Graphics Programming
Simulating Rigid Body Dynamics Using Mass-Spring Systems.

Simulating rigid body dynamics traditionally requires knowledge of many different facets of physics and mathematics. In such a simulation we must define the state of the body at any given instance of the simulation. In order to accomplish this we must calculate the following data:

- mass and moments of inertia
- position and velocity of every object
- rotational and angular force/momentum
- torque
- velocity and acceleration, linear and rotational
- numerical integrator

Flexible body dynamics calculate position, velocity, acceleration, and force using particles, mass-springs, and a numerical integrator (this project uses 4th order Runge-Kutta), to run the simulation. This requires much less background of physics and mathematics. This is the idea of Dr. John McDonald's paper "On Flexible Body Approximations of Rigid Body Dynamics." This project attempts to construct the ideas proposed in this paper. Specifically, this project simulates the dynamics of a toy top rotating, slowly loosing momentum, interacting with boundaries in space, and eventually toppling over on its side.
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Efficient Soft-Edged Shadows Using Percentage Closer Filtering and Pixel Shader Branching.

Shadow map techniques are employed in computer graphics to improve visual realism. The shadow map algorithm requires a two pass render of a scene. Once from the light's perspective and a second from the camera's perspective. The render from the light's perspective records the depth values from the light source to each object in the scene. The depth values are written to a pbuffer, then stored in a texture where it can later be sent to the fragment shader as a uniform sampler. When rendering the scene from the camara's view, each screen pixel is transformed to light coordinates where its z-value is compared to the value stored in the shadow map. This compare operation is performed in the fragment shader using the shadow2DProj function. If the pixel's z-value is higher than the depth value of the shadow map then that pixel is in shadow. If the pixel's z-value is lower than the depth value stored in the shadow map then the pixel is not in shadow.

One inherent side effect of shadow maps is a hard, aliased edge around the shadow. Building soft edged shadows using percentage closer filtering and pixel shader branching is a visual enhancement to the shadow map that employs optimization mechanisms for calculating a soft penumbra region around a shadow where we previously had a hard, aliased edge.
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OORenderGL Software Rendering System.

OORenderGL is a software rendering system. A skeleton framework was provided and I implemented, using C++ and OpenGL, a rendering systems that encapsulates the following fundamentals of graphics development:

- Faceted, Gouraud, and Phong shading
- Texture mapping, uv coordinates, mesh data structures
- Applying textures to a mesh using shape, entity, and mapaxis
- OpenGL texture mapping and filtering functions
- Box mapping, reflection mapping, light mapping, and environment maps
- OpenGL transformation pipeline
- Matrix operations for interactive display such as rotating, translating, and zoom
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Network Programming
Distributed Shared Memory.

The Distributed Shared Memory client and server are fully implemented with multicasting, multithreaded over UDP protocol. Multicasting realiability is built into mdsmc using select with a timeout value. If timeout occurs mdsmc resends reqeust to multicast groups until all servers reply. mdsmd is multithreaded, each request occurs in its own thread. Race conditions are prevented by using mutex. Mutex locks the entire table DSM table for new and delete requests, and locks the respective table entry for read and write reqeusts. mdsmc sends all requests to mcast group through the mcast socket specified by command line arguments. All replies are received on a separate receive socket. mdsmd receives all requests through mcast sockets specified by command line arguments. All replies are sent on a separate unicast socket.
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Web Development
Flash Media Design Portfolio.

The Flash Media Design Portfolio is exactly that - nothing more to say.
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Alien Invaders Flash Game.

Alien Invaders is a space invaders / classic arcade style game composed in flash.
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