asar 1.90
lorom
dpbase 0
optimize dp always
optimize address ram


;;; RAM Variables
samus_collected_items = $7E09A4

samus_pos_x = $7E0AF6
samus_pos_x_sub = $7E0AF8
samus_pos_y = $7E0AFA
samus_pos_y_sub = $7E0AFC

enemy_index = $7E0E54

enemies_pos_x = $7E0F7A
enemies_pos_x_sub = $7E0F7C
enemies_pos_y = $7E0F7E
enemies_pos_y_sub = $7E0F80

enemies_flags1 = $7E0F86
enemies_flags2 = $7E0F88

enemies_spritemap = $7E0F8E
enemies_timer = $7E0F90
enemies_instruction_list = $7E0F92
enemies_instruction_timer = $7E0F94

enemies_ai_var0 = $7E0FA8
enemies_ai_var1 = $7E0FAA
enemies_ai_var2 = $7E0FAC
enemies_ai_var3 = $7E0FAE
enemies_ai_var4 = $7E0FB0
enemies_ai_var5 = $7E0FB2
enemies_parameter1 = $7E0FB4
enemies_parameter2 = $7E0FB6

ram_hdma_buffer = $7E9100


;;; Common enemy bank routines/constants
!enemy_empty_spritemap = $804D


;;; External routines
snd_playLib2Sfx = $8090CB  ; $90CB: Queue sound, sound library 2, max queued sounds allowed = 6
hdma_spawnEyeHdma = $88E8D9  ; $E8D9: Spawn morph ball eye beam HDMA object
ai_util_isSamusWithinYRadius = $A0AEED  ; $AEED: Is Samus within [A] pixel rows of enemy
ai_util_isSamusWithinXRadius = $A0AF0B  ; $AF0B: Is Samus within [A] pixel columns of enemy
ai_util_atan2 = $A0C0AE  ; $C0AE: Calculate angle of ([$12], [$14]) offset


;;; Variable aliases
; Read by beam HDMA object, TODO purpose unknown
eye_vars_hdma_flag = enemies_ai_var2
; Read by beam HDMA object
eye_vars_angle = enemies_ai_var3
; Used to add a delay during the opening/closing AI states
eye_vars_anim_delay = enemies_ai_var4
; Pointer to current AI state handler, called from pre-instruction
eye_vars_state = enemies_ai_var5



org $A88F8C

;;; $8F8C: Palette - enemy $E6BF (morph ball eye) ;;;
skip $20  ; Let SMART manage this
;dw 3800, 72B2, 71C7, 2461, 1840, 7A8E, 660B, 4D03, 4900, 7FE0, 7E80, 44E0, 2C20, 0000, 0000, 0000


;;; $8FAC: Instruction list -  ;;;
{
instrs_eye_directions:
	dw $000A,$9210
	dw $000A,$9210
	dw $000A,$9217
	dw $000A,$921E
	dw $000A,$9225
	dw $000A,$922C
	dw $000A,$9233
	dw $000A,$923A
	dw $000A,$9209
	dw $000A,$9202
	dw $000A,$91FB
	dw $000A,$91F4
	dw $000A,$91ED
	dw $000A,$91E6
	dw $000A,$91DF
	dw $000A,$91DF
	dw $80ED,instrs_eye_directions  ; Go to
}


;;; $8FF0: Instruction list -  ;;;
{
instrs_eye_left_closing:
	dw $0008,$9257
	dw $0030,$91F4
	dw $0005,$9257
.closed:
	dw $0030,$9241
	dw $812F  ; Sleep
}


;;; $9002: Instruction list -  ;;;
{
instrs_eye_right_closing:
	dw $0008,$9283
	dw $0030,$9225
	dw $0005,$9283
.closed:
	dw $0030,$926D
	dw $812F  ; Sleep
}


;;; $9014: Instruction list -  ;;;
{
instrs_eye_left_opening:
	dw $0020,$9241
	dw $0005,$9257
	dw $0030,$91F4
	dw $0008,$9257
	dw $812F  ; Sleep
}


;;; $9026: Instruction list -  ;;;
{
instrs_eye_right_opening:
	dw $0020,$926D
	dw $0005,$9283
	dw $0030,$9225
	dw $0008,$9283
	dw $812F  ; Sleep
}


;;; $9038: Instruction list -  ;;;
{
instrs_mount_right:
	dw $0001,$9299
	dw $812F  ; Sleep
}


;;; $903E: Instruction list -  ;;;
{
instrs_mount_down:
	dw $0001,$92A5
	dw $812F  ; Sleep
}


;;; $9044: Instruction list -  ;;;
{
instrs_mount_left:
	dw $0001,$92B1
	dw $812F  ; Sleep
}


;;; $904A: Instruction list -  ;;;
{
instrs_mount_up:
	dw $0001,$92BD
	dw $812F  ; Sleep
}


;;; $9050: Morph ball eye constants ;;;
{
; How close Samus needs to be for the eye to wake up and start tracking her
eye_acquire_xradius:
	dw $80
; How close Samus needs to be for the eye to continue tracking once it's already awake
eye_track_xradius:
	dw $B0
eye_acquire_yradius:
	dw $80
eye_track_yradius:
	dw $80
}


;;; $9058: Initialisation AI - enemy $E6BF (morph ball eye) ;;;
{
eye_ai_init:
	LDX enemy_index

	; Set "Process Instructions" flag
	LDA enemies_flags1,x
	ORA #$2000
	STA enemies_flags1,x

	LDA #!enemy_empty_spritemap
	STA enemies_spritemap,x

	LDA.w #1
	STA enemies_instruction_timer,x

	STZ enemies_timer,x

	; If (param2 & 8000h != 0) this is the mount part, initialize mount graphics
	LDA enemies_parameter2,x
	BMI .init_mount

	; Otherwise, this is the eye part, continue with eye initialization

	LDA #eye_state_waiting
	STA eye_vars_state,x

	; param1 & 0x0001 determines eye facing: 0 = Left, 1 = Right
	LDA enemies_parameter1,x
	BIT #$0001
	BEQ .facing_left

	; Right-facing
	LDA #instrs_eye_right_closing_closed
	STA enemies_instruction_list,x
	BRA .return

.facing_left:
	; Left-facing
	LDA #instrs_eye_left_closing_closed
	STA enemies_instruction_list,x
	BRA .return

.init_mount:
	; Depending on the mount orientation, offset origin and set sprite accordingly

	; Y = table offset for configured orientation ((param2 & Fh) * 2)
	AND #$000F
	ASL
	TAY

	; Offset X position
	LDA enemies_pos_x,x
	CLC
	ADC .x_offsets_tbl,y
	STA enemies_pos_x,x

	; Offset Y position
	LDA enemies_pos_y,x
	CLC
	ADC .y_offsets_tbl,y
	STA enemies_pos_y,x

	; Mount uses a null AI state
	LDA #rtl_91DC
	STA eye_vars_state,x

	; Set instruction list with correct sprites for this orientation
	LDA .instruction_lists_tbl,y
	STA enemies_instruction_list,x 

	; Fill $7E:9100..92FF ("some HDMA RAM"?) with 00FFh
	LDX #$01FE
-	LDA #$00FF
	STA ram_hdma_buffer,x
	DEX #2
	BPL -

.return:
	RTL

	;  Left, Right, Up, Down
.x_offsets_tbl:
	dw -8, 8, 0, 0
.y_offsets_tbl:
	dw 0, 0, -8, 8
.instruction_lists_tbl:
	dw instrs_mount_left, instrs_mount_right, instrs_mount_up, instrs_mount_down
}


;;; $90E2: Main AI - enemy $E6BF (morph ball eye) ;;;
{
eye_ai_main:
	LDX enemy_index
	LDA samus_collected_items
	BIT #$0004  ; Morph ball
	BEQ .return

	; If morph ball has been collected, run current AI state handler
	JMP (eye_vars_state,x)

.return:
	RTL
}


;;; $90F1: AI State: Eye closed, waiting for Samus to come nearby
{
eye_state_waiting:
	; Check if Samus is near the vicinity of the enemy and return otherwise
	LDA eye_acquire_yradius
	JSL ai_util_isSamusWithinYRadius
	TAY
	BEQ .return

	LDA eye_acquire_xradius
	JSL ai_util_isSamusWithinXRadius
	TAY
	BEQ .return

	LDA.w #32
	STA eye_vars_anim_delay,x

	LDA.w #1
	STA enemies_instruction_timer,x

	; Check facing direction (param1 & 0x0001), 0 = Left, 1 = Right
	LDA enemies_parameter1,x
	BIT #$0001
	BEQ .facing_left

	; Otherwise facing right
	LDA #instrs_eye_right_opening
	STA enemies_instruction_list,x
	BRA .next_state

.facing_left:
	LDA #instrs_eye_left_opening
	STA enemies_instruction_list,x
.next_state:
	LDA #eye_state_opening
	STA eye_vars_state,x
.return:
	RTL
}


;;; $912E: AI State: Eye spotted Samus and is playing opening animation
{
eye_state_opening:
	DEC eye_vars_anim_delay,x
	BEQ .eye_opened
	BPL .return

.eye_opened:
	; Queue sound 17h, sound library 2, max queued sounds allowed = 6 (morph ball eye's ray)
	LDA.w #$17
	JSL snd_playLib2Sfx

	JSL hdma_spawnEyeHdma
	LDA #eye_state_tracking
	STA eye_vars_state,x

	; Calculate angle from enemy to Samus
	LDA samus_pos_x
	SEC : SBC enemies_pos_x,x
	STA $12

	LDA samus_pos_y
	SEC : SBC enemies_pos_y,x
	STA $14

	JSL ai_util_atan2  ; Takes $12,$14 as params
	STA eye_vars_angle,x

.return:
	RTL
}


;;; $9160: AI State: Eye is open and tracking Samus' direction
{
eye_state_tracking:
	; Check if Samus is still near the eye object
	LDA eye_track_yradius
	JSL ai_util_isSamusWithinYRadius
	TAY
	BEQ .samus_out_of_range
	LDA eye_track_xradius
	JSL ai_util_isSamusWithinXRadius
	TAY
	BNE .track_samus

.samus_out_of_range:
	; Stop x-ray sound
	; Queue sound 71h, sound library 2, max queued sounds allowed = 6 (silence)
	LDA.w #$71
	JSL snd_playLib2Sfx

	STZ eye_vars_hdma_flag,x

	LDA.w #32
	STA eye_vars_anim_delay,x

	; Play eye closing animation. The correct instruction list is set
	; according to the eye direction. ((param1 & 1): 0=Left, 1=Right)
	LDA enemies_parameter1,x
	BIT #$0001
	BEQ .facing_left

	LDA #instrs_eye_right_closing
	STA enemies_instruction_list,x
	BRA .next_state
.facing_left:
	LDA #instrs_eye_left_closing
	STA enemies_instruction_list,x

.next_state:
	LDA #eye_state_closing
	STA eye_vars_state,x
	BRA .return

.track_samus:
	; Update beam angle by calculating new angle towards samus
	LDA samus_pos_x
	SEC : SBC enemies_pos_x,x
	STA $12

	LDA samus_pos_y
	SEC : SBC enemies_pos_y,x
	STA $14

	JSL ai_util_atan2  ; Takes $12,$14 as params
	STA eye_vars_angle,x

	; Update eye sprite to look in the correct direction. Uses the angle to
	; index into the instruction list containing each of the poses.

	; angle / 16 (num. of poses) * 4 (bytes per instruction in the list)
	AND #$00F0 : LSR #2
	CLC : ADC #instrs_eye_directions
	STA enemies_instruction_list,x

.return:
	LDA #$0001
	STA enemies_instruction_timer,x
	RTL
}


;;; $91CE: AI State: Eye lost track of Samus and is playing its closing animation before going back to waiting state
{
eye_state_closing:
	DEC eye_vars_anim_delay,x
	BEQ .counter_expired
	BPL .return

.counter_expired:
	LDA #eye_state_waiting
	STA eye_vars_state,x

.return:
	RTL
}


;;; $91DC: RTL
{
rtl_91DC:
	RTL
}


;;; $91DD: RTL (unused?)
{
rtl_91DD:
	RTL
}


;;; $91DE: RTL (unused?)
{
rtl_91DE:
	RTL
}


warnpc $A891DF

;;; $91DF: Morph ball eye spritemaps ;;;
{

macro sprmap_entry(xoff, yoff, tile)
	dw <xoff> : db <yoff> : dw <tile>
endmacro

; Open eye looking towards various angles
eye_spritemaps:
.f0:	dw 1 : %sprmap_entry($81F8, $F8, $2100)
.f1:	dw 1 : %sprmap_entry($81F8, $F8, $2102)
.f2:    dw 1 : %sprmap_entry($81F8, $F8, $2104)
.f3:    dw 1 : %sprmap_entry($81F8, $F8, $2106)
.f4:    dw 1 : %sprmap_entry($81F8, $F8, $2108)
.f5:    dw 1 : %sprmap_entry($81F8, $F8, $210A)
.f6:    dw 1 : %sprmap_entry($81F8, $F8, $210C)
.f7:    dw 1 : %sprmap_entry($81F8, $F8, $6100)
.f8:    dw 1 : %sprmap_entry($81F8, $F8, $6102)
.f9:    dw 1 : %sprmap_entry($81F8, $F8, $6104)
.f10:   dw 1 : %sprmap_entry($81F8, $F8, $6106)
.f11:   dw 1 : %sprmap_entry($81F8, $F8, $6108)
.f12:   dw 1 : %sprmap_entry($81F8, $F8, $610A)
.f13:   dw 1 : %sprmap_entry($81F8, $F8, $610C)

; Eye opening left
.f14:	dw 4
	%sprmap_entry($01F8, $00, $A11F)
	%sprmap_entry($01F8, $F8, $211F)
	%sprmap_entry($0000, $00, $2117)
	%sprmap_entry($0000, $F8, $2107)
.f15:	dw 4
	%sprmap_entry($01F8, $00, $A11E)
	%sprmap_entry($01F8, $F8, $211E)
	%sprmap_entry($0000, $00, $2117)
	%sprmap_entry($0000, $F8, $2107)
; Eye opening right
.f16:	dw 4
	%sprmap_entry($0000, $00, $E11F)
	%sprmap_entry($0000, $F8, $611F)
	%sprmap_entry($01F8, $00, $6117)
	%sprmap_entry($01F8, $F8, $6107)
.f17:	dw 4
	%sprmap_entry($0000, $00, $E11E)
	%sprmap_entry($0000, $F8, $611E)
	%sprmap_entry($01F8, $00, $6117)
	%sprmap_entry($01F8, $F8, $6107)

; Mount in 4 directions
.f18:	dw 2
	%sprmap_entry($01FC, $00, $A10E)
	%sprmap_entry($01FC, $F8, $210E)
.f19:	dw 2
	%sprmap_entry($0000, $FC, $610F)
	%sprmap_entry($01F8, $FC, $210F)
.f20:	dw 2
	%sprmap_entry($01FC, $00, $E10E)
	%sprmap_entry($01FC, $F8, $610E)
.f21:	dw 2
	%sprmap_entry($0000, $FC, $E10F)
	%sprmap_entry($01F8, $FC, $A10F)

; Unused. Seem to be duplicates of 9241-9298
.f22:	dw 4
	%sprmap_entry($01F8, $00, $A11F)
	%sprmap_entry($01F8, $F8, $211F)
	%sprmap_entry($0000, $00, $2117)
	%sprmap_entry($0000, $F8, $2107)
.f23:	dw 4
	%sprmap_entry($01F8, $00, $A11E)
	%sprmap_entry($01F8, $F8, $211E)
	%sprmap_entry($0000, $00, $2117)
	%sprmap_entry($0000, $F8, $2107)
.f24:	dw 4
	%sprmap_entry($0000, $00, $E11F)
	%sprmap_entry($0000, $F8, $611F)
	%sprmap_entry($01F8, $00, $6117)
	%sprmap_entry($01F8, $F8, $6107)
.f25:	dw 4
	%sprmap_entry($0000, $00, $E11E)
	%sprmap_entry($0000, $F8, $611E)
	%sprmap_entry($01F8, $00, $6117)
	%sprmap_entry($01F8, $F8, $6107)
.f26:	dw 4
	%sprmap_entry($0000, $00, $E11F)
	%sprmap_entry($0000, $F8, $611F)
	%sprmap_entry($01F8, $00, $6117)
	%sprmap_entry($01F8, $F8, $6107)
.f27:	dw 4
	%sprmap_entry($0000, $00, $E11E)
	%sprmap_entry($0000, $F8, $611E)
	%sprmap_entry($01F8, $00, $6117)
	%sprmap_entry($01F8, $F8, $6107)
.f28:	dw 4
	%sprmap_entry($01F8, $00, $A11F)
	%sprmap_entry($01F8, $F8, $211F)
	%sprmap_entry($0000, $00, $2117)
	%sprmap_entry($0000, $F8, $2107)
.f29:	dw 4
	%sprmap_entry($01F8, $00, $A11E)
	%sprmap_entry($01F8, $F8, $211E)
	%sprmap_entry($0000, $00, $2117)
	%sprmap_entry($0000, $F8, $2107)
}

}

; End of eye code
warnpc $A89379