See also
- Deferred Shading, a shading process that relies heavily on MRT to perform in real-time
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In the field of 3D computer graphics, Multiple Render Targets, or MRT, is a feature of modern graphics processing units (GPUs) that allows the programmable rendering pipeline to render images to multiple render target textures at once. These textures can then be used as inputs to other shaders or as texture maps applied to 3D models. Introduced by OpenGL 2.0 and Direct3D 9, MRT can be invaluable to real-time 3D applications such as video games. Before the advent of MRT, a programmer would have to issue a command to the GPU to draw the 3D scene once for each render target texture, resulting in redundant vertex transformations which, in a real-time program expected to run as fast as possible, can be quite time-consuming. With MRT, a programmer creates a pixel shader that returns an output value for each render target. This pixel shader then renders to all render targets with a single draw command.
A common use of MRT is deferred shading, a shading process which, unlike forward shading, performs lighting calculations on an entire 3D scene at once instead of on each individual object. To do this in real-time, MRT is used to store the required information for the lighting calculations in multiple render targets, which are then used after the entire scene has been drawn to calculate the lit final image. Typically one render target holds color and surface information of objects, while another contains the surface normals and depth information of the scene which are used to calculate the reflection of light. Additional render targets can be used to store information such as the specularity of the surface and ambient occlusion data.
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Rendering or image synthesis is the process of generating a photorealistic or non-photorealistic image from a 2D or 3D model by means of a computer program. The resulting image is referred to as the render. Multiple models can be defined in a scene file containing objects in a strictly defined language or data structure. The scene file contains geometry, viewpoint, texture, lighting, and shading information describing the virtual scene. The data contained in the scene file is then passed to a rendering program to be processed and output to a digital image or raster graphics image file. The term "rendering" is analogous to the concept of an artist's impression of a scene. The term "rendering" is also used to describe the process of calculating effects in a video editing program to produce the final video output.
Gouraud shading, named after Henri Gouraud, is an interpolation method used in computer graphics to produce continuous shading of surfaces represented by polygon meshes. In practice, Gouraud shading is most often used to achieve continuous lighting on triangle meshes by computing the lighting at the corners of each triangle and linearly interpolating the resulting colours for each pixel covered by the triangle. Gouraud first published the technique in 1971.
The RenderMan Interface Specification, or RISpec in short, is an open API developed by Pixar Animation Studios to describe three-dimensional scenes and turn them into digital photorealistic images. It includes the RenderMan Shading Language.
Texture mapping is a method for mapping a texture on a computer-generated graphic. Texture here can be high frequency detail, surface texture, or color.
Shading refers to the depiction of depth perception in 3D models or illustrations by varying the level of darkness. Shading tries to approximate local behavior of light on the object's surface and is not to be confused with techniques of adding shadows, such as shadow mapping or shadow volumes, which fall under global behavior of light.
In scientific visualization and computer graphics, volume rendering is a set of techniques used to display a 2D projection of a 3D discretely sampled data set, typically a 3D scalar field.
In computer graphics, a shader is a computer program that calculates the appropriate levels of light, darkness, and color during the rendering of a 3D scene—a process known as shading. Shaders have evolved to perform a variety of specialized functions in computer graphics special effects and video post-processing, as well as general-purpose computing on graphics processing units.
A lightmap is a data structure used in lightmapping, a form of surface caching in which the brightness of surfaces in a virtual scene is pre-calculated and stored in texture maps for later use. Lightmaps are most commonly applied to static objects in applications that use real-time 3D computer graphics, such as video games, in order to provide lighting effects such as global illumination at a relatively low computational cost.
A shading language is a graphics programming language adapted to programming shader effects. Shading languages usually consist of special data types like "vector", "matrix", "color" and "normal".
Subsurface scattering (SSS), also known as subsurface light transport (SSLT), is a mechanism of light transport in which light that penetrates the surface of a translucent object is scattered by interacting with the material and exits the surface at a different point. The light will generally penetrate the surface and be reflected a number of times at irregular angles inside the material before passing back out of the material at a different angle than it would have had if it had been reflected directly off the surface. Subsurface scattering is important for realistic 3D computer graphics, being necessary for the rendering of materials such as marble, skin, leaves, wax and milk. If subsurface scattering is not implemented, the material may look unnatural, like plastic or metal.
In computer graphics, per-pixel lighting refers to any technique for lighting an image or scene that calculates illumination for each pixel on a rendered image. This is in contrast to other popular methods of lighting such as vertex lighting, which calculates illumination at each vertex of a 3D model and then interpolates the resulting values over the model's faces to calculate the final per-pixel color values.
3D rendering is the 3D computer graphics process of converting 3D models into 2D images on a computer. 3D renders may include photorealistic effects or non-photorealistic styles.
In computer graphics, a texture mapping unit (TMU) is a component in modern graphics processing units (GPUs). They are able to rotate, resize, and distort a bitmap image to be placed onto an arbitrary plane of a given 3D model as a texture, in a process called texture mapping. In modern graphics cards it is implemented as a discrete stage in a graphics pipeline, whereas when first introduced it was implemented as a separate processor, e.g. as seen on the Voodoo2 graphics card.
Multisample anti-aliasing (MSAA) is a type of spatial anti-aliasing, a technique used in computer graphics to remove jaggies.
Computer graphics lighting is the collection of techniques used to simulate light in computer graphics scenes. While lighting techniques offer flexibility in the level of detail and functionality available, they also operate at different levels of computational demand and complexity. Graphics artists can choose from a variety of light sources, models, shading techniques, and effects to suit the needs of each application.
Terrain cartography or relief mapping is the depiction of the shape of the surface of the Earth on a map, using one or more of several techniques that have been developed. Terrain or relief is an essential aspect of physical geography, and as such its portrayal presents a central problem in cartographic design, and more recently geographic information systems and geovisualization.
In the field of 3D computer graphics, deferred shading is a screen-space shading technique that is performed on a second rendering pass, after the vertex and pixel shaders are rendered. It was first suggested by Michael Deering in 1988.
Computer graphics deals with generating images and art with the aid of computers. Today, computer graphics is a core technology in digital photography, film, video games, digital art, cell phone and computer displays, and many specialized applications. A great deal of specialized hardware and software has been developed, with the displays of most devices being driven by computer graphics hardware. It is a vast and recently developed area of computer science. The phrase was coined in 1960 by computer graphics researchers Verne Hudson and William Fetter of Boeing. It is often abbreviated as CG, or typically in the context of film as computer generated imagery (CGI). The non-artistic aspects of computer graphics are the subject of computer science research.
PICA200 is a graphics processing unit (GPU) designed by Digital Media Professionals Inc. (DMP), a Japanese GPU design startup company, for use in embedded devices such as vehicle systems, mobile phones, cameras, and game consoles. The PICA200 is an IP Core which can be licensed to other companies to incorporate into their SOCs. It was most notably licensed for use in the Nintendo 3DS.
This is a glossary of terms relating to computer graphics.