Computer Graphics		CMSC 212
Haverford College		Fall 2003
Lab 4		Wednesday, November 5

Rendering of Polygon Meshes with Shading

This project generalizes work from the previous lab assignment, and should not be started until the previous one is completed successfully (see instructor a more precise definition of "successfully"). In fact, many of the labs build on each other, so proper programming organization and documentation are essential throughout the course. You may want to return to the previous lab and reorganize it so it is simpler to extend.

Design and implement a program to accept text input for a local file named "universe.ent" that dictates the camera and a world consisting of a set of "entities", where each entity is either a polygon-mesh or a light source. Each entity is also defined is in a separate file (also with the ".ent" suffix). The general format of the universe.ent file is given here:

camera                  //string
e.x e.y e.z
l.x l.y l.z             //9 doubles
up.x up.y up.z
projection type         //string(parallel || perspective || frustum)
//if parallel:
xmin xmax
ymin ymax               //6 doubles
zmin zmax
//if projection:
width
height                  //3 doubles
distance from camera
//if frustum
xmin xmax
ymin ymax               //3 doubles
zmin zmax
num of objects          //int
for each object, a filename (.ent)

The format of a polygon-mesh text file has been extended to hold materials properties for each face, and is given here (.ent) is given here:

polygon-mesh            //string
number of faces         //int
//for each face:
ambient  a.r a.g a.b a.alpha	// string, then 4 doubles, each 0 <= x <= 1
diffuse  d.r d.g d.b d.aplha	// string, then 4 doubles, each 0 <= x <= 1
specular s.r s.g s.b s.alpha	// string, then 4 doubles, each 0 <= x <= 1
emissive e.r e.g e.b e.alpha	// string, then 4 doubles, each 0 <= x <= 1
number of vertices      //int
//for each vertex:
x y z                   //3 doubles

The format of a point-light-source (.ent) is given here:

point-light-source		// string
l.x l.y l.z			// location
ambient  a.r a.g a.b a.alpha	// string, then 4 doubles, each 0 <= x <= 1
diffuse  d.r d.g d.b d.aplha	// string, then 4 doubles, each 0 <= x <= 1
specular s.r s.g s.b s.alpha	// string, then 4 doubles, each 0 <= x <= 1

Extra and optional: The format of a spotlight (.ent) is given here:

spotlight			// string
l.x l.y l.z			// position of spotlight (3 doubles)
d.x d.y d.z			// direction of spotlight (3 doubles)
cutoff ang			// string, then double for angle
exponent exp			// string, then double
ambient  a.r a.g a.b a.alpha	// string, then 4 doubles, each 0 <= x <= 1
diffuse  d.r d.g d.b d.aplha	// string, then 4 doubles, each 0 <= x <= 1
specular s.r s.g s.b s.alpha	// string, then 4 doubles, each 0 <= x <= 1

Sample scene files are available at the path /Network/Servers/moe.cs.haverford.edu/Users/jd/courses/212/examples:

• par.universe.ent: parallel projection
• per.universe.ent: perspective projection
• pyramid-shade.ent: pyramid with illumination information
• light1.ent: point light source

Some things to consider before final submission of the lab:

• Your program should support parallel and either frustum or perspective projections (please tell me explicitly in a comment which mode your program supports).
• Sample universe files will be made available.
• You are welcome to use OpenGL/GLUT calls, or build your own functions.
• You should assume that the set of meshes can be of size >= 0, so some list of objects is advisable.
• Finally, you do not need to fly the camera as in the initial sequence of labs, but you are welcome to include code for that for extra credit.
• Again, please submit either a file or a folder into the cs212 dropbox using the name convention login.4 (e.g., jdougher.4.cc).

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