diff options
| -rw-r--r-- | src/driver.s | 32 | ||||
| -rw-r--r-- | src/jetpac.s | 6 | ||||
| -rw-r--r-- | src/player.s | 55 | ||||
| -rw-r--r-- | src/vectors.s | 5 |
4 files changed, 91 insertions, 7 deletions
diff --git a/src/driver.s b/src/driver.s index bb0303f..00e807c 100644 --- a/src/driver.s +++ b/src/driver.s @@ -9,6 +9,11 @@ zp_player_timer = $30 PLAYER_TIMER_VALUE = HZ * 2 + .ifdef PAL + ;; Frame counter which resets every 5 frames. + zp_pal_counter = $31 + .endif + ;; Switch from the title screen to the main street. Note that this function ;; is to be called with the PPU disabled. If that's not the case, then it ;; will set the proper values to disable it on the next `nmi` call and set @@ -75,4 +80,31 @@ @game: JAL Player::update .endproc + + .ifdef PAL + ;; All the code that is needed to fix some values for PAL machines. + .proc pal_handler + ;; Check if 5 frames have passed since last counter reset. + lda Driver::zp_pal_counter + cmp #4 + beq @do_handle + + ;; Nope! Reset the player's step on PAL and increase the counter. + lda #1 + sta Player::zp_step_on_pal + inc Driver::zp_pal_counter + bne @end + + @do_handle: + ;; Increase the step just for this frame and reset the counter. + lda Player::zp_step_on_pal + clc + adc #2 + sta Player::zp_step_on_pal + lda #0 + sta Driver::zp_pal_counter + @end: + rts + .endproc + .endif .endscope diff --git a/src/jetpac.s b/src/jetpac.s index 184374e..65b5d11 100644 --- a/src/jetpac.s +++ b/src/jetpac.s @@ -52,6 +52,12 @@ ;; Initialize the assets for the game. jsr Assets::init + ;; Initialize some PAL-specific constants. + .ifdef PAL + lda #0 + sta Driver::zp_pal_counter + .endif + ;; We shadow the PPU control register in memory. Depending on the `make` ;; target we might need to switch directly to the main game. Otherwise we go ;; into the title as expected. diff --git a/src/player.s b/src/player.s index 55245f6..9cb73f3 100644 --- a/src/player.s +++ b/src/player.s @@ -100,6 +100,14 @@ ;; Simple counter for the walking animation. zp_walk_counter = $51 + .ifdef PAL + ;; The increment/decrement to be applied to the velocity on a PAL + ;; system. This value is updated on `driver.s` on each frame. + ;; + ;; NOTE: only used on PAL. + zp_step_on_pal = $52 + .endif + ;; How many animations are there for walking? WALK_ANIMATION_NR = 3 @@ -113,6 +121,12 @@ lda #%01000100 sta zp_state + ;; Set the step to be applied on PAL. + .ifdef PAL + lda #1 + sta zp_step_on_pal + .endif + ;; Reset velocity and walking counter. lda #0 sta zp_target_velocity_y @@ -236,13 +250,27 @@ sbc Globals::zp_tmp0 beq @apply_velocity - ;; Increase or decrease depending on what we have now. - ;; TODO: inc/dec might not quite cut it in NTSC vs PAL + ;; Increase or decrease depending on what we have now. Note that how + ;; this is done depends on whether we are on NTSC or PAL. bmi @down - dec zp_velocity_y + .ifdef PAL + lda zp_velocity_y + sec + sbc zp_step_on_pal + sta zp_velocity_y + .else + dec zp_velocity_y + .endif jmp @apply_velocity @down: - inc zp_velocity_y + .ifdef PAL + lda zp_velocity_y + clc + adc zp_step_on_pal + sta zp_velocity_y + .else + inc zp_velocity_y + .endif jmp @apply_velocity @blast_off: @@ -334,17 +362,30 @@ ;; and we just subtract the current velocity and see if we either have ;; to accelerate or decelerate to reach that, and we do that with steps. @apply_acceleration: - ;; TODO: as with vertical motion, mind NTSC vs PAL sta Globals::zp_tmp0 lda zp_velocity_x sec sbc Globals::zp_tmp0 beq @apply_velocity bmi @accelerate_left - dec zp_velocity_x + .ifdef PAL + lda zp_velocity_x + sec + sbc zp_step_on_pal + sta zp_velocity_x + .else + dec zp_velocity_x + .endif jmp @apply_velocity @accelerate_left: - inc zp_velocity_x + .ifdef PAL + lda zp_velocity_x + clc + adc zp_step_on_pal + sta zp_velocity_x + .else + inc zp_velocity_x + .endif ;; With the final velocity already at hand, update the position with it. @apply_velocity: diff --git a/src/vectors.s b/src/vectors.s index f4c515c..f9aa31d 100644 --- a/src/vectors.s +++ b/src/vectors.s @@ -85,6 +85,11 @@ lda #$02 sta OAM::DMA + ;; PAL-specific code + .ifdef PAL + jsr Driver::pal_handler + .endif + ;; TODO: some actions here will depend on the status of the game... ;; Decrease title timer. |