Speed Dreams, often shortened to and formerly known as , is a free and open source 3D racing video game for Linux, Microsoft Windows, AmigaOS 4, AROS, MorphOS and Haiku. Started in 2008 as a fork of the racing car simulator TORCS, it is mainly written in C++ and released under GPL v2+ and Free Art License, the most recent release being version 2.3.0 of March 2023.
The development of an accurate driving behaviour, with different physics engines available, sets the project among the few open source racing simulation codebases.
can be played with a variety of input devices, including keyboards, mouses, joypads, joysticks, racing wheels and pedals.
Gameplay
Racing modes
features several different racing modes; while some offer greater customization than others, most generally try to reproduce real types of races. Complex events, such as various categories of championships or endurance races, are also available. Because racing modes are defined by plain-text configuration files, custom ones can be freely created. In this context the most relevant change since TORCS − introduced in 2.0 − is the "Career" mode: here the player can compete with different car classes, during multiple seasons, on randomly selected tracks and against balanced random opponents, earning points in championship rankings. Within practice mode, since version 1.4.0, it is possible to run robot races in the "results-only" mode, that is, ignoring the graphics display of the race; this allows the simulation to be run at a speed limited only by the computing power available, and is mostly used by robot developers. For the same purpose version 2.0 provides also a text-only mode: the race is run without graphics − no hardware acceleration being required − and the results are displayed through a command-line interface.
Weather
introduced the simulation of a real sky dome, along with customizable weather conditions: the user can choose the time of day, the cloud cover and the intensity of rainfall to have during the race. The sky dome can be set up as dynamic, namely simulating the succession of day and night and the movement of celestial bodies. Weather simulation affects both physics, with proper corrections to the cars' adherence, and graphics, with animated cloud layers, and if necessary a 2D overlay of rain particles.
Physics
can load different physics engines to use during races. Written in C++, they are software modules executed at every simulation frame to compute the cars' parameters such as position, speed, damage, collisions, suspensions. The user is able to select the physics engine before every race; currently available are:
All physics engines feature real-time car collisions based on the SOLID library. Each car model defines a bounding box according to which the physics engine detects side and bottom collisions; these produce car damages, computed on a scale ranging from 0 to 10000; damages affect only cars' performances, without producing any graphical output. A car with more than 10000 damage points is excluded from the race.
Sound
Sound management is achieved through OpenAL or, optionally, PLIB. Audible sounds include collision and tire screeching noise, in addition to the engine's; there are simulated also complex effects such as attenuation and Doppler shift. In 2011, the professional sound production company audioberlin reworked the default sounds; the improved versions are included in release 2.0.0.
Racing interfaces
While racing, the player is offered a customizable 2D cockpit displaying various gauges, lap times information and a dynamic mini-map. Every instrument features several modes, among which the player can choose while racing in order to change the appearance, or even completely hide the interface. A rear mirror is also available, although quite expensive in terms of consumed computing power. An "arcade" mode, legacy of TORCS, is still maintained as of version 2.0; according to the authors of the Italian manual for TORCS, it is more suitable for the novice player of . New addition to is the Formula One-style timer with an accuracy of a millisecond (ten times more precise than TORCS' one).
AI
TORCS was born with focus set more on AI racing than on human driving. , according to the project's description, shifted the balance towards a more user-oriented racing experience. Nonetheless, unlike the fate of the other legacy content, reworked but mostly maintained, in late 2009 all the robot engines inherited from TORCS were removed and replaced by new, more advanced ones.