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-rw-r--r--include/globals.s6
-rw-r--r--include/ppu.s4
-rw-r--r--src/assets.s56
-rw-r--r--src/driver.s26
-rw-r--r--src/jetpac.s9
-rw-r--r--src/vectors.s4
6 files changed, 92 insertions, 13 deletions
diff --git a/include/globals.s b/include/globals.s
index f4e4861..35665f7 100644
--- a/include/globals.s
+++ b/include/globals.s
@@ -1,8 +1,7 @@
;; Global variables used throughout the code base.
.scope Globals
;;;
- ;; Argument values as defined in https://github.com/mssola/style.nes. Note
- ;; that these variables can also be used as temporary variables.
+ ;; Argument values reserved passing arguments to functions in memory.
zp_arg0 = $00
zp_arg1 = $01
zp_arg2 = $02
@@ -30,7 +29,8 @@
;; |-----+------------+-------------------------------------------------------------|
;; | 7 | render | Game logic is over, block main code until NMI code is over. |
;; | 6 | ppu | PPU registers have to be touched |
- ;; | 5-2 | - | Unused |
+ ;; | 5-3 | - | Unused |
+ ;; | 2 | title over | We are transitioning from title to game |
;; | 1-0 | game | 0: title; 1: game; 2: game over, 3: game over (coin) |
zp_flags = $20
.endscope
diff --git a/include/ppu.s b/include/ppu.s
index dd24422..a9c0ed2 100644
--- a/include/ppu.s
+++ b/include/ppu.s
@@ -9,4 +9,8 @@
;; Shadow for the PPU::CONTROL value. Touch this value instead of accessing
;; the PPU register directly.
zp_control = $80
+
+ ;; Shadow for the PPU::MASK value. Touch this value instead of accessing the
+ ;; PPU register directly.
+ zp_mask = $81
.endscope
diff --git a/src/assets.s b/src/assets.s
index 8e839d3..ffc6585 100644
--- a/src/assets.s
+++ b/src/assets.s
@@ -74,7 +74,30 @@
dex
bne @upper_title_bar_loop
- ;; TODO: store back palettes after game over.
+ ;; Update 2nd palette for background. This is redundant upon entering
+ ;; the game, but it makes sense after a game over.
+ lda #$3F
+ sta PPU::ADDRESS
+ lda #$09
+ sta PPU::ADDRESS
+ lda #$28
+ sta PPU::DATA
+ lda #$2C
+ sta PPU::DATA
+ lda #$16
+ sta PPU::DATA
+
+ ;; Update 1st palette for foreground.
+ lda #$3F
+ sta PPU::ADDRESS
+ lda #$11
+ sta PPU::ADDRESS
+ lda #$30
+ sta PPU::DATA
+ lda #$10
+ sta PPU::DATA
+ lda #$30
+ sta PPU::DATA
rts
.endproc
@@ -82,11 +105,32 @@
;; Performs all the needed tricks in order to get the second nametable as
;; expected.
.proc prepare_for_main_screen
- ;; TODO: second palette for background should be:
- ;; .byte $0F, $14, $2C, $28
- ;;
- ;; TODO: first palette for the foreground should be:
- ;; .byte $0F, $16, $10, $30
+ bit PPU::STATUS
+
+ ;; Update 2nd palette for background.
+ lda #$3F
+ sta PPU::ADDRESS
+ lda #$09
+ sta PPU::ADDRESS
+ lda #$14
+ sta PPU::DATA
+ lda #$2C
+ sta PPU::DATA
+ lda #$28
+ sta PPU::DATA
+
+ ;; Update 1st palette for foreground.
+ lda #$3F
+ sta PPU::ADDRESS
+ lda #$11
+ sta PPU::ADDRESS
+ lda #$16
+ sta PPU::DATA
+ lda #$10
+ sta PPU::DATA
+ lda #$30
+ sta PPU::DATA
+
rts
.endproc
diff --git a/src/driver.s b/src/driver.s
index 8b7f8ce..bb0303f 100644
--- a/src/driver.s
+++ b/src/driver.s
@@ -9,7 +9,25 @@
zp_player_timer = $30
PLAYER_TIMER_VALUE = HZ * 2
+ ;; 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
+ ;; the `title over` flag. With that, call again this function so the
+ ;; switching is actually performed.
.proc switch
+ ;; Some things from here require the PPU to be disabled. Hence, if
+ ;; that's not the case, disable it now. The `ppu` and the `title over`
+ ;; flags are set as well.
+ lda PPU::zp_mask
+ beq @do_switch
+ lda #%01000100
+ ora Globals::zp_flags
+ sta Globals::zp_flags
+ lda #$00
+ sta PPU::zp_mask
+ rts
+
+ @do_switch:
;; Get the assets ready for the main screen. That is, make sure that the
;; palettes and such are as desired since the title screen needed
;; another setup.
@@ -19,6 +37,10 @@
lda #%10001010
sta PPU::zp_control
+ ;; Enable back the PPU.
+ lda #%00011110
+ sta PPU::zp_mask
+
;; Setup the player timer.
.ifdef PARTIAL
lda #1
@@ -28,10 +50,10 @@
sta zp_player_timer
;; Mark the state of the game as "game". That is, the player has
- ;; started. Also set the `ppu` flag so the PPU control update takes
- ;; place.
+ ;; started. Also set the `ppu` flag and unset the `title over` one.
lda #%01000001
ora Globals::zp_flags
+ and #%11111011
sta Globals::zp_flags
rts
diff --git a/src/jetpac.s b/src/jetpac.s
index 66d5457..184374e 100644
--- a/src/jetpac.s
+++ b/src/jetpac.s
@@ -40,8 +40,8 @@
.include "assets.s"
.include "background.s"
.include "player.s"
-.include "driver.s"
.include "title.s"
+.include "driver.s"
.include "vectors.s"
.proc main
@@ -72,6 +72,7 @@
;; Enable back the PPU
lda #%00011110
+ sta PPU::zp_mask
sta PPU::MASK
@main_game_loop:
@@ -85,9 +86,15 @@
jmp @over
@title_screen:
+ ;; If we are in a transitioning state, avoid the update from the title.
+ lda Globals::zp_flags
+ and #%00000100
+ bne @do_switch
+
jsr Title::update
beq @set_flags
+@do_switch:
;; Start was pressed by the player, switch to the main game.
jsr Driver::switch
jmp @set_flags
diff --git a/src/vectors.s b/src/vectors.s
index b06f404..b404d98 100644
--- a/src/vectors.s
+++ b/src/vectors.s
@@ -103,7 +103,9 @@
bit PPU::STATUS
- ;; Update the PPU control register with the shadowed value.
+ ;; Update the PPU control/mask registers with shadowed values.
+ lda PPU::zp_mask
+ sta PPU::MASK
lda PPU::zp_control
sta PPU::CONTROL