diff options
Diffstat (limited to 'src/enemies.s')
| -rw-r--r-- | src/enemies.s | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/src/enemies.s b/src/enemies.s new file mode 100644 index 0000000..ab67ccd --- /dev/null +++ b/src/enemies.s @@ -0,0 +1,58 @@ +.segment "CODE" + +.scope Enemies + ;; Maximum amount of enemies allowed on screen at the same time. + ENEMIES_POOL_CAPACITY = 3 + + ;; The capacity of the bullets pool in bytes. + ENEMIES_POOL_CAPACITY_BYTES = ENEMIES_POOL_CAPACITY * 3 + + ENEMIES_INITIAL_X = $F0 + + ;; TODO: 3 bytes a la bullets + zp_enemies_pool_base = $60 + + zp_enemies_timer = $D0 + zp_enemies_pool_size = $D1 + + .proc init + ldx #0 + stx zp_enemies_timer + + ldy #ENEMIES_POOL_CAPACITY + @enemies_init_loop: + lda #0 + sta zp_enemies_pool_base, x + + inx + lda #$80 ; TODO: random + sta zp_enemies_pool_base, x + + inx + lda #ENEMIES_INITIAL_X + sta zp_enemies_pool_base, x + + inx + + dey + bne @enemies_init_loop + + lda #ENEMIES_POOL_CAPACITY + sta zp_enemies_pool_size + + rts + .endproc + + ;; Definitions for all the enemy types. These are just the tile IDs for each + ;; case. Note that some of them have $FF, which is because they span 2 + ;; sprites instead of 4. +tiles: + .byte $26, $27, $36, $37 + .byte $28, $29, $38, $39 + .byte $24, $25, $34, $35 + .byte $2A, $2B, $3A, $3B + .byte $31, $32, $FF, $FF + .byte $41, $42, $FF, $FF + .byte $2C, $2D, $3C, $3D + .byte $2E, $2F, $3E, $3F +.endscope |