Professional game development usually begins with a game design, which itself has several possible origins. Occasionally the game development process starts with no clear design in mind, but as a series of experiments. For example, game designer Will Wright began development of The Sims by getting programmers to experiment with several ideas.
Programmers are often required to produce prototypes of gameplay ideas and features. A great deal of prototyping may take place during pre-production, before the design document is complete, and may help determine what features the design specifies.
Prototypes are developed quickly with very little time for up-front design and mostly act as a proof of concept or to test ideas. They are not expected to work flawlessly, but are developed to try out new, sometimes exotic, ideas.
Though the programmer's main job is not to develop the game design, the programmers often contribute to the design, as do game artists. The game designer will solicit input from both the producer and the art and programming lead for ideas and strategies for the game design. Often individuals in non-lead positions also contribute, such as copywriters and other programmers and artists.
Programmers often closely follow the game design document. As the game development progresses, the design document changes as programming limitations and new capabilities are discovered and exploited.
During production, programmers may create a great deal of source code to create the game described in the game's design document. Along the way, the design document is modified to meet limitations or expanded to exploit new features. The design document is very much a "living document", much of whose life is dictated by programmer's schedules, talent and resourcefulness.
While many programmers have some say in a game's content, most game producers solicit input from the lead programmer as to the status of a game programming development. The lead is responsible for knowing the status of all facets of the game's programming and for pointing out limitations. The lead programmer may also pass on suggestions from the programmers as to possible features they'd like to implement.
With today's visually rich content, the programmer must often interact with the art staff. This very much depends on the programmer's role, of course. For example, a 3D graphics programmer may need to work side by side with the game's 3D modelers discussing strategies and design considerations, while an AI programmer may need to interact very little, if at all, with the art staff. To help artists and level designers with their tasks, programmers may volunteer or be called upon to develop tools and utilities. Many of these may be for a specific purpose and can be buggy due to time constraints (time for development of such tools is often not included in a game's schedule) as well as because they are only for in-house use anyway. Many game tools are developed in RAD languages for quicker development and may be discarded after the completion of the game.
The formal quality assurance testing process, performed by professional game testers, begins well into game development. High-budget titles may begin testing with the first playable alpha, while low-budget and casual games might not enter testing until a release candidate is ready. The programmers' task is to fix errors and bugs as such are discovered by the QA teams.
Final tasks include "polishing" the game, such as programmers fixing occasional bugs—from minor to catastrophic—that may arise during the last phases of testing.
Game developers may have a beta testing period, but the definition of such varies from developer to developer. Often a beta contains all of the game's features, but may have a few bugs or incomplete content. Few games are given a public beta period, for example, to measure stress tolerance for game servers.
When the game is deemed complete, it is said to have "gone gold" and is shipped off to the publisher. Depending on circumstances, the publisher may then subject it to its own quality assurance or may begin pressing the game from the gold master.
Once a game ships, the maintenance phase for the video game begins. Programmers wait for a period to get as many bug reports as possible. Once the developer thinks they've obtained enough feedback, the programmers start working on a patch. The patch may take weeks or months to develop, but it's intended to fix most bugs and problems with the game. Occasionally a patch may include extra features or content or may even alter gameplay.
Most modern games take from one to three years to complete. The length of development depends on a number of factors, but programming is required throughout all phases of development except the very early stages of game design.