Avalon: Routine at 51702

51702: Check if Maroc is moving through an open doorway


Door has been identified as OPEN. Because door positions vary when open depending on the wall section they sit in, the next routine adjusts the doorway exit point, based on the open door's graphic position. After this adjustment has been made the collision detection routine at 57301 is used to determine if Maroc is moving through the doorway.
51702	LD A,(60079)	Door graphic's horizontal position offset
51705	CP 248	Door graphic's horizontal position offset
51707	JR Z,51717	The only door frame with this value offset is the back wall open door
51709	CP 232
51711	JR Z,51721	The only door frame with this value offset is the right wall open door
51713	LD A,248	Horizontal pixel offset for left wall open door left wall open door (-8 pixels)
51715	JR 51723
51717	LD A,12	Horizontal pixel offset for the back wall open door (+12 pixels)
51719	JR 51723
51721	LD A,8	Horizontal pixel offset for the right wall open door (+8 pixels)
Add the adjusted offset to door horizontal pixel position
51723	LD B,A	Get the pixel offset for this door's exit/entry point
51724	LD A,(60115)	Get the door's horizontal pixel position
51727	ADD A,B	Add the pixel offset
51728	LD D,A	Store in the D register - used for the horizontal 'hit box' for collision check in CALL at 51737 (to 57301)
51729	LD A,(60114)	Get the door's vertical pixel position
51732	SUB 8	Small (-8 pixel) vertical adjustment
51734	LD E,A	Store in E register - used for the vertical 'hit box' for collision check in CALL at 51737 (to 57301)
51735	LD C,0	Collision type = 0 - this is the collision/event ID for checks against Maroc's position
51737	CALL 57301	Check for collision
51740	CP 0	A register returned with 1 = collision, 0 = no collision
51742	JR NZ,51762	If there's a collision, skip the next few instructions
No collision detected on that check
51744	LD A,E	Retrieve previously adjusted horizontal pixel check position
51745	SUB 4	Make a further small (-4 more pixels) horizontal adjustment
51747	LD E,A	Store back in E register (horizontal 'hit box' check)
51748	LD A,(60115)	Door vertical pixel position
51751	LD D,A	Retrieve vertical 'hit box' pixel position from D register
51752	LD C,0	Collision type = 0 - this is the collision/event ID for checks against Maroc's position
51754	CALL 57301	Check for collision
51757	CP 0	Check for collision
51759	JP Z,51958	No collision, can jump out of routine here
Collision detected - Maroc is within range of the open door. Check he's actually moving towards it.
51762	LD A,(60079)	Retrieve door graphic's horizontal pixel graphic offset
51765	CP 248	Offset for the back wall open door
51767	JR Z,51788	Offset for the back wall open door
51769	CP 232	Offset for the right wall open door
51771	LD A,(60164)	Get Maroc's horizontal movement speed as it'll need to be evaluated for left and right wall doors
51774	JR Z,51803
Door is a left wall open door. Check Maroc's horizontal movement:
51776	CP 0	Is Maroc moving left or right?
51778	JP Z,51958	If not, skip out of this routine
51781	CP 128	If not, skip out of this routine
51783	JP NC,51958	Skip out of this routine if Maroc is moving right
51786	JR 51813	...otherwise Maroc is moving left, so send him through the doorway
Door is a back wall open door. Check Maroc's vertical movement:
51788	LD A,(60165)	Maroc's vertical movement speed
51791	CP 0	Is Maroc moving up or down?
51793	JP Z,51958	If not, skip out of this routine
51796	CP 128	If not, skip out of this routine
51798	JP NC,51958	Skip out of this routine if Maroc is moving down
51801	JR 51813	...otherwise Maroc is moving upwards, so send him through the doorway
Door is a right wall open door. Check Maroc's horizontal movement:
51803	CP 0	Is Maroc moving left or right?
51805	JP Z,51958	If not, skip out of this routine
51808	CP 128	If not, skip out of this routine
51810	JP C,51958	Skip out of this routine if Maroc is moving left ...otherwise Maroc is moving right, so send him through the doorway (continue to the next routine)