|
PHIGS is an API standard for rendering 3D computer graphics, at one time considered to be the 3D graphics standard for the 1990s. Instead a combination of features and power led to the rise of OpenGL, which remains the de facto 3D standard to this day. API redirects here. ...
Computer graphics (CG) is the field of visual computing, where one utilizes computers both to generate visual images synthetically and to integrate or alter visual and spatial information sampled from the real world. ...
OpenGL (Open Graphics Library) is a specification defining a cross-language cross-platform API for writing applications that produce 3D computer graphics (and 2D computer graphics as well). ...
PHIGS is an acronym for Programmer's Hierarchical Interactive Graphics System, the word "hierarchical" referring to one of the more notable features of PHIGS. Unlike most graphics systems, PHIGS included a scene graph system as a part of the basic standard. Models were built up in a Central Structure Store (CSS), a database containing a "world" including both the drawing primitives and their attributes (color, line style, etc.). CSSes could be shared among a number of views, known under PHIGS as a workstation. Acronyms and initialisms are abbreviations formed from the initial letter or letters of words, such as NATO and XHTML, and are pronounced in a way that is distinct from the full pronunciation of what the letters stand for. ...
A scene graph (also called a scenegraph) is a general data structure commonly used by vector-based graphics editing applications. ...
PHIGS was almost always used with the X Windows system, supported via PEX, the "PHIGS Extension to X". PEX consisted of an add-on to the X Windows system, adding commands that would be forwarded from the X Windows server to the PEX system for rendering. Workstations were placed in windows typically, but could also be forwarded to take over the whole screen, or to various printer-output devices. In computing, the X Window System (commonly X11 or X) is a windowing system for bitmap displays. ...
Displaying graphics on the screen in PHIGS was a three-step process; first the model would be built into a CSS, then a workstation would be created and opened, and finally the model would be connected to the workstation. At that point the workstation would immediately render the model, and any future changes made to the model would instantly be reflected in the workstation view.
In comparison, OpenGL is an immediate-mode rendering system with no "state"; once an object is sent to a view to be rendered it essentially disappears. Changes to the model have to be re-sent into the system and re-rendered, dramatically increasing programmer workload. For simple projects, PHIGS was considerably easier to use and work with. On the other hand, OpenGL's "low-level" API allowed the programmer to make dramatic improvements in rendering performance by first examining the data on the CPU-side before trying to send it over the bus to the graphics engine. For instance, the programmer could "cull" the objects by examining which objects were actually visible in the scene, and sending only those objects that would actually end up on the screen. This was kept private in PHIGS, making it much more difficult to tune performance. Given the low performance systems of the era and the need for high-performance rendering, OpenGL was generally considered to be much more "powerful" for 3D programming. The central processing unit (CPU) is the part of a computer that interprets and carries out the instructions contained in the software. ...
PHIGS was designed in the 1980s and became an ANSI, and then ISO standard by 1989. Due to its early gestation, the standard supports only the most basic 3D graphics, including basic geometry and meshes, and only the basic Gouraud, "Dot", and Phong shading for rendering scenes. Features considered "standard" today, notably texture mapping, were not supported, nor were many machines of the era physically capable of it (at least in realtime). The American National Standards Institute (ANSI) is a private, non-profit standards organization that produces industrial standards in the United States. ...
In other languages Iso means the following in other languages: Big in Finnish a Latin transliteration of the Greek ίσος, meaning equal. ...
Spherical texture mapping Texture mapping is a method of adding realism to a computer-generated graphic. ...
PHIGS originally lacked the capability to render illuminated scenes, and was superseded by PHIGS+. PHIGS+ works in essentially the same manner, but added methods for lighting a 3D scene, and was often referred to as PHIGS PLUS (where the PLUS was a slightly tongue-in-cheek acronym for "Plus Lumière Und Shading"). PHIGS+ also introduced more advanced graphics primitives, such as NURBS surfaces. NURBS, short for nonuniform rational B-spline, is a computer graphics technique for drawing curves. ...
External links
-
- Actually PHIGS+
|
Feeds |
Contact