Help:Patching the motorcycle area checks

Because of arbitrary, hardcoded limitations, the Master Cycle Zero cannot be used in some areas. This article lists and documents checks that must be patched to remove usage restrictions.

Most of them are located in the MotorcycleMgr.

Check

The game uses the current climate for the area check:

• ✅ HyrulePlainClimate
• ✅ NorthHyrulePlainClimate
• ✅ HebraFrostClimate
• ✅ TabantaAridClimate
• ✅ FrostClimate
• 🚫 GerudoDesertClimate
• ✅ GerudoPlateauClimate
• ✅ EldinClimateLv0
• ✅ TamourPlainClimate
• ✅ ZoraTemperateClimate
• ✅ HateruPlainClimate
• ✅ FiloneSubtropicalClimate
• ✅ SouthHateruHumidTemperateClimate
• 🚫 EldinClimateLv1
• 🚫 EldinClimateLv2
• ✅ DarkWoodsClimat
• ✅ LostWoodClimate
• ✅ GerudoFrostClimate
• ✅ KorogForest
• 🚫 GerudoDesertClimateLv2

Patching

• On Switch, read the rest of the article to understand what to patch.
• On Wii U, the checks are implemented in the exact same way (which makes sense since it's the same codebase), but only a single instruction has to be patched because the Wii U compiler is not quite as good at inlining functions. Simply patch the instruction at 0x02A32A30 to li r3, 1.

Technical details

Note: the addresses below are only valid for Switch 1.5.0. Other versions (on Switch or Wii U) can be patched in a similar way, though.

Disappearing when entering a blacklisted climate

Called from the Motorcycle AI root code.

if ( v6 && !MotorcycleMgr::motorcycleCanBeUsed(v6, (float *)&v68, 0LL) )  // 0x71004ADF18
  goto triggerDisappear;

Either change the condition to be always false, or change MotorcycleMgr::motorcycleCanBeUsed (preferred to avoid side effects):

bool MotorcycleMgr::motorcycleCanBeUsed(MotorcycleMgr* this, Vec3 *positions, __int64 a3) // 0x7100679D10
{
  if ( (a3 || (a3 = ActorSystem::sInstance->field_C0) != 0)
    && (*(__int64 (__fastcall **)(__int64))(*(_QWORD *)a3 + 0x180LL))(a3) & 1 )
  {
    return false;
  }
  if ( WorldMgr::sInstance
         && (v5 = (u64)WorldMgr::getClimateNum(WorldMgr::sInstance, positions) - 5, v5 <= 14) )
  {
    return (0x3CFEu >> v5) & 1;
  }
  return true;
}

Patch:

.text:0000007100679D84                 AND             W0, W8, #1

To:

.text:0000007100679D84                 MOV             W0, #1

Rune UI/sound effect

Same climate based check as above, but done in a different MotorcycleMgr function. Just change:

.text:0000007100679650 TBNZ            W8, #0, loc_710067965C

to:

.text:0000007100679650 B               loc_710067965C

Refusing to spawn when in a blacklisted climate

Check 1

Deep in some MotorcycleMgr function, called from the PlayerNormal AI:

else if ( !WorldMgr::sInstance
       || (v7 = (unsigned __int64)WorldMgr::getClimateNum(WorldMgr::sInstance, (float *)v4) - 5, v7 > 0xE)
       || (0x3CFEu >> v7) & 1 )
{
  v8 = (*(__int64 (**)(void))(**(_QWORD **)(HavokAI::sInstance->navMeshQueryReqPool + 0x1A0LL) + 0x30LL))();
  ...
}

Patch:

.text:0000007100679BA8                 CBZ             X0, loc_7100679BD8

to:

.text:0000007100679BA8                 B               loc_7100679BD8

so that the game always executes the code inside of the if block.

Check 2

Found in another MotorcycleMgr member function and also called from the PlayerNormal AI code.

bool MotorcycleMgr::checkUsable2(MotorcycleMgr *this, __int64 a2)
{
  if ( this->someFlag == 1 )
    return 0;
  float* v4 = this->gap12C;
  MotorcycleMgr::x_7(this, (float *)this->gap12C, (__int64)&this->field_134 + 4);
  if ( a2 || (a2 = ActorSystem::sInstance->field_C0) != 0 )
  {
    if ( (*(__int64 (__fastcall **)(__int64))(*(_QWORD *)a2 + 0x180LL))(a2) & 1 )
      return 0;
  }
  if ( !WorldMgr::sInstance )
    return 1;
  unsigned int climateNumMinus5 = WorldMgr::getClimateNum(WorldMgr::sInstance, v4) - 5;
  return ( climateNumMinus5 > 14 || (0x3CFEu >> climateNumMinus5) & 1 );
}

Change:

.text:000000710067B5FC                 CBZ             X0, loc_710067B62C

to:

.text:000000710067B5FC                 B               loc_710067B62C

to make the game always return “true”.

Disappearing when being away from the motorcycle

This is checked by Motorcycle AI root code (at 0x71004ADF28).

v40 = (float *)PlayerInfo::getPlayerPos(PlayerInfo::sInstance);
if ( (float)((float)((float)(*(float *)&v68 - *v40) * (float)(*(float *)&v68 - *v40))
           + (float)((float)(*(float *)&v70 - v40[2]) * (float)(*(float *)&v70 - v40[2]))) > (float)(**(float **)&this->_4abuf[8] * **(float **)&this->_4abuf[8]) )
  goto triggerDisappear;

It is easy to change this condition to be always false.

Other checks

There are a few more conditions for spawning the motorcycle; however patching them is not recommended as they are implemented for good reasons.

Actor check

If the actor cannot be loaded, the game will not allow the player to use the motorcycle and will show the regular “You can’t use that here” message.

6 or 7 other checks

The MotorcycleMgr function at 0x7100678E80 (which can be identified with a xref to "GameROMMotorcycle") calls 6 member functions that must all return true; otherwise, the motorcycle cannot be used.

The first 4 functions appear to be using the Havok AI NavMesh system. Something called “motorcycle shape cast” is used in the 3 other functions.