3D graphics eBook - Course Materials Repository
3D graphics eBook - Course Materials Repository 3D graphics eBook - Course Materials Repository
Fragment 45 Fragment In computer graphics, a fragment is the data necessary to generate a single pixel's worth of a drawing primitive in the frame buffer. This data may include, but is not limited to: • raster position • depth • interpolated attributes (color, texture coordinates, etc.) • stencil • alpha • window ID As a scene is drawn, drawing primitives (the basic elements of graphics output, such as points,lines, circles, text etc [1] ) are rasterized into fragments which are textured and combined with the existing frame buffer. How a fragment is combined with the data already in the frame buffer depends on various settings. In a typical case, a fragment may be discarded if it is farther away than the pixel that is already at that location (according to the depth buffer). If it is nearer than the existing pixel, it may replace what is already there, or, if alpha blending is in use, the pixel's color may be replaced with a mixture of the fragment's color and the pixel's existing color, as in the case of drawing a translucent object. In general, a fragment can be thought of as the data needed to shade the pixel, plus the data needed to test whether the fragment survives to become a pixel (depth, alpha, stencil, scissor, window ID, etc.) References [1] The Drawing Primitives by Janne Saarela (http:/ / baikalweb. jinr. ru/ doc/ cern_doc/ asdoc/ gks_html3/ node28. html)
Geometry pipelines 46 Geometry pipelines Geometric manipulation of modeling primitives, such as that performed by a geometry pipeline, is the first stage in computer graphics systems which perform image generation based on geometric models. While Geometry Pipelines were originally implemented in software, they have become highly amenable to hardware implementation, particularly since the advent of very-large-scale integration (VLSI) in the early 1980s. A device called the Geometry Engine developed by Jim Clark and Marc Hannah at Stanford University in about 1981 was the watershed for what has since become an increasingly commoditized function in contemporary image-synthetic raster display systems. [1] [2] Geometric transformations are applied to the vertices of polygons, or other geometric objects used as modelling primitives, as part of the first stage in a classical geometry-based graphic image rendering pipeline. Geometric computations may also be applied to transform polygon or patch surface normals, and then to perform the lighting and shading computations used in their subsequent rendering. History Hardware implementations of the geometry pipeline were introduced in the early Evans & Sutherland Picture System, but perhaps received broader recognition when later applied in the broad range of graphics systems products introduced by Silicon Graphics (SGI). Initially the SGI geometry hardware performed simple model space to screen space viewing transformations with all the lighting and shading handled by a separate hardware implementation stage, but in later, much higher performance applications such as the RealityEngine, they began to be applied to perform part of the rendering support as well. More recently, perhaps dating from the late 1990s, the hardware support required to perform the manipulation and rendering of quite complex scenes has become accessible to the consumer market. Companies such as NVIDIA and ATI (now a part of AMD) are two current leading representatives of hardware vendors in this space. The GeForce line of graphics cards from NVIDIA were the first to implement hardware geometry processing in the consumer PC market, while earlier graphics accelerators by 3Dfx and others had to rely on the CPU to perform geometry processing. This subject matter is part of the technical foundation for modern computer graphics, and is a comprehensive topic taught at both the undergraduate and graduate levels as part of a computer science education. References [1] Clark, James (July 1980). "Special Feature A VLSI Geometry Processor For Graphics" (http:/ / www. computer. org/ portal/ web/ csdl/ doi/ 10. 1109/ MC. 1980. 1653711). Computer: pp. 59–68. . [2] Clark, James (July 1982). "The Geometry Engine: A VLSI Geometry System for Graphics" (http:/ / accad. osu. edu/ ~waynec/ history/ PDFs/ geometry-engine. pdf). Proceedings of the 9th annual conference on Computer graphics and interactive techniques. pp. 127-133. .
- Page 1 and 2: 3D Rendering PDF generated using th
- Page 3 and 4: Image-based lighting 64 Image plane
- Page 5 and 6: References Article Sources and Cont
- Page 7 and 8: 3D rendering 2 Non real-time Animat
- Page 9 and 10: 3D rendering 4 The shaded three-dim
- Page 11 and 12: Ambient occlusion 6 ambient occlusi
- Page 13 and 14: Ambient occlusion 8 • ShadeVis (h
- Page 15 and 16: Anisotropic filtering 10 will only
- Page 17 and 18: Beam tracing 12 Beam tracing Beam t
- Page 19 and 20: Bilinear filtering 14 Are all true.
- Page 21 and 22: Binary space partitioning 16 togeth
- Page 23 and 24: Binary space partitioning 18 Other
- Page 25 and 26: Binary space partitioning 20 [1] Bi
- Page 27 and 28: Bounding interval hierarchy 22 Prop
- Page 29 and 30: Bounding volume 24 bounding boxes b
- Page 31 and 32: Bump mapping 26 Bump mapping Bump m
- Page 33 and 34: CatmullClark subdivision surface 28
- Page 35 and 36: CatmullClark subdivision surface 30
- Page 37 and 38: Conversion between quaternions and
- Page 39 and 40: Cube mapping 34 Advantages Cube map
- Page 41 and 42: Cube mapping 36 Related A large set
- Page 43 and 44: Diffuse reflection 38 2), or, of co
- Page 45 and 46: Displacement mapping 40 Meaning of
- Page 47 and 48: DooSabin subdivision surface 42 Ext
- Page 49: False radiosity 44 False radiosity
- Page 53 and 54: Global illumination 48 Rendering wi
- Page 55 and 56: Gouraud shading 50 Gouraud shading
- Page 57 and 58: Graphics pipeline 52 Graphics pipel
- Page 59 and 60: Graphics pipeline 54 References 1.
- Page 61 and 62: Hidden surface determination 56 imp
- Page 63 and 64: High dynamic range rendering 58 Hig
- Page 65 and 66: High dynamic range rendering 60 Ton
- Page 67 and 68: High dynamic range rendering 62 Fro
- Page 69 and 70: High dynamic range rendering 64 •
- Page 71 and 72: Irregular Z-buffer 66 Applications
- Page 73 and 74: Lambert's cosine law 68 than would
- Page 75 and 76: Lambertian reflectance 70 Lambertia
- Page 77 and 78: Level of detail 72 Well known appro
- Page 79 and 80: Level of detail 74 Hierarchical LOD
- Page 81 and 82: Newell's algorithm 76 Newell's algo
- Page 83 and 84: Non-uniform rational B-spline 78 Us
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- Page 87 and 88: Non-uniform rational B-spline 82 ar
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- Page 91 and 92: Normal mapping 86 How it works To c
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- Page 95 and 96: OrenNayar reflectance model 90 , ,
- Page 97 and 98: Painter's algorithm 92 The algorith
- Page 99 and 100: Parallax mapping 94 • Parallax Ma
Fragment 45<br />
Fragment<br />
In computer <strong>graphics</strong>, a fragment is the data necessary to generate a single pixel's worth of a drawing primitive in<br />
the frame buffer.<br />
This data may include, but is not limited to:<br />
• raster position<br />
• depth<br />
• interpolated attributes (color, texture coordinates, etc.)<br />
• stencil<br />
• alpha<br />
• window ID<br />
As a scene is drawn, drawing primitives (the basic elements of <strong>graphics</strong> output, such as points,lines, circles, text etc<br />
[1] ) are rasterized into fragments which are textured and combined with the existing frame buffer. How a fragment is<br />
combined with the data already in the frame buffer depends on various settings. In a typical case, a fragment may be<br />
discarded if it is farther away than the pixel that is already at that location (according to the depth buffer). If it is<br />
nearer than the existing pixel, it may replace what is already there, or, if alpha blending is in use, the pixel's color<br />
may be replaced with a mixture of the fragment's color and the pixel's existing color, as in the case of drawing a<br />
translucent object.<br />
In general, a fragment can be thought of as the data needed to shade the pixel, plus the data needed to test whether<br />
the fragment survives to become a pixel (depth, alpha, stencil, scissor, window ID, etc.)<br />
References<br />
[1] The Drawing Primitives by Janne Saarela (http:/ / baikalweb. jinr. ru/ doc/ cern_doc/ asdoc/ gks_html3/ node28. html)
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