Per-pixel lighting

In <a href="/facts/Computer_graphics/lapBE8wv">computer graphics</a>, per-<a href="/facts/Pixel/UzwBvXBV">pixel</a> lighting refers to any technique for <a href="/facts/Computer_graphics_lighting/kHshvyKY">lighting</a> an image or scene that calculates <a href="/facts/Illumination_(image)/rxqFN6Dm">illumination</a> for each pixel on a rendered image. This is in contrast to other popular methods of lighting such as <a href="/facts/Gouraud_shading/04Nz96F5">vertex lighting</a>, which calculates illumination at each <a href="/facts/Vertex_(computer_graphics)/lj0ltT3g">vertex</a> of a <a href="/facts/3D_model/6V3Ry9AJ">3D model</a> and then <a href="/facts/Interpolation/8PyetX4f">interpolates</a> the resulting values over the model's faces to calculate the final per-pixel color values.
Per-pixel lighting is commonly used with techniques, such as <a href="/facts/Blend_modes/8lK8znNX">blending</a>, <a href="/facts/Alpha_blending/7uUBtjrt">alpha blending</a>, <a href="/facts/Alpha_to_coverage/kc25X3g8">alpha to coverage</a>, <a href="/facts/Anti-aliasing/m3Ew0TQ6">anti-aliasing</a>, <a href="/facts/Texture_filtering/XraFoapy">texture filtering</a>, <a href="/facts/Clipping_(computer_graphics)/xpPsC6Ax">clipping</a>, <a href="/facts/Hidden-surface_determination/hk9dqmDE">hidden-surface determination</a>, <a href="/facts/Z-buffering/HTyzcKbx">Z-buffering</a>, <a href="/facts/Stencil_buffer/BNGPjMJE">stencil buffering</a>, <a href="/facts/Shading/ewcDEfda">shading</a>, <a href="/facts/Mipmapping/z0alvP6k">mipmapping</a>, <a href="/facts/Normal_mapping/7YmzxkPp">normal mapping</a>, <a href="/facts/Bump_mapping/c97rLmK6">bump mapping</a>, <a href="/facts/Displacement_mapping/RPxgu1Fn">displacement mapping</a>, <a href="/facts/Parallax_mapping/9mztrTcu">parallax mapping</a>, <a href="/facts/Shadow_mapping/vIy5GAEq">shadow mapping</a>, <a href="/facts/Specular_mapping/KAUEvtnd">specular mapping</a>, <a href="/facts/Shadow_volume/usGAIQ2d">shadow volumes</a>, <a href="/facts/High-dynamic-range_rendering/loVJkaGN">high-dynamic-range rendering</a>, <a href="/facts/Ambient_occlusion/oeEEyb2x">ambient occlusion</a> (<a href="/facts/Screen_space_ambient_occlusion/P3GgkMXf">screen space ambient occlusion</a>, <a href="/facts/Screen_space_directional_occlusion/BYclGk4n">screen space directional occlusion</a>, <a href="/facts/Ray-traced_ambient_occlusion/04lhn2hR">ray-traced ambient occlusion</a>), <a href="/facts/Ray_tracing_(graphics)/n6qpap2q">ray tracing</a>, <a href="/facts/Global_illumination/CbQX6CWM">global illumination</a>, and <a href="/facts/Tessellation_(computer_graphics)/xorfyI4q">tessellation</a>. Each of these techniques provides some additional data about the surface being lit or the scene and light sources that contributes to the final look and feel of the surface.
Most modern video game engines implement lighting using per-pixel techniques instead of vertex lighting to achieve increased detail and realism. The <a href="/facts/Id_Tech_4/HdnYQ2pP">id Tech 4</a> engine, used to develop such games as <a href="/facts/Brink_(video_game)/DHMaD3Wg">Brink</a> and <a href="/facts/Doom_3/np3bfurA">Doom 3</a>, was one of the first game engines to implement a completely per-pixel shading engine. All versions of the <a href="/facts/CryENGINE/jbgUIbGr">CryENGINE</a>, <a href="/facts/Frostbite_Engine/Bg5q9tce">Frostbite Engine</a>, and <a href="/facts/Unreal_Engine/0ghxRQl8">Unreal Engine</a>, among others, also implement per-pixel shading techniques.
<a href="/facts/Deferred_shading/qq8LNRCc">Deferred shading</a> is a recent development in per-pixel lighting notable for its use in the Frostbite Engine and <a href="/facts/Battlefield_3/me7pNeP8">Battlefield 3</a>. Deferred shading techniques are capable of rendering potentially large numbers of small lights inexpensively (other per-pixel lighting approaches require full-screen calculations for each light in a scene, regardless of size).

Per-pixel lighting open-in-new

Per-pixel lighting