Optimize object displays and preload map scrolling to stay in VBlank

8 files changed, 190 insertions, 110 deletions

diff --git a/definitions.gbasm b/definitions.gbasm
index 18b4237..84e7691 100644
--- a/definitions.gbasm
+++ b/definitions.gbasm
@@ -27,6 +27,13 @@
 .DEFINE mem_map_loading_flags ($c00c)
 ; bit 0: if the object should be reloaded (scroll or first load)
 ; bit 1: if the interactions should be checked (at the end of a movement)
+; bit 2: if the prepared block should be updated at the next frame
+
+.DEFINE mem_prepared_block_tile ($c00d)
+.DEFINE mem_prepared_block_position_1 ($c00e)
+.DEFINE mem_prepared_block_position_2 ($c00f)
+
+.DEFINE mem_object_load_counter ($c010)
 
 .DEFINE next_free_head_higher_bytes $c7
 .DEFINE mem_next_free_head_lower_bytes ($c6ff)
diff --git a/main.gbasm b/main.gbasm
index f96b893..ad1fa44 100644
--- a/main.gbasm
+++ b/main.gbasm
@@ -10,6 +10,7 @@ New_Dungeon:
 	CALL =Initialize_Objects
 	CALL =Load_Tile
 	CALL =Load_Map
+	CALL =Load_Objects
 
 	; LCDC
 	LD A, $87
@@ -21,8 +22,8 @@ New_Dungeon:
 	JP =Wait_for_VRAM.loop
 
 VBLANK_Entrypoint:
-	CALL =Display_Scrolling_Map
-	CALL =Display_Objects
+	CALL =Display_Prepared_Block
+	CALL =Display_Object
 	CALL =Display_Entities
 
 	CALL =Object_Interactions_Check
@@ -30,6 +31,7 @@ VBLANK_Entrypoint:
 	CALL =Pad_Button_Check
 	CALL =Move_Bunny
 
+	CALL =Prepare_Scrolling_Map
 	RET
 
 .INCLUDE "tiles.gbasm"
diff --git a/map/loading.gbasm b/map/loading.gbasm
index e42f388..be4c8a4 100644
--- a/map/loading.gbasm
+++ b/map/loading.gbasm
@@ -13,6 +13,7 @@ Load_Map:
 		Load_Map.For_X:
 			LD A, C
 			CALL =Load_Block
+			CALL =Display_Prepared_Block
 
 			INC C
 			LD A, C
@@ -98,7 +99,7 @@ Load_Column: ; (+1/-1 direction in B)
 	POP AF
 	RET
 
-Display_Scrolling_Map:
+Prepare_Scrolling_Map:
 	LD A, $mem_map_loading_flags
 	BIT 0, A
 	JR Z, =Display_Scrolling_Map.End
@@ -211,59 +212,33 @@ Load_Block: ; X in A, Y in B
 	ADD $20
 	LD C, A
 
+	LD A, $mem_map_loading_flags
+	SET 2, A
+	LD $mem_map_loading_flags, A
+
+
 	POP DE
+
+	LD A, D
+	LD $mem_prepared_block_position_1, A
+	LD A, E
+	LD $mem_prepared_block_position_2, A
+
 	POP AF
 
 	CALL =Is_Solid
-
 	CP $00
+
 	JR Z, =Load_Block.Empty
 	Load_Block.Solid:
 		LD A, C
-	CALL =VBlank_Wait
-		LD (DE), A
-		LD A, E
-		OR $20
-		LD E, A
-		LD A, C
-		OR $02
-	CALL =VBlank_Wait
-		LD (DE), A
-		INC E
-		LD A, C
-		OR $03
-	CALL =VBlank_Wait
-		LD (DE), A
-		LD A, E
-		AND $DF
-		LD E, A
-		LD A, C
-		OR $01
-	CALL =VBlank_Wait
-		LD (DE), A
+		LD $mem_prepared_block_tile, A
 
 		JR =Load_Block.End
 
 	Load_Block.Empty:
 		LD A, $00
-	CALL =VBlank_Wait
-		LD (DE), A
-		LD A, E
-		OR $20
-		LD E, A
-		LD A, $00
-	CALL =VBlank_Wait
-		LD (DE), A
-		INC E
-		LD A, $00
-	CALL =VBlank_Wait
-		LD (DE), A
-		LD A, E
-		AND $DF
-		LD E, A
-		LD A, $00
-	CALL =VBlank_Wait
-		LD (DE), A
+		LD $mem_prepared_block_tile, A
 
 	Load_Block.End:
 
@@ -272,6 +247,53 @@ Load_Block: ; X in A, Y in B
 	POP BC
 	RET
 
+Display_Prepared_Block:
+	PUSH AF
+	PUSH BC
+	PUSH DE
+
+	LD A, $mem_map_loading_flags
+	BIT 2, A
+	JR Z, =Display_Prepared_Block.End
+
+	LD A, $mem_map_loading_flags
+	RES 2, A
+	LD $mem_map_loading_flags, A
+
+	LD A, $mem_prepared_block_position_1
+	LD D, A
+
+	LD A, $mem_prepared_block_position_2
+	LD E, A
+
+	LD A, $mem_prepared_block_tile
+	LD C, A
+
+	LD (DE), A
+	LD A, E
+	OR $20
+	LD E, A
+	LD A, C
+	OR $02
+	LD (DE), A
+	INC E
+	LD A, C
+	OR $03
+	LD (DE), A
+	LD A, E
+	AND $DF
+	LD E, A
+	LD A, C
+	OR $01
+	LD (DE), A
+
+	Display_Prepared_Block.End:
+
+	POP DE
+	POP BC
+	POP AF
+	RET
+
 Is_Solid: ; X in A, Y in B, Result A
 	PUSH BC
 
diff --git a/map/objects.gbasm b/map/objects.gbasm
index bfaa903..22a65ee 100644
--- a/map/objects.gbasm
+++ b/map/objects.gbasm
@@ -3,6 +3,10 @@ Initialize_Objects:
 	OR $01
 	LD $mem_map_loading_flags, A
 	LD HL, $mem_object_list
+	CALL =Spawn_stairs
+	RET
+
+Spawn_stairs:
 	LD A, $60
 	LD (HL+), A
 	
@@ -42,6 +46,9 @@ Initialize_Objects:
 	LD (HL+), A
 	LD A, C
 	LD (HL+), A
+	INC HL
+	INC HL
+	INC HL
 	RET
 
 Stairs_action:
@@ -57,88 +64,109 @@ Stairs_action:
 
 	JP =New_Dungeon
 
-Display_Objects:
-	LD A, $mem_map_loading_flags
-	BIT 0, A
-	JR Z, =Display_Objects.End
-	LD A, $mem_moving_animation_step
-	CP $00
-	JR NZ, =Display_Objects.End
+Display_Object:
 	LD HL, $mem_object_list
 	Display_Objects.loop:
-		LD A, (HL+)
-		CP $00
-		JR Z, =Display_Objects.next
-		LD C, A
-		LD A, (HL+)
-		ADD $80
-		LD D, A
-		LD A, $mem_viewport_x
-		SUB $83
-		CP D
-		JR NC, =Display_Objects.next
-		ADD $10
-		CP D
-		JR C, =Display_Objects.next
-		LD A, D
-		SUB $80
-		LD D, A
+	LD A, $mem_object_load_counter
+	INC A
+	AND $0f
+	LD $mem_object_load_counter, A
+	SLA A
+	SLA A
+	SLA A
+	AND $f8
+	LD L, A
 
-		LD A, (HL+)
-		ADD $80
-		LD B, A
-		LD A, $mem_viewport_y
-		SUB $83
-		CP B
-		JR NC, =Display_Objects.next
-		ADD $10
-		CP B
-		JR C, =Display_Objects.next
-		LD A, B
-		SUB $80
-		LD B, A
+	LD A, (HL+)
+	LD C, A
+	LD A, (HL+)
+	ADD $80
+	LD D, A
+	LD A, $mem_viewport_x
+	SUB $83
+	CP D
+	JR NC, =Display_Objects.End
+	ADD $10
+	CP D
+	JR C, =Display_Objects.End
+	LD A, D
+	SUB $80
+	LD D, A
 
-		LD A, D
-		CALL =Construct_Tile_Address
+	LD A, (HL+)
+	ADD $80
+	LD B, A
+	LD A, $mem_viewport_y
+	SUB $83
+	CP B
+	JR NC, =Display_Objects.End
+	ADD $10
+	CP B
+	JR C, =Display_Objects.End
+	LD A, B
+	SUB $80
+	LD B, A
 
-		CALL =VBlank_Wait
-		LD A, C
-		LD (DE), A
+	LD A, C
+	CP $00
 
-		INC E
-		INC C
+	JR Z, =Display_Objects.Nothing
 
-		CALL =VBlank_Wait
-		LD A, C
-		LD (DE), A
+	LD A, D
+	CALL =Construct_Tile_Address
 
-		INC C
+	LD A, C
+	LD (DE), A
 
-		LD A, E
-		XOR $21
-		LD E, A
+	INC E
+	INC C
 
-		CALL =VBlank_Wait
-		LD A, C
-		LD (DE), A
+	LD A, C
+	LD (DE), A
 
-		INC C
-		INC E
+	INC C
 
-		CALL =VBlank_Wait
-		LD A, C
-		LD (DE), A
+	LD A, E
+	XOR $21
+	LD E, A
+
+	LD A, C
+	LD (DE), A
+
+	INC C
+	INC E
+
+	LD A, C
+	LD (DE), A
 
-		Display_Objects.next:
-		LD A, L
-		AND $f8
-		ADD $08
-		LD L, A
-		CP $80
-		JR NZ, =Display_Objects.loop
 	Display_Objects.End:
 	RET
 
+	Display_Objects.Nothing:
+	LD A, D
+	CALL =Load_Block
+	CALL =Display_Prepared_Block
+	RET
+
+Load_Objects:
+	CALL =Display_Object
+	CALL =Display_Object
+	CALL =Display_Object
+	CALL =Display_Object
+	CALL =Display_Object
+	CALL =Display_Object
+	CALL =Display_Object
+	CALL =Display_Object
+	CALL =Display_Object
+	CALL =Display_Object
+	CALL =Display_Object
+	CALL =Display_Object
+	CALL =Display_Object
+	CALL =Display_Object
+	CALL =Display_Object
+	CALL =Display_Object
+	RET
+
 Object_Interactions_Check:
 	LD A, $mem_map_loading_flags
 	BIT 1, A
@@ -166,8 +194,21 @@ Object_Interactions_Check:
 		LD A, (HL+)
 		LD E, A
 
+		PUSH BC
+
+		; So we have HL set to the object pointer
+		LD A, L
+		AND $f8
+		LD L, A
+
+		; This is confusing but this thing is actually CALL DE
+		LD BC, =Object_Interactions_Check.interaction_end
+		PUSH BC
 		PUSH DE
 		RET
+		Object_Interactions_Check.interaction_end:
+
+		POP BC
 
 		Object_Interactions_Check.next:
 		LD A, L
diff --git a/scripts/generate-tiledata.py b/scripts/generate-tiledata.py
index ff62b0e..25c79ce 100644
--- a/scripts/generate-tiledata.py
+++ b/scripts/generate-tiledata.py
@@ -16,6 +16,8 @@ print("\n\t; Trees")
 get_sprite_png_parse_output("./sprites/bg/tree-tileset.png")
 print("\n\t; Stairs")
 get_sprite_png_parse_output("./sprites/bg/stairs.png")
+print("\n\t; Carrot")
+get_sprite_png_parse_output("./sprites/bg/carrot.png")
 
 sprite_idx = 0x02
 print("\nOBJ_Tile_Image_Data:")
diff --git a/sprites/bg/carrot.png b/sprites/bg/carrot.png
new file mode 100644
index 0000000..1c42ba9
--- /dev/null
+++ b/sprites/bg/carrot.png
diff --git a/tiles.gbasm b/tiles.gbasm
index 48cb285..6c902d4 100644
--- a/tiles.gbasm
+++ b/tiles.gbasm
@@ -24,7 +24,7 @@ Load_Tile:
 	CALL =Load_Number_Font
 	LD HL, $9200
 	LD DE, =BG_Tile_Image_Data
-	LD BC, $0440
+	LD BC, $0480
 	CALL =memcpy
 	RET
 
diff --git a/tileset.gbasm b/tileset.gbasm
index 39a32db..854e33e 100644
--- a/tileset.gbasm
+++ b/tileset.gbasm
@@ -72,6 +72,12 @@ BG_Tile_Image_Data:
 	.DB $9f, $91, $ff, $91, $ff, $91, $ff, $91, $ff, $91, $fd, $93, $f1, $9f, $ff, $ff ; 0x62
 	.DB $ff, $11, $ff, $11, $ff, $11, $f1, $1f, $91, $7f, $11, $ff, $11, $ff, $ff, $ff ; 0x63
 
+	; Carrot
+	.DB $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $02, $02, $07, $05, $0f, $08 ; 0x64
+	.DB $00, $00, $30, $30, $58, $68, $b4, $fc, $fe, $aa, $ac, $f4, $58, $b8, $a0, $e0 ; 0x65
+	.DB $1f, $10, $1f, $10, $3e, $21, $3c, $23, $7b, $47, $7c, $4c, $70, $70, $00, $00 ; 0x66
+	.DB $c0, $40, $a0, $60, $20, $e0, $c0, $c0, $00, $00, $00, $00, $00, $00, $00, $00 ; 0x67
+
 OBJ_Tile_Image_Data:
 
 	; Bunny side