CS 460: Interactive Graphics and Games
Project #2

Synopsis: Pick a component to add to your game engine from one of the categories below.

Due: This assignment is due April 4.  By Friday Mar 25 (sooner if possible) you should mail me a description of what project you plan to do and how it will fit into your game.  This is important!

Details: The rest of the assignments in the class will follow the same pattern.  Each student must pick one project from the following categories, with the constraint that no student can pick more than one project from any category (but note that some projects fit multiple categories), and with the additional constraints noted below.

1. Lighting effects: add some interesting lighting effects to your system:
   • Light maps: precomputed (or even hand painted) textures that capture low-frequency lighting information, combined with surface texture using multitexturing.
   • Shadows: shadow maps, shadow volumes, others.  Note: every group must implement a shadow algorithm at some point during the semester. 
   • Flare and glare effects: lens flare, optic glare, and chromatic aberration effects lend a sense of "photorealism" by simulating camera effects familiar from cinema.
   • Volumetric light effects: add "shafts of light" using techniques similar to shadow volumes.
2. Texture effects: add texture-related effects to your system:
   • Light maps: see above
   • Decals: these are things like bullet holes, char marks, and spattered blood (to pixk typical if violent examples) that get dynamically added to the scene by player actions.
   • Normal maps: write shaders to add visual detail to your polygons by perturbing the normal used in lighting according to a texture.
   • Imposters: add image-based imposters (dynamic or preprocessed)
   • Environment maps: use environment maps to get convincing glossy or reflective objects
   • Projective texturing: this technique projects a texture onto a surface like a slide projector.  Lots of special effects possible this way.
3. Shaders: use Cg or OpenGL Shader Language to implement interesting surface shaders in your engine
   • Normal maps: see above
   • NPR/toon shading:
     
   • Skinning: implement skinning on articulated characters.
   • Particle systems: write a vertex program to create time-varying particles: since vertex programs can calculate the vertex position as a function of time, they can be used to implement simple physical or non-physical particle systems.  For example, a vertex shader can compute the effects of gravity and wind on falling sparks.  Games use this technique frequently to implement explosions, fire, water, grass blowing in the wind, hair, "swarming points of light" magic effects, and yes, splashing blood.  You will probably want to combine such particle systems with the NV_POINT_SPRITE extension, which allows you to draw each vertex as a screen-aligned quadrilateral with a (possibly animated) texture applied. 
   • Deferred shading: if you want to use a VERY VERY complicated shader on lots of geometry in the model, it can be expensive to run that shader on pixels that eventually get depth-buffered away.  Deferred shading instead writes the shader parameters (e.g., normal, texture coordinates) to the framebuffer, then makes a pass over the entire screen (by drawing a screen-sized quad with the framebuffer applied as a texture, and running the very complicated shader on just those pixels that survived the depth test. 
4. Performance: Speed up your engine using acceleration techniques or just careful tuning.
   • Visibility: add portal culling, PVS managment, or some other form of occlusion culling.
   • LOD: add LOD preprocessing or run-time LOD management for objects, terrain, or shaders.
   • Imposters: add image-based imposters (dynamic or preprocessed).
   • Performance: profile, optimize, and tune your game engine to make it go as fast as possible.
5. Other stuff: a catch-all final assignment for some of the many other things that go into a good game.
   • Tools: build some tools for artists or level builders in 3DS Max or Maya
   • Physics: add some physical simulation to your game.
   • AI: add some AI to your game.
   • Special effects: fur, npr edge-based effects, water effects, clouds and fog, transparency, etc.
   • Camera control: intelligent "cinematic" camera control, instant replay, etc.

There are a few additional constraints.  Across the remaining four assignments:

1. Every group must implement a shadow algorithm
2. Every group must implement at least two acceleration or tuning projects from the "Performance" category.
3. Every group must employ multitexturing at some point
4. Two group members may not do the same project (though some projects allow for sufficient variation that they would not really be the same project. Just use common sense)

Furthermore, I explicitly do not want four individual assignments that don't work together.  Your project must be fully integrated with the group's game engine.  If your project doesn't work with the rest of the group's work, it will be considered late until it does. The group only turns in one codebase! 

Resources: Same resources as before. Here are a few new ones.  Feel free to amplify this list by sharing your own comments and pointers on the class forum.

• www.cgshaders.org: Plenty of sample shaders, some of them simply gorgeous, and forums where people will help you with dumb or not-so-dumb questions about Cg and programmable graphics.
• http://developer.nvidia.com: Tons of presentations, white papers, tools, and demos (with code!) explaining how to achieve various effects, or how to tie them together in a game engine.  Poorly organized but lots of great information.
• Papers!  Many algorithms are best described in the papers where they were first presented.  Browse the programs and proceedings of conferences like SIGGRAPH, the Symposium on Interactive 3D Graphics, Eurographics and it's subsidiary workshops/symposia, Graphics Interface, and Pacific Graphics.  Look on researcher's web pages for copies of the papers; sometimes you'll also find slides, movies, or even code demonstrating their techniques. We also have access to the ACM and IEEE digital libraries to get papers online (from inside JHU domain).
  

Also, don't forget about the optional texts for the course  -- they are all on reserve if you have not purchased them.

Policy on code reuse: Same policy: In general you are welcome to use code that you find elsewhere.  For example, you are welcome to use the lib3ds library mentioned above.  However, you will not get credit for what you didn't write.  Therefore, it is critically important that you describe in detail what code you wrote yourself and what code you imported or adapted from elsewhere.  Furthermore, if you find a particularly helpful library, tutorial, loader, etc., you should post it on the forum.  Obviously if you reuse a significant amount of code, that raises the bar for the assignment: you will be expected to do something beyond the basics mentioned above.  If you have any questions about code reuse or attribution, please ask me.

Turning in the assignment: Again, the group should turn in a single working program that demonstrates the various features added by individuals.  Put all your code and models in a folder, along with a detailed README.txt file that describes what your group did, who in the group did what, and any code or features added that aren't specifically part of an individual assignment (I expect that during every project, there will be some effort on the general game engine that is not reflected in an individual assignment.  You will get credit for these efforts as a group, and yes, general work on the game outside of the individual assignments will benefit the group's grade as a whole.  Each student in the group should include a separate document, e.g. README.cohen.txt, that describes in detail what you did, how you did it, what code you used from elsewhere, and how to demo your contribution in the game engine.  Zip up the folder and e-mail the .zip file (or a link) to me.  Be sure to include workspace and project files, along with any libraries/include files/etc, so that I can compile your code.  I will read (and grade you on) your source code, so follow good programming practices.

Grading: You will be graded on the difficulty as well as the success rate of your projects.  Not every project has to be a killer, but I expect every student to take on at least one substantially difficult project, and no more than one comparatively easy project.  Part of the reason you need to mail me a description of what you plan to do is to so that I can give feedback, if necessary, on how difficult I judge a project to be.