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| author | Miquel Sabaté Solà <mssola@mssola.com> | 2026-02-28 00:26:07 +0100 |
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| committer | Miquel Sabaté Solà <mssola@mssola.com> | 2026-02-28 00:26:07 +0100 |
| commit | c87cad0b873c2f1c45c420dd96f828f35de6a4ba (patch) | |
| tree | edc2a1b94be38b5f0c1be3a09f39c4a92f3e6972 /src/enemies.s | |
| parent | 90c2a76952e2f2bb30f41e5218e2f5e02d78b8d2 (diff) | |
| download | jetpac.nes-c87cad0b873c2f1c45c420dd96f828f35de6a4ba.tar.gz jetpac.nes-c87cad0b873c2f1c45c420dd96f828f35de6a4ba.zip | |
Move the 'extra' initialization to a function
This allows us to be able to initialize each enemy separately, giving a
more random appearance to it all. This will also come in handy whenever
we want to make enemies re-appear.
Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com>
Diffstat (limited to 'src/enemies.s')
| -rw-r--r-- | src/enemies.s | 104 |
1 files changed, 53 insertions, 51 deletions
diff --git a/src/enemies.s b/src/enemies.s index 23ae18f..c93f1c2 100644 --- a/src/enemies.s +++ b/src/enemies.s @@ -92,58 +92,15 @@ lda movement_hi, x sta zp_enemy_movement_fn + 1 - ;; TODO: rest of the enemies. - ;; TODO: there are ways to optimize this + ;; Initialize the enemy arg, which is always 1 except for homing + ;; attacks. + ldy #1 txa - beq @init_basic - cmp #1 - beq @init_bounce_1 - cmp #2 - beq @init_erratic cmp #3 - beq @init_homing - cmp #5 - beq @init_bounce_2 - cmp #6 - __fallthrough__ @init_basic - - @init_basic: - lda #1 - sta Enemies::zp_enemy_arg - jsr Prng::random_valid_y_coordinate - and #$0F - ora #$11 - bne @set - @init_erratic: - lda #1 - sta Enemies::zp_enemy_arg - jsr Prng::random_valid_y_coordinate - and #$01 - jmp @set - @init_homing: - lda #1 - sta Enemies::zp_enemy_arg - jsr Prng::random_valid_y_coordinate - and #$01 - ora #$10 - jmp @set - @init_bounce_1: - lda #1 - sta Enemies::zp_enemy_arg - jsr Prng::random_valid_y_coordinate - and #$01 - jmp @set - @init_bounce_2: - lda #2 - sta Enemies::zp_enemy_arg - jsr Prng::random_valid_y_coordinate - and #$01 - __fallthrough__ @set - - @set: - ;; The 'init_pool' wants an argument which is the 'extra' state to be - ;; set up for all enemies of the pool. - sta Globals::zp_arg0 + bne @set_enemy_arg + iny + @set_enemy_arg: + sty Enemies::zp_enemy_arg __fallthrough__ init_pool .endproc @@ -185,8 +142,10 @@ sta zp_enemies_pool_base, x ;; And set the 'extra' state as passed down by the 'init' function. + stx Globals::zp_tmp0 + jsr generate_extra + ldx Globals::zp_tmp0 inx - lda Globals::zp_arg0 sta zp_enemies_pool_base, x ;; Next enemy! @@ -197,6 +156,49 @@ rts .endproc + ;; Generate a value for the 'extra' value depending on the current level + ;; kind. The result is left in 'a'. + ;; + ;; NOTE: the 'x' register is touched, while the 'y' register is not. + .proc generate_extra + ;; TODO: rest of the enemies. + lda Globals::zp_level_kind + beq @init_basic + cmp #1 + beq @init_bounce_1 + cmp #2 + beq @init_erratic + cmp #3 + beq @init_homing + cmp #5 + beq @init_bounce_2 + cmp #6 + __fallthrough__ @init_basic + + @init_basic: + jsr Prng::random_valid_y_coordinate + and #$0F + ora #$11 + rts + @init_erratic: + jsr Prng::random_valid_y_coordinate + and #$01 + rts + @init_homing: + jsr Prng::random_valid_y_coordinate + and #$01 + ora #$10 + rts + @init_bounce_1: + jsr Prng::random_valid_y_coordinate + and #$01 + rts + @init_bounce_2: + jsr Prng::random_valid_y_coordinate + and #$01 + rts + .endproc + ;; Update the state and movement of all active enemies. ;; ;; NOTE: this function does not do collision checking with bullets as |