Chase Scene

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The chase scene is part of the introduction sequence of Grand Theft Auto III.

Data files

The CHASE*.DAT files are a set of binary files that set the paths and some behaviors of cars seen in the introduction cutscene of the game. They are located in the \data\paths\ folder. Each entry is 28 bytes in size, with the following format:

Offset Type Description
0x00 word[3] velocity in x,y,z direction
0x06 char[3] right x,y,z
0x09 char[3] top x,y,z
0x0C char steering angle
0x0D char gas pedal power
0x0E char brake pedal power
0x0F char handbrake used
0x10 float[3] x,y,z position

Mission script

The following commands along with their details relate directly to the chase scene in the game's mission script.

START_CHASE_SCENE

START_CHASE_SCENE (opcode 0354) is a command that starts the chase scene. The scene consists of 13 unique cars following paths defined in the CHASE*.DAT files. The minimum to get the chase scene to look decent is to start the cutscene "JB" with the appropriate cutscene objects, make the player safe using MAKE_PLAYER_SAFE_FOR_CUTSCENE, and load the level collision using LOAD_COLLISION. Depending on the implementation of the code, anything less can result in many undesirable behaviors, including crashing the game, unusual cycling of colors on cars, creating random collisional damages on cars, making the cars not move, or inability for the player to enter any cars. The game performs the loading of all car models for the scene so you do not need to load the models yourself. During the scene, many parts of the city's collision unloads.

The following table is the initialization of cars and their properties when the opcode is called. The index corresponds to which chase path to use. The data is located in a function at memory address 0x435810 for US v1.0.

Index Car Location Heading Color
0 116 Police 273.5422 -1167.1907 24.9906 63.0 2 1
1 117 Enforcer 231.1783 -1388.8322 25.9782 90.0 2 1
2 130 Rumpo -28.9762 -1031.3367 25.9781 242.0 1 75
3 96 Patriot 114.1564 -796.6938 24.9782 180.0 0 0
4 110 Taxi 184.3156 -1473.251 25.9782 0.0 6 6
6 105 Cheetah 173.8868 -1377.6514 25.9782 0.0 4 5
7 92 Stinger 102.5946 -943.9363 25.9781 270.0 53 53
10 105 Cheetah 177.7157 -862.1865 25.9782 155.0 41 1
11 92 Stinger 170.5698 -889.0236 25.9782 154.0 10 10
14 111 Kuruma 402.6081 -917.4963 37.381 90.0 34 1
16 110 Taxi -33.4962 -938.4563 25.9781 266.0 6 6
18 111 Kuruma 49.3631 -987.605 25.9781 0.0 51 1
19 110 Taxi 179.0049 -1154.6686 25.9781 0.0 6 76

STOP_CHASE_SCENE

STOP_CHASE_SCENE (opcode 0355) is a command that stops the chase scene started by START_CHASE_SCENE by deleting all cars from the scene. The chase scene causes many parts of the city's collision to unload so, in order to restore the collision, place the player character outside Staunton Island to force the loading of level collisions.

REMOVE_CAR_FROM_CHASE

REMOVE_CAR_FROM_CHASE (opcode 040A) is a command that removes the car from the chase scene started by START_CHASE_SCENE.

GET_CHASE_CAR

GET_CHASE_CAR (opcode 0439) is a command that gets the car from the chase scene started by START_CHASE_SCENE. The car is also released from the chase scene and no longer follows its path. This command was never called in the original script of GTA III.

See also

External link