CSE 494/598 Intro to Applied Computer Graphics Anshuman Razdan DCST AR's Web Page AR's Web Page

Anshuman Razdan and Peter Wonka 1 Disclaimer These slides can only be used as study material for the class 494 at ASU The slides cannot be distributed or used for another purpose The slides may contain errors The slides do not contain all the information necessary to succeed in class; additional material from the book must to be studied The slides are based on a lecture from Prof. Purgathofer from the Vienna University of Technology

Chapter 2 Overview of Graphics Systems

Anshuman Razdan and Peter Wonka 3 Objectives Understand the basics of commonly used input and output devices Get started with OpenGL

Anshuman Razdan and Peter Wonka 4 Cathode-Ray Tubes: Overview Cathode-Ray Tubes = CRT

Anshuman Razdan and Peter Wonka 5 CRT: Terms Refresh Rate = frequency at which an image is redrawn 60 Hz (gives me headache) / better 75 – 120 Hz Resolution = number of points that can be displayed without overlap, e.g x 1200 Phosphor color persistence = how long does the phosphor emit light (10% threshold) Raster scan

Anshuman Razdan and Peter Wonka 6 CRT: Raster Scan

Anshuman Razdan and Peter Wonka 7 CRT: Terms Scan Line Frame Buffer color values + other values (stencil, depth, alpha, …) Pixel = picture element Aspect Ration 4:3 most monitors 16:9 HDTV 16:10 some monitors (show 2 pages of text side by side) beware: alternate definitions exist

Anshuman Razdan and Peter Wonka 8 CRT: Terms Depth number of bits per pixel in the (frame) buffer typical: 3 * 8 = 24 bits for the color = true-color system more bits are coming for High Dynamic Range Displays general purpose calculations Horizontal Retrace before new scan line Vertical Retrace before new frame Random-Scan Displays (old technology)

Anshuman Razdan and Peter Wonka 9 CRT: Color Monitors

Anshuman Razdan and Peter Wonka 10 Flat-Panel Displays Flat-Panel: less volume, weight, power requirements compared to CRT Emissive Displays convert electrical energy into light Plasma Panels = gas-discharge displays light emitting diodes Thin-film electroluminescent displays Nonemissive Displays optical effects to convert light into graphics patterns LCD passive matrix active matrix (transistors) more details:

Anshuman Razdan and Peter Wonka 11 Plasma Panel / Thin-film electroluminescent display

Anshuman Razdan and Peter Wonka 12 LCD light can be polarized e.g. vertical, horizontal

Anshuman Razdan and Peter Wonka 13 LCD States of Matter: Solids: molecules maintain their orientation + molecules keep same position with respect to one another Liquids: molecules change orientation and can go anywhere Liquid Crystals: maintain orientation + can go anywhere Nematic Liquid Crystals

Anshuman Razdan and Peter Wonka 14 LCD

Anshuman Razdan and Peter Wonka 15 Stereoscopic and virtual reality systems Idea: Show different image to right eye and left eye Head mounted displays head tracking Active Stereo Glasses + infrared emitter use shutter to switch between left and right eye Passive Stereo different polarization filter for left and right eye

Anshuman Razdan and Peter Wonka 16 Raster-Scan Display Processor Graphics Card / Display Processor / Graphics Controller Digitizing geometric objects into pixels scan conversion: e.g. input: triangle (three vertices) output: colored pixels in the frame buffer now: your graphics card is much more powerful than the CPU!!!

Anshuman Razdan and Peter Wonka 17 NV40 – Nvidia Graphics Card Monitor Video Controller

Anshuman Razdan and Peter Wonka 18 Decision Theater at Arizona State University Large Viewing System

Anshuman Razdan and Peter Wonka 19 Input Devices Keyboard Mouse Trackball Joystick Data Gloves Digitizers Scanner Touch Panels Light Pens

Anshuman Razdan and Peter Wonka 20 Graphics Software VRML OpenGL (used in this course) Java 2D Java 3D Direct 3D

Anshuman Razdan and Peter Wonka 21 Transformations: a first look

Anshuman Razdan and Peter Wonka 22 OpenGL OpenGL basic library – most commands OpenGL Utility (GLU) – some high level commands e.g. generating complex objects, cylinder, sphere OpenGL Utility Toolkit (GLUT) windowing commands

Anshuman Razdan and Peter Wonka 23 Commands Commands are prefixed by gl glBegin, glClear, glCopyPixels Constants are Uppercase seperated by “_” GL_POLYGON Datatypes GLbyte, GLshort, GLint, …

Anshuman Razdan and Peter Wonka 24

Anshuman Razdan and Peter Wonka 25 Example Program First Example (Basics.zip)