MP1: Mesh Rendering

Assigned: Monday, February 2, 2009

Due: Monday, February 16, 11:59pm

• How to develop a simple window application for OpenGL using GLUT .
• How to use OpenGL commands to draw 3D objects with predefined colors.
• How to implement a mouse control (Arcball) interface to rotate a 3D object interactively.

All our example code will be written in C++. We assume that you already know C/C++. While we will not use any sophisticated C++ features, you should certainly understand the basics of control flow, method invocation, and class definition. Unfortunately, we simply do not have the time to provide any kind of substantial help in learning to program in C/C++, so it is your responsibility to learn (or refresh your knowledge of) the C++ skills necessary to complete this project.

Sample Models

To help you in preparing an interesting project, we are providing you with a selection of sample mesh models. You are free to use all, some, or none of them.

These mesh data files are stored as indexed face sets, meaning the vertices are stored as a list, followed by the faces which consist of ordered indeces of three of the vertices. This way each vertex need only be stored once, and referenced multiple times, once for each triangle that uses it. The format is simply a list of vertex coordinates, one per line, beginning with 'v' and followed by the xyz coordinates of the vertex, delimited by spaces. The vertex position list is followed by vertex color list, also one vertex color per line. It begins with "vc" and followed by the indices of RGB color. The color list is then followed by face list, one face per line, beginning with 'f' and followed by the indices of three (or more) vertices. The indices are base 1, so the first vertex is indexed by '1' and so on.

For example :

Here the three floating numbers "0.1 0.2 0.3" after the 1st "v" is the xyz position for the first vertex, and the numbers "0.8 0.8 0.8" after the 1st "vc" is its RGB color. The positions and colors for other vertices are determined accordingly. Similarly, three integers after the 1st "f" are vertex indices for the first face. Here it means the face is composed by vertex 1, 2, and 3.

   

Requirements

Grades will be assigned according to the following criteria :

• Object display (30%) : Read in 3D objects from the provided file and display them on the screen.
• Object coloring (10%) : Colored the 3D object using provided color values in the file or procedurally generating any interesting colors by yourself.
• Interactive viewing (40%) : Implement a mouse control mechanism such as Arcball to view the object interactive from different angle. The grading criteria depends on if the interface can rotate the object intuitively in any orientation.
• Efficiency (10%) : Your rendering should run in real-time and should be reasonably efficient. ( For example, don't read your object file in your display callback function. )
• Documentation (10%) : Your code should be commented or self-explanatory. A readme.txt should explain the features and special instructions ( if any ) to run your code.

Tips and hints

• Check back here often. Commonly asked questions on the newsgroup may be posted here in the future.
• Matrix/vector operataions such as dot product, cross product, and matrix-vector/matrix-matrix multiplications would be useful for this and following MPs. We recommend you to use some help functions for these operations and make the coding easier.
• We recommend avoiding quad/triangle strips and fans, unless you already feel comfortable with OpenGL drawing code. While your project will be marginally more efficient, it is slightly more difficult to implement correctly.

Handing in your Project

Important: Follow all handin instructions carefully. You may lose most or all points for failure to follow these instructions or if you do not hand in all required files.

You must turn in the following files:

• All source, header and Make/Project files (e.g., *.cxx, *.h)  necessary to compile your code.
• A README file named README.txt. It should contain the following information:
  • Your name and NetID
  • Whether you are an undergrad, 0.75 unit grad, or 1 unit grad student.
  • Clearly document how to use each feature you implemented, including inputting constants for equations if necessary.
• Any other files (e.g., libraries, data files) needed to compile and run your program.

To actually turn in your finished project, follow the hand-in instructions that we have provided.

Grading

Code-sharing, working together with peers, and copying code from other sources are only allowed under restricted conditions. Make sure you read the code-sharing policy for details.

Significant reductions will be imposed for projects that do not compile. If a project is handed in late, there will be a 20-point reduction (25 points for 1-unit grads) for every 24-hour period after the deadline.