100644 --- a/sprites.chr +++ b/sprites.chr |