CS5500 PC Representation.


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CS5500 PC Design April 19, 2007 Today's Theme Review of 3D pipelines. Extent of the following 2 or 3 assignments. Numerous Perspectives of Design Pipeline Straightforward "Front-End/Back-End" view. Course reading form in [Foley/van Dam].
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CS5500 Computer Graphics April 19, 2007 CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Today’s Topic Overview of 3D pipelines. Extent of the following 2 or 3 assignments. CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Many Views of Graphics Pipeline Simple “Front-End/Back-End” view. Course book variant in [Foley/van Dam]. David Kirk’s (nVidia CTO) adaptation displayed in EG Hardware Workshop 1998: (slide 05) http://www.merl.com/hwws98/presentations/kirk/index.htm CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Simplified View The Data Flow: 3D Polygons (+Colors, Lights, Normals, Texture Coordinates…etc.) 2D Polygons 2D Pixels (I.e., Output Images) Transform (& Lighting) Rasterization CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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A Quick Review By default, realistic pipeline will do the accompanying: Take as info different per-vertex amounts (shading, light source, eye point, composition facilitates, and so forth.) Calculate a last shading for every vertex utilizing a fundamental lighting model (OpenGL utilizes Phong lighting) For every pixel, straightly insert the three encompassing vertex hues to shade the pixel (OpenGL utilizes Gouraud shading) Write the pixel shading quality to the edge cradle CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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The View of DirectX 8 (Note: This figure is excessively swarmed so don’t stress over it in the event that you can’t comprehend it at the first look. The following slide may give you a superior thought of the pipeline.) CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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And a truly startling one… CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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The following 6 slides are acquired from UNC-CH COMP236 Course Slides (Spring 2003) http://www.unc.edu/courses/2003spring/comp/236/001/handouts.html CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Implementing a 3D Pipeline A contextual analysis - MESA. Plateau 3D Graphics Library A celebrated open source push to actualize OpenGL. Immaculate programming usage, importance all calculation is done on CPU, not on GPU. Used to call MesaGL, yet SGI grumbled about it because of client bolster issues. CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Two Different Approaches Consider how you anticipate that the clients will make the substance to your 3D pipeline. System 1: by giving 3D model records (e.g., in the OBJ or VRML group) Our methodology since it’s less demanding to execute. System 2: by composing an OpenGL program. MESA’s approach . CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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3D Models 3D Renderer MESA OpenGL summons OpenGLDrivers CPU & GPU CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Input File Format Very like an OpenGL “command stream,” for instance: Rotate point, x, y, z Translate x, y, z Color R, G, B, A Begin Triangle Vertex x, y, z ... End ... CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Major Components Data structures for: Points, vectors, lattices Lines and polygons (or just triangles) Frame support and compositions Transformation Lighting Clipping & Projection Rasterization & surface mapping CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Don’t Reinvent the Wheel A couple of helpful 3D vector and grid code: http://www.cs.nthu.edu.tw/~chunfa/code/algebra3.zip Or acquire one from your companions, or locate a decent one from the Internet. CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Graphics Hardware Why do we contemplate the illustrations pipeline in such profundity? Why not showing more Cg or shader programming? You’ve became acquainted with some equipment! They are all based upon the conventional 3D pipeline. CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Why Need Hardware All parts of design pipeline should be possible in programming. Yet, gradually. Illustration: mesaGL For a few applications, velocity is excellence Games Walkthrough Visualization CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Evolutions of Graphics Hardware Gouraud-shaded polygons. At that point came antialiasing. At that point came surface mapping. Presently comes programmable shading. CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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John Poulton’s Chart CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Fixed versus Programmable Starting in 1999 a few design cards utilized the standard lighting model and Gouraud shading to draw polygon parts totally in equipment Implementing the pipeline in equipment made preparing polygons much quicker, however the designer couldn\'t adjust the pipeline (subsequently “ settled capacity pipeline ” ) New programmable equipment permits software engineers to compose vertex and pixel projects to change the pipeline CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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OpenGL Fixed Function Vertex (object) Vertex (clasp) Transform [MVP],[MV],[MV] - T Normal Vertex (eye) Color SecondaryColor Front&Back Color [0,1] Lighting Front&Back SecondaryColor [0,1] Texgen Texture Matrix n TexCoord n TexCoord n EdgeFlag CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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GL2 Vertex Processor Vertex (object) Vertex (clasp) Uniform Normal Vertex (eye) Color SecondaryColor Vertex Shader Front&Back Color Front&Back SecondaryColor TexCoord n Temporaries TexCoord n EdgeFlag CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Programmable Shaders An idea made mainstream by Pixar’s RenderMan. Initially showed up in equipment: UNC PixelFlow See SIGGRAPH papers by Molnar 1995 and Olano 1997. Made reasonable by nVidia GeForce3 and XBox. CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Faked Global Illumination Shadow, Reflection, BRDF…etc. In principle, genuine worldwide brightening is unrealistic in current illustrations pipeline: Conceptually a circle of individual polygons. No connection between polygons. Can this be changed by multi-pass rendering? CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Future Trends Vertex/Pixel shaders will turn out to be more adaptable Less points of confinement on system size Able to execute branch directions Capable of moving entangled impacts (like those in Renderman) onto the GPU More and a bigger number of operations executed per-pixel as opposed to per-vertex As individuals get more imaginative with the equipment we will see more methods for non-photorealistic rendering CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Future Trends Real-time hide CS5500 Computer Graphics © Chun-Fa Chang, Spring 2007

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Future Trends More reasona

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