State game over only when all players are dead

This is a bit contrary to the original game, where each player would get
its own "Game over" event.

Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com>

4 files changed, 64 insertions, 21 deletions

diff --git a/src/driver.s b/src/driver.s
index 1ac5718..3bf4399 100644
--- a/src/driver.s
+++ b/src/driver.s
@@ -258,8 +258,9 @@
         lda Explosions::zp_active
         bne @sprite_cycling
 
-        ;; After all the explosions have been done, do we have any life left?
-        lda Player::zp_lifes
+        ;; After all the explosions have been done, is any player alive?
+        lda Globals::zp_multiplayer
+        and #%00000110
         bne @reset_timer
 
         ;; No! Toggle the game over bit.
diff --git a/src/jetpac.s b/src/jetpac.s
index e8d6543..4802e74 100644
--- a/src/jetpac.s
+++ b/src/jetpac.s
@@ -111,7 +111,7 @@
 .endproc
 
 .proc main
-    ;; TODO: score initialization has to happen here.
+    ;; TODO: high score initialization has to happen here.
 
 @init:
     ;; Disable the PPU and zero out variables which shadow PPU registers.
@@ -239,7 +239,7 @@
     bit Globals::zp_flags
     bmi @wait_for_render_over
 
-    ;; Did the user want to start over?
+    ;; Can the player start over?
     lda Globals::zp_tmp0
     beq @main_game_loop
     jmp @init
diff --git a/src/over.s b/src/over.s
index a2a0f9f..6d8ed8d 100644
--- a/src/over.s
+++ b/src/over.s
@@ -147,15 +147,13 @@
         rts
     .endproc
 
-    ;; Render the regular "Game over player X" screen.
-    ;;
-    ;; TODO: multiplayer support.
+    ;; Render the regular "Game over" screen.
     .proc render_regular_game_over
         ;; Set the position.
         bit PPU::m_status
         ldx #$29
         stx PPU::m_address
-        ldx #$67
+        ldx #$6C
         stx PPU::m_address
 
         ;; And just iterate over the "message" until we reach the end of string
@@ -186,11 +184,7 @@
     message:
         ;; "GAME "
         .byte $21, $1B, $27, $1F, $00
-        ;; "OVER "
-        .byte $29, $30, $1F, $2C, $00
-        ;; "PLAYER "
-        .byte $2A, $26, $1B, $33, $1F, $2C, $00
-        ;; "1"
-        .byte $11, $FF
+        ;; "OVER"
+        .byte $29, $30, $1F, $2C, $FF
     .endproc
 .endscope
diff --git a/src/player.s b/src/player.s
index 7e215a5..53695b4 100644
--- a/src/player.s
+++ b/src/player.s
@@ -834,13 +834,25 @@
 
     ;; That's just german for "the Bart, the".
     .proc die_bart_die
-        ;; Decrement the life. If we reach zero, then there's no point on
-        ;; signaling the NMI code to render this change.
-        ;;
-        ;; TODO: this is just considering the first player only!.
-        dec Player::zp_lifes
-        beq @skip_life_update
-
+        ;; Decrement the life.
+        lda Globals::zp_multiplayer
+        and #$01
+        tax
+        dec Player::zp_lifes, x
+        bne @nmi_update
+
+        ;; If this poor guy is over, then mark it in the multiplayer bitmap.
+        cpx #0
+        bne @player_2_over
+        lda #%11111101
+        bne @set_multi
+    @player_2_over:
+        lda #%11111011
+    @set_multi:
+        and Globals::zp_multiplayer
+        sta Globals::zp_multiplayer
+
+    @nmi_update:
         ;; Notify NMI code to render lifes again, as they have changed.
         lda Player::zp_state
         ora #%00001000
@@ -862,6 +874,9 @@
         ora Globals::zp_flags
         sta Globals::zp_flags
 
+        ;; Try to switch the player.
+        jsr Player::try_player_switch
+
         ;; Create an explosion.
         lda Player::zp_screen_y
         sta Globals::zp_arg2
@@ -869,4 +884,37 @@
         sta Globals::zp_arg3
         JAL Explosions::create
     .endproc
+
+    ;; Try to switch the active player if we are in multiplayer.
+    .proc try_player_switch
+        ;; If multiplayer is not enabled, don't even bother.
+        bit Globals::zp_multiplayer
+        bpl @end
+
+        lda Globals::zp_multiplayer
+        tax
+        and #$01
+        beq @try_player_2
+
+        ;; Switch to player 1 if it's still alive.
+        txa
+        and #$02
+        beq @end
+        txa
+        and #$FE
+        bne @set_and_end
+
+    @try_player_2:
+        ;; Switch to player 2 if it's still alive.
+        txa
+        and #$04
+        beq @end
+        txa
+        ora #$01
+
+    @set_and_end:
+        sta Globals::zp_multiplayer
+    @end:
+        rts
+    .endproc
 .endscope