Begin work on title screen

.gitignore

@@ -1,6 +1,8 @@
 *.o
 *.2bpp
+*.tilemap
 is.gb
 is.gb.sym
 png/map/*.s
 png/map/*.inc
+dev clips/

Makefile

@@ -2,7 +2,7 @@ PYTHON ?= python
 
 # Graphics
 SPRITE_PNG := $(shell find png/sprite -type f -name '*.png')
-
+BG_PNG     := $(shell find png/bg -type f -name '*.png')
 MAP_PNG    := $(shell find png/map -type f -name '*.png' -not -name '*_coll.png')
 MAP_COLL   := $(shell find png/map -type f -name '*_coll.png')
 
@@ -10,6 +10,7 @@ MAP_COLL   := $(shell find png/map -type f -name '*_coll.png')
 MAP_S	    := $(MAP_PNG:%.png=%.s)
 MAP_INC     := $(MAP_PNG:%.png=%.inc)
 SPRITE_2BPP := $(SPRITE_PNG:%.png=%.2bpp)
+BG_DATA     := $(BG_PNG:%.png=%.2bpp) $(BG_PNG:%.png=%.tilemap)
 
 # Code
 SFILES := $(shell find src -type f -name '*.s')
@@ -24,6 +25,7 @@ is.gb is.gb.sym: $(OFILES)
 
 $(OFILES): $(MAP_INC)
 $(OFILES): $(SPRITE_2BPP)
+$(OFILES): $(BG_DATA)
 
 %.o: %.s
 	@echo "[ASSEMBLE] $<"
@@ -37,6 +39,10 @@ png/sprite/%.2bpp: png/sprite/%.png
 	@echo "[SPRITE]   $<"
 	@rgbgfx -o $@ $<
 
+png/bg/%.2bpp png/bg/%.tilemap: png/bg/%.png
+	@echo "[BG]       $<"
+	@rgbgfx -T -u -o "$(shell dirname $<)/$(shell basename --suffix=.png $<).2bpp" $<
+
 clean:
-	@rm -f is.gb is.gb.sym $(OFILES) $(MAP_S) $(MAP_INC) $(SPRITE_2BPP)
+	@rm -f is.gb is.gb.sym $(OFILES) $(MAP_S) $(MAP_INC) $(SPRITE_2BPP) $(BG_DATA)
 	@echo "All build files removed"

inc/game.inc

@@ -0,0 +1,2 @@
+DEF GAME_STATEF_TITLE EQU (1 << 0)
+DEF GAME_STATEF_GAME EQU (1 << 1)

src/game.s

@@ -0,0 +1,25 @@
+SECTION "Game Loop", ROM0
+
+Game_Start::
+    ld hl, intro_Data
+    call Map_Load
+
+    call Player_Init
+
+.loop:
+    ld hl, frame
+    inc [hl]
+
+    call Keys_Update
+    call Player_Update
+
+    ; wait for vblank
+    halt
+
+    call Map_Update
+
+    ; ~160 cycles
+    ld a, HIGH(_OAM)
+    call DMA_Start
+
+    jr .loop

src/main.s

@@ -1,3 +1,4 @@
+INCLUDE "game.inc"
 INCLUDE "hardware.inc"
 INCLUDE "util.inc"
 
@@ -11,9 +12,10 @@ rept $150 - _entry
     db 0
 endr
 
-SECTION "Frame", WRAM0
+SECTION "Game State", WRAM0
 
 frame:: db
+state:: db
 
 SECTION "VBlank", ROM0[$40]
 
@@ -23,19 +25,17 @@ handle_vblank:
 SECTION "Code", ROM0
 
 start:
+    ; init/disable lcd
     ld hl, rLCDC
     res 7, [hl]
     res 2, [hl]
 
+    ; enable vblank
     ld hl, rIE
     ld [hl], IEF_VBLANK
 
-    ld hl, intro_Data
-    call Map_Load
-
     call OAM_Init
     call Keys_Init
-    call Player_Init
 
     ; set palette
     ld a, %11100100
@@ -44,26 +44,18 @@ start:
     ld hl, rBGP
     ld [hl], a
 
-    ; enable lcd, sprites and interrupts
-    ld hl, rLCDC
-    set 7, [hl]
-    set 1, [hl]
-    ei
+    ld a, GAME_STATEF_TITLE
+    ld [state], a
 
 .loop:
-    ld hl, frame
-    inc [hl]
-
-    call Keys_Update
-    call Player_Update
-
-    ; wait for vblank
-    halt
-
-    call Map_Update
+    ld a, [state]
+    cp GAME_STATEF_TITLE
+    jr nz, .check_game_state
 
-    ; ~160 cycles
-    ld a, HIGH(_OAM)
-    call DMA_Start
+    call Title_Start
+    jr .loop
 
-    jp .loop
+    ; only two states atm, no need to check anything yet
+.check_game_state:
+    call Game_Start
+    jr .loop

src/title.s

@@ -0,0 +1,44 @@
+INCLUDE "hardware.inc"
+
+SECTION "Title Loop", ROM0
+
+titleTiles: INCBIN "png/bg/title.2bpp"
+titleMap: INCBIN "png/bg/title.tilemap"
+titleMapEnd:
+
+DEF TITLE_TILES_SIZE EQUS "titleMap - titleTiles"
+DEF TITLE_MAP_SIZE EQUS "titleMapEnd - titleMap"
+
+Title_Start::
+    ; load title screen
+    ld bc, _VRAM
+    ld hl, titleTiles
+    ld de, TITLE_TILES_SIZE
+    call memcpy16
+
+    ; could probably be sped up...
+    FOR Y, 18
+        ld bc, _SCRN0 + 32 * Y
+        ld hl, titleMap + 20 * Y
+        ld d, 20
+        call memcpy
+    ENDR
+
+    ; enable lcd, sprites and interrupts
+    ld hl, rLCDC
+    set 7, [hl]
+    set 1, [hl]
+    ei
+
+.loop:
+    ld hl, frame
+    inc [hl]
+
+    call Keys_Update
+
+    ; todo: check for start press and transition to game state
+
+    ; wait for vblank
+    halt
+
+    jr .loop

src/util.s

@@ -21,6 +21,24 @@ memcpy::
     jr nz, memcpy ; 12/8
     ret ; 16
 
+; Copy data between two regions (takes TODO cycles). Only use when size > 255
+; @param bc Pointer to the destination region
+; @param hl Pointer to the source region
+; @param de Size (in bytes) to copy. Must be >0
+; @destroy a, b, c, d, e, h, l
+memcpy16::
+    ld a, [hli] ; 8
+    ld [bc], a ; 8
+    inc bc ; 8
+
+    dec de ; 8
+    xor a  ; 4
+    or d   ; 4
+    or e   ; 4
+
+    jr nz, memcpy16 ; 12/8
+    ret ; 16
+
 ; Fill a memory region with a value
 ; @param hl Pointer to the destination region
 ; @param a  Byte to fill with