Computer Graphics - The Graphics Pipeline by anamaulida

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									In 3D computer graphics the terms graphics pipeline or rendering pipeline
refers generally to the latest method of rasterization rendering which is
supported by graphics hardware. On the input side of the pipeline is fed
a three-dimensional representation of a scene for instance a battle scene
of a computer game. This three-dimensional input is then processed so
that the output is a 2D raster image of the three-dimensional input.
OpenGL and Direct3D are two well known rendering models.EfficiencyAll
vertices and fragments are independent. This makes the graphics pipeline
well suited to the rendering process. It allows the GPU to function as a
stream processor. Further all stages of the pipeline can be used at the
same time for different vertices or fragments. Graphics processors can
due to the independence of the vertices and fragments make use of
parallel processing units to process multiple vertices or fragments in a
single stage of the pipeline at the same time (1).The Graphics
PipelineThe typical pipeline has the following stages:
Bus interface or front end - used to send and receive data and commands.
 Vertex processing - converts each vertex to a 2D screen position.
 Clipping - removes parts of the image not visible on the screen such the
back of buildings.
 Primitive assembly, triangle setup - vertices are collected and
converted into triangles.
 Rasterization - the triangles are filled with pixels known as fragments.
Fragments may end up in the frame buffer if there is change or if not
hidden.
 Occlusion - pixels that are hidden are removed.
 Parameter interpolation - the values for each pixel that were rasterized
are computed, based on colour, fog and texture.
 Pixel shader - texture and final colours are added to the fragments.
 Pixel engine - mathematically combine the final colour, its coverage and
transparency. Output is a depth value for the pixel.
 Frame buffer controller - interfaces to the memory used to hold the
actual pixel values as displayed on screen (2).
References
Wikipedia, the free encyclopedia. (2005, August 16). Graphics pipeline.
Retrieved 2009 November 2009 from the Wikipedia website
http://en.wikipedia.org/wiki/Graphics_pipeline
 Answers.com. (undated). graphics pipeline. Retrieved 2009 November 22
from Answers.com website at http://www.answers.com/topic/graphics-
pipeline-technology

								
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