river-raid: Routine at 7415

7415: Handle helicopter missile collision

Called by the sprite renderer's pixel collision when the missile's $FF byte overlaps solid screen pixels (bank or island terrain). Checks whether the overlap is actually the player plane; if not, clears the missile. Triggered by terrain contact (solid pixels), not player proximity If missile Y is not at player level (bit 7 clear), clear missile immediately Otherwise check missile X against player X; if match, player hit On miss: clears missile and pops return addresses to abort collision chain
handle_collision_mode_helicopter_missile	7415	LD BC,($5F73)	Load missile coords. If Y bit 7 clear, clear missile and return.
	7419	BIT 7,B
	741B	JP Z,handle_collision_mode_missile_miss	Clear Y bit 7, check if Y-8 is negative (missile above screen).
	741E	RES 7,B
	7420	LD A,B
	7421	SUB $08
	7423	JP P,handle_collision_mode_missile_miss	Compare missile X with player X (from state_plane_x). If match, player hit.
	7426	LD A,($5F72)
	7429	AND $F8
	742B	CP C
	742C	JP Z,handle_player_death
	742F	ADD A,$08	Check adjacent X position. If match, player hit.
	7431	CP C
	7432	JP Z,handle_player_death
handle_collision_mode_missile_miss	7435	LD BC,$0000	Clear missile coords, pop 4 return addresses, return.
	7438	LD ($5F73),BC
	743C	POP DE
	743D	POP DE
	743E	POP DE
	743F	POP DE
	7440	RET