as the widespread GeForce 2 and Radeon 7200, as well as DirectX 6.0 chipsets such as RIVA TNT2 and Rage 128, and integrated on-board graphics accelerators. Until this generation of games, a powerful CPU was able to somewhat compensate for an older video card. Average Video Hardware requirements: minimum was a GeForce 3 or Radeon 8500, strongly recommended was the GeForce FX, Radeon 9700 (or other cards with Pixel shader 2.x support). The Radeon 9700 demonstrated that anti-aliasing (AA) and/or anisotropic filtering (AF) could be fully usable options, even in the newest and most demanding titles at the time, and resulted in the widespread acceptance of AA and AF as standard features. AA and AF had been supported by many earlier graphics chips prior to this but carried a heavy performance hit and so most gamers opted not to enable these features. With these new technologies game engines featured seamlessly integrated indoor/outdoor environments, used shaders for more realistic animations (characters, water, weather effects, etc.), and generally increased realism. The fact that the GPU performed some of the tasks that were already done by the CPU, and more generally the increasing processing power available, allowed to add realistic physics effects to the games, for example with the inclusion of the Havok physics engine in most video games. Physics had been already added in a video game in 1998 with Jurassic Park: Trespasser, but limited hardware capabilities at the time, and the absence of a middleware like Havok to handle physics had made it a technical and commercial failure. id Tech 4, first used for Doom 3 (2004), used an entirely dynamic per-pixel lighting, whereas previously, 3D engines had relied primarily on pre-calculated per-vertex lighting or lightmaps and Gouraud shading. The Shadow volume approach used in Doom 3 permitted more realistic lighting and shadows, however this came at a price as it could not render soft shadows, and the engine was primarily good indoors. Later this was rectified to work with vast outdoor spaces, with the introduction of MegaTexture technology in the id Tech 4 engine. The same year, Valve released Half-Life 2, powered by their new Source engine. This new engine was notable in that, among other things, it had very realistic facial animations for NPCs, including what was described as an impressive lip-syncing technology. Late 2000s: The approach to Photorealism Further improvements in GPUs like Shader Model 3 and Shader