03-09-2012, 02:48 PM
OpenGL
1OpenG.ppt (Size: 287 KB / Downloads: 62)
Early History of APIs
1973 formed two committees to come up with a standard graphics API
Graphical Kernel System (GKS)
2D but contained good workstation model
Core
Both 2D and 3D
GKS adopted as IS0 and later ANSI standard (1980s)
GKS not easily extended to 3D (GKS-3D)
Far behind hardware development
PHIGS and X
Programmers Hierarchical Graphics System (PHIGS)
Arose from CAD community
Database model with retained graphics (structures)
X Window System
DEC/MIT effort
Client-server architecture with graphics
PEX combined the two
Not easy to use (all the defects of each)
SGI and GL
Silicon Graphics (SGI) revolutionized the graphics workstation by implementing the pipeline in hardware (1982)
To access the system, application programmers used a library called GL
With GL, it was relatively simple to program three dimensional interactive applications
OpenGL
The success of GL lead to OpenGL (1992), a platform-independent API that was
Easy to use
Close enough to the hardware to get excellent performance
Focus on rendering
Omitted windowing and input to avoid window system dependencies
OpenGL Evolution
Controlled by an Architectural Review Board (ARB)
Members include SGI, Microsoft, Nvidia, HP, 3DLabs, IBM,…….
Relatively stable (present version 2.0)
Evolution reflects new hardware capabilities
3D texture mapping and texture objects
Vertex programs
Allows for platform specific features through extensions
OpenGL Libraries
OpenGL core library
OpenGL32 on Windows
GL on most unix/linux systems (libGL.a)
OpenGL Utility Library (GLU)
Provides functionality in OpenGL core but avoids having to rewrite code
Links with window system
GLX for X window systems
WGL for Windows
AGL for Macintosh
1OpenG.ppt (Size: 287 KB / Downloads: 62)
Early History of APIs
1973 formed two committees to come up with a standard graphics API
Graphical Kernel System (GKS)
2D but contained good workstation model
Core
Both 2D and 3D
GKS adopted as IS0 and later ANSI standard (1980s)
GKS not easily extended to 3D (GKS-3D)
Far behind hardware development
PHIGS and X
Programmers Hierarchical Graphics System (PHIGS)
Arose from CAD community
Database model with retained graphics (structures)
X Window System
DEC/MIT effort
Client-server architecture with graphics
PEX combined the two
Not easy to use (all the defects of each)
SGI and GL
Silicon Graphics (SGI) revolutionized the graphics workstation by implementing the pipeline in hardware (1982)
To access the system, application programmers used a library called GL
With GL, it was relatively simple to program three dimensional interactive applications
OpenGL
The success of GL lead to OpenGL (1992), a platform-independent API that was
Easy to use
Close enough to the hardware to get excellent performance
Focus on rendering
Omitted windowing and input to avoid window system dependencies
OpenGL Evolution
Controlled by an Architectural Review Board (ARB)
Members include SGI, Microsoft, Nvidia, HP, 3DLabs, IBM,…….
Relatively stable (present version 2.0)
Evolution reflects new hardware capabilities
3D texture mapping and texture objects
Vertex programs
Allows for platform specific features through extensions
OpenGL Libraries
OpenGL core library
OpenGL32 on Windows
GL on most unix/linux systems (libGL.a)
OpenGL Utility Library (GLU)
Provides functionality in OpenGL core but avoids having to rewrite code
Links with window system
GLX for X window systems
WGL for Windows
AGL for Macintosh