GPU Final Project Summary

Paper:
https://docs.google.com/open?id=0B21htwSnbMf0VDhsNmJMa1hMUGc

Videos:
Multiple Lights:
http://youtu.be/IXdIWSlp_Ys

Explosion:
http://youtu.be/WBxcCZdamR8

Novel Interface for Seeing planes of grid data one after another:
http://youtu.be/Zb-qwwt50-U

Slices of a Cloud:
http://youtu.be/PrJ_jHe3JPc


Presentation Slides:
https://docs.google.com/open?id=0B21htwSnbMf0M0hvb2RBMUdPaUk

Midpoint - Final Project

Here's a link to my midpoint presentation:

https://docs.google.com/open?id=0B21htwSnbMf0M0hvb2RBMUdPaUk

Final Project Pitch

Project Pitch

I propose to develop a WebGL based real time volumetric renderer and (if time permits) use it to render physically based smoke simulation. Volume rendering is a well-known technique used for rendering data that is typically stored in the form of a grid. Some problems can be solved very efficiently and are naturally suited to be solved when space is portioned into an imaginary uniform grid structure. Some common examples are rendering clouds, smoke, fire, etc.

Generating images based on this method has been traditionally done in an offline manner, i.e. images are not generated as soon as data is available; putting it more precisely, images cannot be generated at 30 fps or greater. However, volumetric rendering technique is “embarrassingly parallel”, which means that the technique can be parallelized with little effort. The first step in the process is to generate a ray for each pixel of the image that we want to generate. Then we can gather densities along each ray independently on separate fragment shaders. The process can be further optimized if we only ray march within the region containing voxels.

I would be using 3D textures for storing the voxel data if it is supported in the latest WebGL specification. If it is not, then I would have to use 2D textures and simulate 3D textures.

The main challenge in the project is using WebGL for doing all of the above. Being a graphics guy, my work has mainly been in C++ and C++ like languages. It’s going to be a steep learning curve for me to use JavaScript for doing graphics. 

Once I am done with the rendering, I would start working on creating physically based smoke simulation. I propose to use the Semi-Lagrangian method for smoke simulation, meaning I would be using parts of both a particle based (Lagrangian) approach and grid based (Eulerian) approach. The Eulerian approach enables us to parallelize smoke simulation conveniently on the GPU. Every grid element stores both scalars (like density, pressure, temperature) and vectors (like velocity) which get modified during the simulation. The densities computed in each step of the simulation would then be transferred to the volumetric renderer for visualization.

I would be referring to Chapter 30 of the book GPU Gems 3 for my implementation:

http://http.developer.nvidia.com/GPUGems3/gpugems3_ch30.html

Starting WebGL

Wave simulation in WebGL using Sin and Cos functions

Simplex Wave

Rotating Ellipsoid

With these mini projects, I start WebGL projects.

Image Processing

Video of all the different image processing done using GLSL

Implemented the following (in same order as shown in video):

• Box Blur
• Image Negative
• Gaussian Blur
• Color to Grayscale
• Edge Detection
• Toon Shading
• Brightness Enhancement
• Old TV look
• Pixelated look
• Image Rotation

Image Swirling

I also added this feature which I like much.

CUDA Rasterizer

CUDA Rasterizer - featuring Bovine

Implemented some core parts of the raster pipeline:

• Vertex Shader
• Primitive Assembly
• Geometry Shader
• Rasterization stage
• Fragment Shader

Other features:

• Mouse interaction
• Back Face Culling
• Multiple Lights

During  the initial phases of the project, I used a nifty trick shown to me by Shehzan, which involved using Maya for getting an approximate view of the output from the rasterizer (this was useful for testing):

 

GPU Path Tracer