GTA Viewer

This is an engine\viewer for the top-down Grand Theft Auto games.

It supports the following GTA games:

• GTA 1
• GTA 1 demos (regular, 3DFX, ECTS)
• GTA London (1969 and 1961)
• GTA 2
• GTA 2 demo

It is not feature complete, lacking the following abilities:

• GTA 2 sound sequences (causing wrong ambient sounds to play).
• Map meta-data like routes, spawn points and drive arrows are not displayed.
• GTA 2 point lights are not rendered.

Usage

In order to run GTA Viewer you will need to place files from a valid GTA game in an appropriately named subdirectory of the /base directory. You can use one of the following subdirectory names:

• gta1: GTA 1
• gta1demo: GTA 1 Demo
• gta1demo3dfx: GTA 1 3DFX Demo
• gta1demoects: GTA 1 ECTS Demo
• uk: GTA London 1969
• uk1961: GTA London 1961
• gta2: GTA 2
• gta2demo: GTA 2 Demo

For the GTA 1 and GTA: London games, copy all data inside the /gtadata directory into the corresponding /base/gta1* or /base/uk* directories. For GTA 2 games, copy all data inside the /data directory into the corresponding /base/gta2* directory. Any version of the game's data files should work, including versions released through Steam.

To configure what game directory should be used, edit the /data/config.json file, and modify the g_basedir value to the directory name containing the game data you want to use.

Configuration

The /data/config.json file contains a number of variables that can be modified. The most useful ones are:

• g_basedir: sets the directory inside the /base directory that contains the files to run GTA Viewer with.
• r_width & r_height: these values set the width and height of the window to diusplay the viewer in, or the resolution of the fullscreen mode (see r_fullscreen).
• g_dusk: set to 1 if GTA 2 levels should be played in dusk lighting mode.
• g_fov: sets the field of view of the camera.
• g_mission: sets the mission index to view. This will load the appropriate map, script and style for the specified mission.
• r_aasamples: sets the number of anti-aliasing samples to use to smooth out edges.
• r_anisotropy: sets the number of anisotropy samples to use to produce more accurate texture filtering at steep angles.
• r_dumpblocktextures: if set to 1, all of the loaded style's block textures will be written to the /blocktextures directory.
• r_dumpsprites: if set to 1, all of the loaded style's sprites will be written to the /sprites directory.
• r_dumpspritetextures: if set to 1, all of the loaded style's sprites will be written to the /spritetextures directory as sprite sheets.
• r_filter: if set to 1, texture filtering will be applied. To emulate GTA 1's lack of texture filtering, set this to 0.
• r_frameratelimit: if r_vsync is 0, this will dictate the maximum framerate to render at.
• r_fullscreen: if set to 1, will display the viewer in fullscreen mode instead of in a window.
• r_shadows: if set to 1, draws faux shadows under sprites. This also works in GTA 1 games.
• r_vsync: if set to 1, will enable vsync to synchronize screen refreshes with the display refresh rate, leading to smoother motion.

Compiling

GTA Viewer can be compiled using the included Visual Studio 2013 project, as well as an installation of D and Visual D. The following libraries are also required:

• Derelict SDL2: https://github.com/DerelictOrg/DerelictSDL2
• Derelict OpenGL 3: https://github.com/DerelictOrg/DerelictGL3
• Derelict OpenAL: https://github.com/DerelictOrg/DerelictAL

Notices

• Contains code based on Epic GTA2 Script Decompiler by T.M.
• fast-hash implementation converted from https://code.google.com/p/fast-hash/
• Matrix math functions adapted from https://github.com/coreh/gl-matrix.c by Marco Aurélio
• Bin packing functionality adapted from https://github.com/jakesgordon/bin-packing by Jake Gordon
• Grand Theft Auto, Grand Theft Auto 2, Grand Theft Auto London 1969 and Grand Theft Auto London 1961 are registered trademarks from Rockstar Games, Inc.