PDA

View Full Version : Getting vertex data and compare to adjacent faces



rival
05-05-2011, 12:26 PM
Hello forum, first post here. I hate asking for so much help without being able to contribute anything, but I honestly I am willing to compensate for a considerable amount of help. Anyone willing to do the entire project I will pay for your time. I don't plan on taking my education in the field of graphics any further and I have enough work to do otherwise. Let's please not get into ethics of everything. Just ignore this request if you don't approve, I'm willing to take any help at all.

I have a graphics project due the Monday after next (5/16). What I have to do is take a previous student's work and emulate it. I chose Laplacian Lines. This takes a model and based on a light source will draw lines on the model dinamically. Here is a link to the paper: http://gmp.sce.ntu.edu.sg/papers/i3d09_ll.pdf and a link to the video: http://www.youtube.com/watch?v=1TPuOTiBXI4. (http://www.youtube.com/watch?v=1TPuOTiBXI4)

If I am properly understanding the paper, here are a list of steps I must do:

1- Precompile "Laplacian of surface normals" for each vertex. To do this I must first compute vertex normals using "weighted sum of the per-face normals". I can use a gaussian filter for smoothing, but this step isn't necessary. Then, using that data, I must compute the laplacian of surface normals by using formula (2) from the paper (it's fairly complicated so I won't post it just yet.)

2- The rest from here on is at run-time. Compute dot product of the view vector and laplacian normals from step one. Then locate the zero crossings (linearly interpolate the zero crossings) to find points on a laplacian lines.

3- Compute the "magnitude of gradient" using one of two options: a) "discrete differential geometry approach", or for a noisy mesh use b) formula (3) from the paper.

4- Trim the lines. Measure the strength of each line using the integral formula (4) from the paper. Remove lines less than the user input threashold.


If you want me to post one issue at a time and take this step by step let me know and I will follow up with a thread with my first question:
How do I get each vertex's data and compare it to the faces it is connected to?

rival
05-05-2011, 12:28 PM
I should also add that I am using OGRE to render.