Task: Solved Exercise Of Graphics

1-List the operating characteristics for the following display technologies: Raster refresh systems, vector refresh systems, plasma panels and LCDs. Raster Refresh systems: Electron beam is swept across the screen, one row at time, from top to bottom. Each row is referred to as a scan line. As the electron beam moves across a scan line, the beam intensity turns on and off to create a pattern of illuminated spots. Vector Refresh Systems: The system cycles through the set of commands in the display file, drawing each component line in turn. After all line drawing commands have been processed, the system cycles back to the first command in the list. Plasma Panels: Constructed by filling the region between two glass panels with a mixture of gases that usually includes neon, a series of vertical conducting ribbons is placed on one gas panel and a set of horizontal conducting ribbons is built into the other glass panel. LCDs: Operating by producing a picture by passing polarized light from the surroundings or from an internal light source through a liquid-crystal material that can be aligned to either block or transmit the light. 3-Determine the resolution (pixels per centimeter) in the x and y directions for the video monitor in use on your system. Determine the aspect ratio, and explain how relative proportions of objects can be maintained on your system. Resolution is the number of points per centimeter that can be plotted horizontally and vertically although it is often simply stated as the total number of points in each direction. In my system the resolution is: 1280 by 1024 pixel The aspect ratio is an another property of video monitors which is now often defined as the number of pixels columns divided by the number of scan lines that can be displayed by the system (sometimes the term aspect ratio is used to refer to the number of scan lines divided by the number of pixel columns) aspect ratio can also be described as the number of horizontal points to vertical points (or vise versa) necessary to produce equal- length lines in both directions on the screen 14-Compare the advantages and disadvantages of three-dimensional monitor using a varifocal mirror to those of a stereoscopic system. The varifocal mirror vibrates, it changes focal length. These vibrations are synchronized with the display of an object on a CRT so that each point on the object is reflected from the mirror into a spatial position corresponding to the distance of that point from a specified viewing location. This allows us to walk around an object or scene and view it from different sides. Disadvantages: stereoscopic system does not produce true three-dimensional images. Advantages: it does provide a three-dimensional effect by presenting a different view to each eye of an observer so that scenes do appear to have depth. 15-List the different input and output components that are typically used with virtual-reality systems. Also, explain how users interact with a virtual scene displayed with different output devices, such as two-dimensional and stereoscopic monitors. Some of the input components that are typically used with the virtual-reality systems are: Data Gloves, Digitizers, Touch panels and Light pens Some of the output components that are typically used with the virtual-reality systems are: Stereoscopic monitors The user interact with a virtual scene displayed with different output devices by obtaining two views of the scene generated with viewing directions along the lines from the position of each eye (left and right) to the scene. We can construct the two views as computer-generated scenes with different viewing positions, or we can use a stereo camera pair to photograph an object or scene when we simultaneously look at the left view with the left eye and the right view with the right eye the two views merge into a single image and we perceive a scene with depth. 16-Explain how virtual-reality systems can be used in design applications. What are some other applications for virtual-reality systems? With virtual-reality systems, designers and others can move about and interact with objects in various ways. Stereoscopic viewing is a component in virtual-reality systems, where users can step into a scene and interact with the environment. 17-List some applications for large screen displays. Theses systems are designed for presenting graphics displays at meetings conferences, conventions, tradeshows, retail stories, museums and passenger terminals. 18-Explain the differences between a general graphics system designed for a programmer and one designed for a specific application, such as architectural design. General programming package provides a library of graphics functions that can be used in programming languages such as C, C++, Java, or Fortran. Basic functions in a typical graphics library include those for specifying picture components (straight lines, polygons, spheres, and other objects), setting color values, selecting views of a scene, and applying rotations or other transformations. Some examples of general graphics programming packages are GL (Graphics Library), OpenGL, VRML (Virtual-Reality Modeling Language), Java 2D, and Java 3D Special-Purpose packages are designed for nonprogrammers who want to generate pictures, graphs, or charts in some application area without worrying about the graphics procedures that might be needed to produce such displays. The interface to a special-purpose package is typically a set of menus that allows users to communicate with the programmers in their own terms. Examples of such applications include artist’s painting programs and various architectural, business, medical, and engineering CAD systems. 19-Explain the difference between the OpenGL core library, the OpenGL Utility, and the OpenGL Utility Toolkit. - In the OpenGL core library, function names are prefixed with gl, and each component word within a function name has its first letter capitalized. - The OpenGL Utility provides routines for setting up viewing and projection matrices, describing complex objects with line and polygon approximations, displaying quadrics and B-splines using linear approximations, processing the surface-rendering operations, and other complex tasks. Function names are prefixed with glu. - The OpenGL Utility Toolkit provides a library of functions for interesting with any screen-windowing system. Function names are prefixed with glut. 21-List the statement needed to set up an OpenGL display window whose lower-right corner is at pixel position (200,200), with a window width of 100 pixels and a height of 75 pixels. The glutInitWindowPosition function give an initial location for the top-left corner of the display window, so we calculate the top-left corner and it is (100,125). The statements are: glutInit (&argc, argv); // the GLUT initialization glutCreateWindow ("Window Title "); // for the title bar glutInitWindowPosition(100,125); //location from top-left corner glutInitWindowsize (100, 75); //size of display window 22-Explain what is meant by the term "OpenGL display callback function". The procedure that we set up to describe our picture is referred to as a display callback function. In general, OpenGL programs are organized as a set of callback functions that are to be invoked when certain actions occur.