Retained mode in computer graphics is a major pattern of API design in graphics libraries, in which * the

graphics library A graphics library is a program library designed to aid in rendering computer graphics to a monitor. This typically involves providing optimized versions of functions that handle common rendering tasks. This can be done purely in software and runn ...

, instead of the

client Client(s) or The Client may refer to: * Client (business) * Client (computing), hardware or software that accesses a remote service on another computer * Customer or client, a recipient of goods or services in return for monetary or other valuable ...

, retains the scene (complete

object model In computing, object model has two related but distinct meanings: # The properties of objects in general in a specific computer programming language, technology, notation or methodology that uses them. Examples are the object models of ''Java'', ...

of the

rendering primitive This is a glossary of terms relating to computer graphics. For more general computer hardware terms, see glossary of computer hardware terms. 0–9 A B ...

s) to be rendered and * the

calls into the

do not directly cause actual rendering, but make use of extensive indirection to resources, managed thus ''retained'' by the

. It does not preclude the use of

double-buffering In computer science, multiple buffering is the use of more than one buffer to hold a block of data, so that a "reader" will see a complete (though perhaps old) version of the data, rather than a partially updated version of the data being creat ...

. Immediate mode is an alternative approach. Historically, retained mode has been the dominant style in

GUI The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

libraries; however, both can coexist in the same library and are not necessarily exclusionary in practice.

Overview

In retained mode the

calls do not directly cause actual rendering, but instead update an abstract internal model (typically a list of objects) which is maintained within the library's data space. This allows the library to optimize when actual rendering takes place along with the processing of related objects. Some techniques to optimize rendering include: * managing

double buffering In computer science, multiple buffering is the use of more than one buffer to hold a block of data, so that a "reader" will see a complete (though perhaps old) version of the data, rather than a partially updated version of the data being creat ...

* treatment of hidden surfaces by backface culling/

occlusion culling In 3D computer graphics, hidden-surface determination (also known as shown-surface determination, hidden-surface removal (HSR), occlusion culling (OC) or visible-surface determination (VSD)) is the process of identifying what surfaces and parts o ...

(

Z-buffering A depth buffer, also known as a z-buffer, is a type of data buffer used in computer graphics to represent depth information of objects in 3D space from a particular perspective. Depth buffers are an aid to rendering a scene to ensure that the ...

) * only transferring data that has changed from one frame to the next from the application to the library Example of coexistence with immediate mode in the same library is

OpenGL OpenGL (Open Graphics Library) is a cross-language, cross-platform application programming interface (API) for rendering 2D and 3D vector graphics. The API is typically used to interact with a graphics processing unit (GPU), to achieve hardwa ...

. OpenGL has immediate mode functions that can use previously defined server side objects ( textures,

vertex buffer This is a glossary of terms relating to computer graphics. For more general computer hardware terms, see glossary of computer hardware terms. 0–9 A B ...

s and index buffers,

shader 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 spec ...

s, etc.) without resending unchanged data. Examples of retained mode rendering systems include

Windows Presentation Foundation Windows Presentation Foundation (WPF) is a free and open-source graphical subsystem (similar to WinForms) originally developed by Microsoft for rendering user interfaces in Windows-based applications. WPF, previously known as "Avalon", was initia ...

SceneKit SceneKit, sometimes rendered Scene Kit, is a 3D graphics application programming interface (API) for Apple Inc. platforms written in Objective-C. It is a high-level framework designed to provide an easy-to-use layer over the lower level APIs like O ...

on macOS, and

PHIGS PHIGS (Programmer's Hierarchical Interactive Graphics System) is an application programming interface (API) standard for rendering 3D computer graphics, considered to be the 3D graphics standard for the 1980s through the early 1990s. Subsequently, ...

References

{{DEFAULTSORT:Retained Mode Computer graphics 3D computer graphics

Overview

See also

References