Add per entity spawning rate

4 files changed, 158 insertions, 23 deletions

diff --git a/entity/bunny.gbasm b/entity/bunny.gbasm
index 7789ec5..4ae93f3 100644
--- a/entity/bunny.gbasm
+++ b/entity/bunny.gbasm
@@ -296,7 +296,7 @@ Move_Bunny:
 		INC A
 		DAA
 		JR C, =.End_movement.skip_mana_regen
-		CP $30
+		CP $31
 		JR NC, =.End_movement.skip_mana_regen
 		LD $mem_bunny_mana, A
 
diff --git a/entity/init.gbasm b/entity/init.gbasm
index 4351265..09ca315 100644
--- a/entity/init.gbasm
+++ b/entity/init.gbasm
@@ -128,12 +128,9 @@ Fix_Bunny_screen:
 	RET
 
 Initialize_Enemy: ; HL => pointer to entity struct
-	LD A, $mem_enemies_alive_count
-	INC A
-	LD $mem_enemies_alive_count, A
-
-	CALL =RNG_Step
-	AND $03
+	CALL =Enemy_idx_to_spawn
+	CP $ff
+	RET Z
 	ADD $03
 
 Initialize_Entity: ; HL => pointer to entity struct, A => entity loaded index, 1 in $tmp_var_3 if should retry if collsion (could potentially fail multiple time/infinite loop)
@@ -241,21 +238,10 @@ Initialize_Entity: ; HL => pointer to entity struct, A => entity loaded index, 1
 	LD A, $03
 	LD (HL+), A
 
-	LD BC, =Entity_list
-	LD D, high($mem_loaded_entities_indices)
-	LD A, low($mem_loaded_entities_indices)
-	ADD E
-	LD E, A
-	LD A, (DE)
-	SLA A
-	SLA A
-	SLA A
-	ADD $02
-	ADD low(=Entity_list)
-	LD C, A
-	LD A, high(=Entity_list)
-	ADC $00
-	LD B, A
+	LD A, E
+	CALL =Entity_idx_to_entity_list_ptr
+	INC BC
+	INC BC
 
 	; Turn
 	LD A, (BC)
@@ -292,6 +278,16 @@ Initialize_Entity: ; HL => pointer to entity struct, A => entity loaded index, 1
 	ADD $06
 	LD L, A
 
+	LD A, E
+	CP $03
+	RET C
+
+	CP $07
+	RET NC
+
+	LD A, $mem_enemies_alive_count
+	INC A
+	LD $mem_enemies_alive_count, A
 	RET
 
 FindFreeEntity:
@@ -325,7 +321,7 @@ Respawn_Entities:
 	LD $tmp_var_3, A
 
 	CALL =RNG_Step
-	AND $0f
+	AND $07
 	CP $00
 	RET NZ
 
@@ -333,3 +329,95 @@ Respawn_Entities:
 
 	CALL =Initialize_Enemy
 	RET
+
+Enemy_spawn_pattern_to_probability: ; (1/(x + 1))
+	.DB 0b11111111
+	.DB 0b00000111
+	.DB 0b00000001
+	.DB 0b00000000
+
+Enemy_idx_to_spawn: ; Return in A, ff if no entity to be spawned
+	PUSH BC
+
+	LD A, $mem_entity_spawning_pattern
+	LD B, A
+
+	CALL =RNG_Step
+	AND $03
+	LD C, A
+	SLA A
+	CALL =RRx
+	LD A, B
+	AND $03
+
+	PUSH DE
+	LD DE, =Enemy_spawn_pattern_to_probability
+	ADD E
+	LD E, A
+	LD A, D
+	ADC $00
+	LD D, A
+	LD A, (DE)
+	POP DE
+
+	LD B, A
+	CALL =RNG_Step
+	AND B
+	CP $00
+	LD A, $ff
+	JR NZ, =.skip_set_enemy_idx
+
+	LD A, C
+
+	.skip_set_enemy_idx:
+
+	POP BC
+	RET
+
+.MACRODEF GET_ENTITY_IDX_SPAWN_RATE idx ; breaks BC & A
+	LD A, low($idx)
+	CALL =Entity_idx_to_entity_list_ptr
+	LD A, C
+	ADD $07
+	LD C, A
+	LD A, B
+	ADC $00
+	LD B, A
+	LD A, (BC)
+	AND $03
+.END
+
+Update_Enemies_Spawning_Pattern:
+	PUSH AF
+	PUSH BC
+	PUSH DE
+
+	LD E, $00
+	.GET_ENTITY_IDX_SPAWN_RATE $06
+	OR E
+	LD E, A
+
+	SLA E
+	SLA E
+	.GET_ENTITY_IDX_SPAWN_RATE $05
+	OR E
+	LD E, A
+
+	SLA E
+	SLA E
+	.GET_ENTITY_IDX_SPAWN_RATE $04
+	OR E
+	LD E, A
+
+	SLA E
+	SLA E
+	.GET_ENTITY_IDX_SPAWN_RATE $03
+	OR E
+
+	LD $mem_entity_spawning_pattern, A
+	DBG
+
+	POP DE
+	POP BC
+	POP AF
+	RET
diff --git a/entity/list.gbasm b/entity/list.gbasm
index 5aa71bd..0e2ba86 100644
--- a/entity/list.gbasm
+++ b/entity/list.gbasm
@@ -18,6 +18,9 @@ Entity_list:
 		; Starting mana
 		.DB $05
 
+		; Spawning rate (2 lsb)
+		.DB 0b11
+
 		.PADTO =.Fox+8
 
 	.Frog:
@@ -39,6 +42,9 @@ Entity_list:
 		; Starting mana
 		.DB $00
 
+		; Spawning rate (2 lsb)
+		.DB 0b01
+
 		.PADTO =.Frog+8
 
 	.Cat:
@@ -60,6 +66,9 @@ Entity_list:
 		; Starting mana
 		.DB $00
 
+		; Spawning rate (2 lsb)
+		.DB 0b11
+
 		.PADTO =.Cat+8
 
 	.Penguin:
@@ -81,6 +90,9 @@ Entity_list:
 		; Starting mana
 		.DB $05
 
+		; Spawning rate (2 lsb)
+		.DB 0b01
+
 		.PADTO =.Penguin+8
 
 	.Mouse:
@@ -102,6 +114,9 @@ Entity_list:
 		; Starting mana
 		.DB $00
 
+		; Spawning rate (2 lsb)
+		.DB 0b10
+
 		.PADTO =.Mouse+8
 
 	.Fimsh:
@@ -123,6 +138,9 @@ Entity_list:
 		; Starting mana
 		.DB $00
 
+		; Spawning rate (2 lsb)
+		.DB 0b00
+
 		.PADTO =.Fimsh+8
 
 	.QuestGoalBunny:
@@ -144,4 +162,7 @@ Entity_list:
 		; Starting mana
 		.DB $00
 
+		; Spawning rate (2 lsb)
+		.DB 0b00
+
 		.PADTO =.QuestGoalBunny+8
diff --git a/entity/utils.gbasm b/entity/utils.gbasm
index 8a44d6d..8394f9f 100644
--- a/entity/utils.gbasm
+++ b/entity/utils.gbasm
@@ -80,3 +80,29 @@ Get_Position_After_Move: ; entity (whatever alignement) in HL, direction to test
 	POP DE
 	POP HL
 	RET
+
+Entity_idx_to_entity_list_ptr: ; loaded idx in A, return in BC
+	PUSH DE
+
+	LD D, high($mem_loaded_entities_indices)
+	LD E, low($mem_loaded_entities_indices)
+	ADD E
+	LD E, A
+	LD A, (DE)
+	LD C, A
+	LD B, $00
+	SLA C
+	RL B
+	SLA C
+	RL B
+	SLA C
+	RL B
+	LD A, C
+	ADD low(=Entity_list)
+	LD C, A
+	LD A, B
+	ADC high(=Entity_list)
+	LD B, A
+
+	POP DE
+	RET