# Lap & Speed Modifier

Lap & Speed Modifier is a Mario Kart Wii extension that modifies the number of laps and the basic speed of a race. It was developed by MrBean35000vr for CTGP Revolution v1.03 with help from Geeh and MrEvil and is also available as a pair of cheat codes.

## How it works (STGI)

The Lap & Speed Modifier reads some values of KMP/STGI:

• The byte at offset 0 is used for the number of laps, if it is between 1 and 9.
• The 2 bytes at offsets 0x0A and 0x0B are interpreted as the 2 most significant bytes of the floating point speed factor. The least significant two bytes of the speed factor are always 0. If the speed modifier equals 0.0 a value of 1.0 is used instead (for backwards compatibility with tracks not using a Speed modifier). The usual range is 0.5 (0x3F00) to 2.0 (0x4000).

### Speed Factor Discussion

The tracks are generally designed for speed factor 1.0. With it, a player can increment its position up to 120 game units if using a mushroom or Bullet Bill. If using a speed factor of 2.0, the increment can be 2*120 = 240 game units. So it is possible to miss walls, items or opponents if, in one calculation, the vehicle was behind the object and on the next calculation, in front of the object. While testing speed factor 3, Wiimm and Leseratte slipped through Item and Fake Item Boxes.

Another relevant factor is the blow factor of the cubes if creating a KCL. For optimization, the world is generally divided into cubes of 512*512*512 units and only the triangle list for the current cube is used to find collisions. It is important that near neighboring triangles, cubes are also included into the triangle list for the cube. Nintendo blows up the cubes by factor ~3.35 (KCL_BLOW=600 or --kcl=CHARY for Wiimms SZS Tools) to find neighboring triangles. If using option --kcl=SMALL, then only 200 units are used. This value is enough for speed factor 1.0, but may be too small for factor 2.0.

Another point are checkpoints. If they are placed too near, you can miss some checkpoints. And if you miss a key checkpoint, the result is a no-lap-count bug.

So the best is to use never speed factors >2.0!

## Cheat Codes

Cheat codes are available for 4 regions. The cheat codes are already built into LE-CODE:

## Wiimms SZS Tools

### Patching Track Files

The values of the STGI section can easily be patched by the tool wszst:

• wszst patch --speed-mod=factor ... will change the speed factor.
• wszst patch --kmp=3laps ... will patch the lap number. Values between 1lap and 9laps are possible (however, 9 laps don't work correctly in the game for some reason, it will display 8 laps but actually drive for 9 laps).
• wszst patch --kmp=MODE ... will patch the pole position (modes left or right) and/or the narrow mode (modes wide or narrow).

### Patching main.dol to enable LS-Mod support

wstrt patch supports the option --add-section=file to add a section to file main.dol. The section can be a gecko code interpreter together with some cheat codes.