Knight Lore: Routine at D1EF

Used by the routine at build_screen_objects.

Clears the screen buffer; builds the room's walls, arches and fixed objects into records 4 onwards (retrieve_screen); puts any collectable objects in this room into records 2 and 3 (find_special_objs_here); and places the player in the doorway he came through (adjust_plyr_xyz_for_room_size). Then resets the per-room state and asks for the whole room to be drawn and copied to the screen ($5BB7).

$5BAF is the portcullis-moving flag and $5BB0 a count the portcullis code keeps; $5BBD is the bouncing ball's turning height and $5BBF the spiked-ball-falling flag. $5BC0 takes bit 0 of the room number: the dropping spiked balls (upd_63) stay put while it is non-zero; picking an object up (pickup_object) or collecting an extra life (upd_103) clears it.

Used by the routine at build_screen_objects. Clears the screen buffer; builds the room's walls, arches and fixed objects into records 4 onwards (retrieve_screen); puts any collectable objects in this room into records 2 and 3 (find_special_objs_here); and places the player in the doorway he came through (adjust_plyr_xyz_for_room_size). Then resets the per-room state and asks for the whole room to be drawn and copied to the screen ($5BB7). $5BAF is the portcullis-moving flag and $5BB0 a count the portcullis code keeps; $5BBD is the bouncing ball's turning height and $5BBF the spiked-ball-falling flag. $5BC0 takes bit 0 of the room number: the dropping spiked balls (upd_63) stay put while it is non-zero; picking an object up (pickup_object) or collecting an extra life (upd_103) clears it.
build_room	D1EF	CALL clear_scrn_buffer	build the room
	D1F2	CALL retrieve_screen	build the room
	D1F5	CALL find_special_objs_here
	D1F8	CALL adjust_plyr_xyz_for_room_size
	D1FB	XOR A	clear the per-room flags
	D1FC	LD ($5BAF),A
	D1FF	LD ($5BB0),A
	D202	LD ($5BBD),A
	D205	LD ($5BBF),A
	D208	LD A,$01	draw the whole room this frame
	D20A	LD ($5BB7),A
	D20D	LD A,($5C10)	odd rooms hold their spiked balls
	D210	AND $01
	D212	LD ($5BC0),A
	D215	CALL flag_room_visited	the room counts as visited
	D218	RET	the room counts as visited