Decompilation of move_sprite_to_list (0x0069ED0B)

src/peep.c

@@ -65,7 +65,7 @@ void peep_update_all()
 			peep_update(peep);
 		} else {
 			RCT2_CALLPROC_X(0x0068F41A, 0, 0, 0, i, (int)peep, 0, 0);
-			if (peep->var_08 == 4)
+			if (peep->linked_list_type_offset == SPRITE_LINKEDLIST_OFFSET_PEEP)
 				peep_update(peep);
 		}
 

src/peep.h

@@ -308,7 +308,7 @@ typedef struct {
 	uint16 var_02;					// 0x02
 	uint16 next;					// 0x04
 	uint16 previous;				// 0x06
-	uint8 var_08;
+	uint8 linked_list_type_offset;	// 0x08 Valid values are SPRITE_LINKEDLIST_OFFSET_...
 	uint8 var_09;					// 0x09
 	uint16 sprite_index;			// 0x0A
 	uint16 var_0C;

src/ride.c

@@ -184,7 +184,7 @@ void ride_update_favourited_stat()
 		ride->guests_favourite = 0;
 
 	FOR_ALL_PEEPS(spriteIndex, peep) {
-		if (peep->var_08 != 4)
+		if (peep->linked_list_type_offset != SPRITE_LINKEDLIST_OFFSET_PEEP)
 			return;
 		if (peep->favourite_ride != 0xff) {
 			ride = &g_ride_list[peep->favourite_ride];

src/sprite.c

@@ -53,7 +53,7 @@ void reset_sprite_list(){
 		spr->unknown.sprite_identifier = 0xFF;
 		spr->unknown.sprite_index = i;
 		spr->unknown.next = SPRITE_INDEX_NULL;
-		spr->unknown.var_08 = 0;
+		spr->unknown.linked_list_type_offset = 0;
 
 		if (previous_spr != (rct_sprite*)SPRITE_INDEX_NULL){
 			spr->unknown.previous = previous_spr->unknown.sprite_index;
@@ -108,11 +108,11 @@ void reset_0x69EBE4(){
 
 /*
 * rct2: 0x0069EC6B
-* bl: unclear what this does
+* bl: if bl & 2 > 0, the sprite ends up in the FLOATING_TEXT linked list.
 */
 rct_sprite *create_sprite(uint8 bl)
 {
-	int ecx = 0xA;
+	int linkedListTypeOffset = SPRITE_LINKEDLIST_OFFSET_FLOATING_UNKNOWN; // cl
 
 	if ((bl & 2) != 0)
 	{
@@ -123,7 +123,7 @@ rct_sprite *create_sprite(uint8 bl)
 			return NULL;
 		}
 
-		ecx = 6;
+		linkedListTypeOffset = SPRITE_LINKEDLIST_OFFSET_FLOATING_TEXT;
 	}
 	else if (RCT2_GLOBAL(0x13573C8, uint16) <= 0)
 	{
@@ -132,7 +132,7 @@ rct_sprite *create_sprite(uint8 bl)
 
 	rct_unk_sprite *sprite = &(g_sprite_list[RCT2_GLOBAL(RCT2_ADDRESS_SPRITES_NEXT_INDEX, uint16)]).unknown;
 
-	RCT2_CALLPROC_X(0x0069ED0B, 0, 0, ecx, 0, (int)sprite, 0, 0);
+	move_sprite_to_list(sprite, linkedListTypeOffset);
 
 	sprite->x = SPRITE_LOCATION_NULL;
 	sprite->y = SPRITE_LOCATION_NULL;
@@ -148,4 +148,56 @@ rct_sprite *create_sprite(uint8 bl)
 	RCT2_GLOBAL(0xF3EF60, uint16) = sprite->sprite_index;
 
 	return (rct_sprite*)sprite;
+}
+
+/*
+* rct2: 0x0069ED0B
+* This function moves a sprite to the specified sprite linked list.
+* There are 5/6 of those, and cl specifies a pointer offset 
+* of the desired linked list in a uint16 array. Known valid values are
+* 2, 4, 6, 8 or 10 (SPRITE_LINKEDLIST_OFFSET_...)
+*/
+void move_sprite_to_list(rct_sprite *sprite, uint8 cl)
+{
+	rct_unk_sprite *unkSprite = sprite;
+
+	// No need to move if the sprite is already in the desired list
+	if (unkSprite->linked_list_type_offset == cl)
+		return;
+
+	// If the sprite is currently the head of the list, the 
+	// sprite following this one becomes the new head of the list.
+	if (unkSprite->previous == SPRITE_INDEX_NULL)
+	{
+		RCT2_GLOBAL(RCT2_ADDRESS_SPRITES_NEXT_INDEX + unkSprite->linked_list_type_offset, uint16) = unkSprite->next;
+	}
+	else
+	{
+		// Hook up sprite->previous->next to sprite->next, removing the sprite from its old list
+		g_sprite_list[unkSprite->previous].unknown.next = unkSprite->next;
+	}
+
+	// Similarly, hook up sprite->next->previous to sprite->previous
+	if (unkSprite->next != SPRITE_INDEX_NULL)
+	{
+		g_sprite_list[unkSprite->next].unknown.previous = unkSprite->previous;
+	}
+
+	int oldListTypeOffset = unkSprite->linked_list_type_offset;
+	unkSprite->previous = SPRITE_INDEX_NULL; // We become the new head of the target list, so there's no previous sprite
+	unkSprite->linked_list_type_offset = cl;
+
+	unkSprite->next = RCT2_GLOBAL(RCT2_ADDRESS_SPRITES_NEXT_INDEX + cl, uint16); // This sprite's next sprite is the old head, since we're the new head
+	RCT2_GLOBAL(RCT2_ADDRESS_SPRITES_NEXT_INDEX + cl, uint16) = unkSprite->sprite_index; // Store this sprite's index as head of its new list
+
+	if (unkSprite->next != SPRITE_INDEX_NULL)
+	{
+		// Fix the chain by settings sprite->next->previous to sprite_index
+		g_sprite_list[unkSprite->next].unknown.previous = unkSprite->sprite_index;
+	}
+
+	// These globals are probably counters for each sprite list?
+	// Decrement old list counter, increment new list counter.
+	--(RCT2_GLOBAL(0x13573C8 + oldListTypeOffset, uint16));
+	++(RCT2_GLOBAL(0x13573C8 + cl, uint16));
 }

src/sprite.h

@@ -36,13 +36,21 @@ enum SPRITE_IDENTIFIER{
 	SPRITE_IDENTIFIER_LITTER = 3,
 };
 
+enum {
+	SPRITE_LINKEDLIST_OFFSET_VEHICLE = 2,
+	SPRITE_LINKEDLIST_OFFSET_PEEP = 4,
+	SPRITE_LINKEDLIST_OFFSET_FLOATING_TEXT = 6,
+	SPRITE_LINKEDLIST_OFFSET_FLOATING_LITTER = 8,
+	SPRITE_LINKEDLIST_OFFSET_FLOATING_UNKNOWN = 10
+};
+
 typedef struct {
 	uint8 sprite_identifier;		// 0x00
 	uint8 pad_01;
 	uint16 var_02;
 	uint16 next;					// 0x04
 	uint16 previous;				// 0x06
-	uint8 var_08;
+	uint8 linked_list_type_offset;	// 0x08 Valid values are SPRITE_LINKEDLIST_OFFSET_...
 	uint8 pad_09;
 	uint16 sprite_index;			// 0x0A
 	uint8 pad_0C[2];
@@ -66,7 +74,7 @@ typedef struct {
 	uint16 var_02;					// 0x02
 	uint16 next;					// 0x04
 	uint16 previous;				// 0x06
-	uint8 var_08;
+	uint8 linked_list_type_offset;	// 0x08 Valid values are SPRITE_LINKEDLIST_OFFSET_...
 	uint8 pad_09;
 	uint16 sprite_index;			// 0x0A
 	uint8 pad_0B[0x19];
@@ -92,5 +100,6 @@ void create_balloon(int x, int y, int z, int colour);
 rct_sprite *create_sprite(uint8 bl);
 void reset_sprite_list();
 void reset_0x69EBE4();
+void move_sprite_to_list(rct_sprite *sprite, int ecx);
 
 #endif

src/staff.c

@@ -127,7 +127,7 @@ void game_command_hire_new_staff_member(int* eax, int* ebx, int* ecx, int* edx,
 		RCT2_CALLPROC_X(0x0069EDB6, 0, 0, _ecx, 0, (int)newPeep, 0, 0);
 	}
 	else {
-		RCT2_CALLPROC_X(0x0069ED0B, 0, 0, 4, 0, (int)newPeep, 0, 0);
+		move_sprite_to_list(newPeep, 4);
 
 		newPeep->sprite_identifier = 1;
 		newPeep->var_09 = 0x0F;

src/vehicle.h

@@ -36,7 +36,7 @@ typedef struct {
 	uint8 pad_01[0x03];
 	uint16 next;					// 0x04
 	uint16 previous;				// 0x06
-	uint8 var_08;
+	uint8 linked_list_type_offset;	// 0x08 Valid values are SPRITE_LINKEDLIST_OFFSET_...
 	uint8 pad_09;
 	uint16 sprite_index;			// 0x0A
 	uint8 pad_0C[2];