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High-dynamic-range rendering (HDRR or HDR rendering), also known as high-dynamic-range lighting, is the rendering of computer graphics scenes by using lighting calculations done in a larger dynamic range. This allows preservation of details that may be lost due to limiting contrast ratios. Video games and computer-generated movies and special effects benefit from this as it creates more realistic scenes than with the more simplistic lighting models used. Graphics processor company Nvidia summarizes the motivation for HDRR in three points: bright things can be really bright, dark things can be really dark, and details can be seen in both. ==History== The use of high-dynamic-range imaging (HDRI) in computer graphics was introduced by Greg Ward in 1985 with his open-source Radiance rendering and ''lighting simulation'' software which created the first file format to retain a high-dynamic-range image. HDRI languished for more than a decade, held back by limited computing power, storage, and capture methods. Not until recently has the technology to put HDRI into practical use been developed.〔(【引用サイトリンク】title=High Dynamic Range Imaging )〕 In 1990, Nakame, et al., presented a lighting model for driving simulators that highlighted the need for high-dynamic-range processing in realistic simulations. In 1995, Greg Spencer presented ''Physically-based glare effects for digital images'' at SIGGRAPH, providing a quantitative model for flare and blooming in the human eye. In 1997 Paul Debevec presented ''Recovering high dynamic range radiance maps from photographs'' at SIGGRAPH and the following year presented ''Rendering synthetic objects into real scenes''. These two papers laid the framework for creating HDR ''light probes'' of a location and then using this probe to light a rendered scene. HDRI and HDRL (high-dynamic-range image-based lighting) have, ever since, been used in many situations in 3D scenes in which inserting a 3D object into a real environment requires the lightprobe data to provide realistic lighting solutions. In gaming applications, Riven: The Sequel to Myst in 1997 used an HDRI postprocessing shader directly based on Spencer's paper. After E³ 2003, Valve Software released a demo movie of their Source engine rendering a cityscape in a high dynamic range.〔 〕 The term was not commonly used again until E³ 2004, where it gained much more attention when Valve Software announced ''Half-Life 2: Lost Coast'' and Epic Games showcased Unreal Engine 3, coupled with open-source engines such as OGRE 3D and open-source games like ''Nexuiz''. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「High-dynamic-range rendering」の詳細全文を読む スポンサード リンク
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