Glide emulator development started in the late 1990s. Before 3dfx ended, the company tried very hard to stop these attempts, ending early emulation projects using legal threats. However, a short amount of time before it ended and Nvidia bought its assets, 3dfx made the Glide API, and also the Voodoo 2 and Voodoo 3 specifications, open source, which later became an open source project. No games released after 1999 only support Glide for 3D acceleration (Direct3D and OpenGL are used instead), but Glide emulation is still needed to run older games with hardware acceleration. Because the specifications and code are now open source, multiple emulators and wrappers are available that allow older games that use the Glide API to run on non-Voodoo hardware. Other projects, such as Glidos, allow even older games to use Glide.