Course Paths

Each track (except the battle courses) have a set of paths, used to define the race course and the paths of some objects. Their locations are hardcoded RSP addresses:

Track	Address
0x00 Mario Raceway	06:005568
0x01 Choco Mountain	06:004480
0x02 Bowser's Castle	06:004F90
0x03 Banshee Boardwalk	06:004578
0x04 Yoshi Valley	06:00D780, 06:00D9C8, 06:00DC18, 06:00DEA8
0x05 Frappe Snowland	06:0034A0
0x06 Koopa Troopa Beach	06:00ADE0
0x07 Royal Raceway	06:00B5B8
0x08 Luigi Raceway	06:00A540
0x09 Moo Moo Farm	06:00EC80
0x0A Toad's Turnpike	06:003B80
0x0B Kalimari Desert	06:006AC8
0x0C Sherbet Land	06:004BF8
0x0D Rainbow Road	06:001D90
0x0E Wario Stadium	06:0056A0
0x12 DK's Jungle Parkway	06:0071F0

(XXX why does Yoshi Valley have four?)

The path is an array of points:

struct mk64_3dpoint {
	int16_t X, Y, Z;
	uint16_t unknown;
};

The path ends when X == 0x8000. If Y == 0x8000 && Z == 0x8000, the set ends, otherwise, another path begins.

Each set contains at least two paths. The first has few points (usually fewer than 100), with Y == 0 && unknown == 0. The second has many points, laid directly on the track, with unknown gradually increasing, roughly correlated with the area ID. The second seems to be used for tracking each player's progress in the race.

The AI players follow these paths (XXX which ones?) automatically while off-screen, and will teleport back to them if they stray too far.

Some tracks have more than two paths:

• Koopa Troopa Beach has four:
  • The first one, whose purpose is unknown
  • The second, which defines the main route
  • The third, which follows the main route but goes left around the stone turtle; all points have unknown = 0
  • The fourth, which follows the main route but takes the shortcut across the sandbar (to the right of the 3 ramps); all points have unknown = 7
  • No path goes through the tunnel
• Yoshi Valley has four, defining various routes
  • The extra paths' unknown values are 4 and 7 for all points
• Kalimari Desert has a path for the train to follow
  • A player can follow this path and complete a lap, but only while using a star. The game won't count the lap otherwise. XXX find the code that does this.
• DK's Jungle Parkway has a path for the boat to follow

At ROM address 0xDD380 is a table with 4 entries per course, containing the RSP addresses of each path. Unused entries are set to 0x800DC778 (which is not an RSP address); at this RAM address is 0x8000 0x0000 0x0000 0x0000, which marks the end of a path, but should be immediately followed by another path. This table doesn't seem to be used at all? (XXX)