Midterm Study Guide

Questions on the midterm exam will be taken primarily from among these topics:

• Frame buffers
• Know the relationships between the number of bits per pixel and the number of colors that can be produced
• Graphics API design considerations
• Understand the tradeoffs between simple and complex primitives, and the reasoning behind the use of state in APIs such as OpenGL
• Simple OpenGL primitives
• Know the difference between points, lines, line strips, line loops, and polygons
• Viewport transformation
  • Know how the viewport transform maps the canonical projection plane to the display window. 
  • Understand the default viewport transformation in OpenGL, and how it works when windows are reshaped.
• Logical input devices
• Understand the concept of logical input devices, especially position, string, select, valuator
• Input modes
• Understand the three input modes, and the primary advantages of event-mode input
• GLUT input processing
• Understand how GLUT uses event mode input with callback functions
• Homogeneous coordinates
  • Understand the motivation for expressing points and vectors in homogeneous coordinates. 
  • Be able to give the homogeneous coordinates for an (x,y,z) point.
• Affine transformations
  • Understand how affine transformations work and their representation as 4x4 matrices. 
  • Be able to transform the homogeneous coordinate representation for a point, given the representation of a transform.
• Camera positioning
  • Understand how OpenGL positions the camera at the origin in "eye coordinates."
  • Understand how to use translation and/or rotation to produce the effect of moving the camera.
  • Understand the function gluLookAt().
• Using transformations in OpenGL
  • Be familiar with the API function calls in OpenGL to do rotation, scaling, and translation
• Parallel and perspective projections and associated transformations
  • Understand the difference between parallel (=orthographic)  and perspective projection transformations. 
  • Be able to identify the transformations given their representation as 4x4 matrices (look at the bottom row)
• Z-Buffering
  • Understand how z-buffering works and be able to describe the effects of turning z-buffering on and off given a particular drawing scenario
• Double Buffering
  • Understand what double buffering is.
  • Understand when you would want to implement double buffering and how it is done using glut.
• Lighting and materials in OpenGL
  • Understand the simplifying assumptions used in OpenGL for lighting. 
  • Understand the difference between directional lights, point sources, and spotlights. 
  • Understand the three types of material interaction, and be able to identify the best representation for a given type of object properties from given choices.