CMPS 160 -- Prog 2

Early if time stamp is before midnight Oct 28, 2017.
On time if time stamp is before midnight Oct 29, 2017.
Late submissions will not be accepted/graded.

Objectives:

Description:

Details:

• Light source. Use the same light source and viewer setup as in previous program. That is, the light source is pure white (1, 1, 1) and is coming from the direction [1, 1, 1]. The viewer is at (0,0,∞).
• Specular lighting. Specular lighting produces specular highlights. This lighting component combines the geometry information (surface normal), the lighting direction, and the viewer direction. The material specification for the GC is modified to:
  Ka 0 0 0.2
  Kd 1 0 0
  Ks 0 1 0
  Ns 1
  Note that Ns is the glossiness factor. Its initial value is 1, but can be scaled up to 20 via a slider that you need to provide to the user.
• Toggle specular lighting. Provide a toggle button to turn specular lighting on or off. By default, it is off. If it is on, the observed color is the sum of both diffuse and specular lighting. Otherwise, it is just the diffuse lighting. Make sure that individual rgb values are capped at 1.
• Gouraud (smooth) shading. This is achieved by calculating a color per vertex (instead of a color per polygon) and then passing the vertex color to the fragment shader to interpolate across the polygon. Calculating the vertex color requires a vertex normal. The vertex normal is simply the average of the polygon normals that share the same vertex.
  • The vertex color can be calculated in the CPU and passed to the fragment shader, or it can be calculated in the vertex shader which then passes the vertex color to the fragment shader.
  • You also have the option of implementing flat and smooth shading in their own shader programs or in a single shader program.
• Toggle smooth shading. By default, surface rendering will use flat shading. Provide a toggle button to switch the rendering to smooth, or back to flat, as the button is repeatedly clicked. Note that this is an independent toggle than the one used for lighting. That is, one can have 4 combinations:
  • flat shading and diffuse lighting only,
  • flat shading with both diffuse and specular lighting,
  • smooth shading and diffuse lighting only, or
  • smooth shading with both diffuse and specular lighting.

  Resource:

  Directional lighting.

  Diffuse reflection with directional light source LightedCube code from the Matsuda-Lea book.

  Specular lighting example. Note that we use the same weights for diffuse and specular lighting. Also this example uses a point light source while we use a directional light source. Look at this example again for Lab3 to see how to handle point light sources. Don't get hooked up on the details -- understand concepts and translate to Matsuda-Lea convention.

  Phong smooth shading. Note that they refer to this as per-fragment lighting where the lighting calculation is carried out for each pixel. In this assignment, we want per-vertex lighting or Gouraud shading where the lighting calculation is carried out for each vertex. The following link shows the difference between the two. Don't get hooked up on the details -- understand concepts and translate to Matsuda-Lea convention.

  Input types handled by HTML5. Try out the button and range input types for use with your toggles and sliders.

  Grading:

  • Rubric:

    You start off with 100 points.  You earn additional credit by turning in your assignment
    early and/or implementing additional features.  You lose credit for missing functionality,
    incorrect results, poorly documented or formatted code, or not following instructions.
    
    Below is a partial list:
    
    - up to 10 points off for poor features.html file
    - up to 10 points off for inadequate comments or hard-to-read code
    - up to 10 points off for not following instructions
    - up to 10 points off for special handling to grade your homework (usually
      because you did not check that it runs on the computers in the lab first).
    - functionality points depending on importance
    
    Make sure you:
    a.  submit the right files you want us to grade,
    b.  have tested your code on the browsers in the lab.
    c.  follow the general instructions described in overview.html
    
    

  • Who graded your assignment based on your login name:

    hugh:	a - k
    cole:	l - z
    

  Submission:

  See course overview for instructions on what to submit and what not to submit.

  Put materials in a folder named prog2 and zip it up. Submission must be done using the "submit" command from unix.ucsc.edu

  • submit cmps160-ap.f17 prog2 prog2.zip

  ---

  Last modified Tuesday, 22-Jan-2019 09:42:16 PST.