Changes between Initial Version and Version 1 of opengl-intro


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Timestamp:
Jun 26, 2013, 6:31:20 PM (11 years ago)
Author:
leon
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  • opengl-intro

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     1= Visualization with OpenGL =
     2Essential approaches to programming computer graphics with Open Graphics
     3Language (OpenGL) graphics library are described. This document serves as
     4the basis for exercises in PRACE Summer of HPC Visualization training.
     5Rationale for giving introduction to OpenGL is that such knowledge is
     6important when developing codes that require some specific visualization
     7for which OpenGL can be handy. Programming Graphical Processing Unit
     8(GPU) through ''shaders'' is an important technique to accelerate
     9graphics and other embarrassing parallel problems. OpenGL evolved from
     10immediate mode to GPU only processing with the advent of OpenGL Shading
     11Language (GLSL). Introduction to the subject is given by recipes to
     12follow, discussing important techniques for visualization that can also
     13be extended to general GPU programming for parallel computing. Instead of
     14jumping to the latest OpenGL specification we use minimum required OpenGL
     152.1 with the extensions currently available on modest hardware and still
     16be able to use modern OpenGL 3.1+ programming principles.
     17
     18
     19== Introduction ==
     20For the visualization of specific phenomena is usually not possible to use
     21a general purpose visualization tools. Such cases occur especially in the
     22visualization of engineering and physics problems. The modeling results are
     23usually not only simple function plots but complex objects such as graphs,
     24hierarchical structure, animation, motion mechanism, control channels,
     25volume models of specific forms, ...
     26
     27Through the time different standards were effective for computer graphics.
     28This is mainly due to the complexity of implementation and closed code in
     29the past. OpenGL remains the only widely accepted open standard, which was
     30first introduced on Silicon Graphics workstations (SGI). There exist also a
     31Microsoft Direct3D, which is limited to PCs with Windows and is not as easy
     32to use as OpenGL, which is due to its openness and capacity provided on all
     33operating systems and hardware platforms. OpenGL stagnated for some time
     34with upgrades to the original SGI specification. Many extensions previously
     35available from hardware vendors are now standardized with OpenGL 3+ where
     36things dramatically changed. ''Immediate mode'' programming where
     37communication from OS to GPU was regular practice and major obstacle to
     38graphics performance. Programming knowledge of OpenGL 1.x is therefore not
     39recommended for nowadays and can simply be forgotten and treated as legacy.