CS 445: Final Review, Fall 2012

The final will be Monday, Dec. 10, 2012, from 2-5 pm, and (for Ben) Tues Dec 11, 10am

Review class notes, online notes, labs, and relevant sections in textbook. The exam will be closed book, no calculators.

Topics

• Topics from first half of the semester. See midterm topics.

• Transformation Pipeline

  • Pipeline: Understand what the different stages of the pipeline do: geometry pipeline (also see pipeline).
  • Calculating u, v, n for the camera. Using these to create the viewRotation matrix.
  • View Matrix: Calculating the view matrix: V = viewRotation * Translate( -eye )
  • Modelview Matrix: Coordinate transformations of a point: Object Coordinates, World Coordinates, Camera Coordinates: see picture.
  • How do normals transform? If points transform as P' = M P, then the normals transform as N' = (M^-1)^T N. Why?
    For which transforms can one substitute M for (M^-1)^T?
  • What is the view volume or Frustum?
  • Projection Transformation: Orthographic and Perspective. See the methods in mat.h: Ortho(), Frustum(), Perspective(). What is the purpose of the projection transformation? How does it change the frustum?
  • What is the Perspective Division? Why is it separated out from the projection transformation?
  • What is rasterization?

• Controls for Navigation through a scene - See code from lab.

  • Fly through transformations.
  • Tumble, track, dolly

• Shading in OpenGL

  • Shaders and the openGL pipeline: Where do vertex and fragment shaders fit in the OpenGL graphics pipeline. What do the shaders do and what does openGL do.
  • What is a vertex shader vs what is a fragment shader.
  • Communication between openGL and GLSL - uniform and attribute variables. What is the difference?
  • Implementing the Phong Lighting Model in the vertex shader vs the fragment shader.
  • Shading Models: Flat Shading, Gouraud Shading, vs Phong Shading
  • Implementing a color map in the shader.
  • Advanges of using shaders over the fixed pipeline. E.g. why can't the OpenGL fixed pipeline implement bump mapping or the Phong Lighting Model?

• Blending and transparency with the alpha component.

  • How does a z-buffer work?
  • Why is it difficult to do transparency correctly? See blending.
  • How does the "discard()" function work in a programmable shader and why is it not possible to get the same effect in fixed pipeline.
  • Implementing shadows

• Textures

  • Texels
  • Coordinate systems: texture (s,t), parameterized (u,v), world (x,y,z), screen (x_s, y_s).
  • Texture coordinates in OpenGL. How does the choice of texture coordinates determine how the texture is applied to geometry, e.g. a quad. (see Nate Robins tutorials)
  • Texture parameters: wrap type - repeat vs clamp
  • Combining lighting and texture in shader.
  • Generating textures: procedural vs image
  • What is bump mapping?
  • What is Mipmapping - multum in parvo (many things in a small place)

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