Tuesday, November 6, 2012


Vertex Shader & Primitive Assembly
I started coding for CUDA rasterizer on Monday this week. But all  thanks to Sandy, I lost my power by midnight. BY that time I finished my vertex shader and primitive assembly. They were straight forward.

I used following blogs for the implementation: http://www.opengl-tutorial.org/beginners-tutorials/tutorial-3-matrices/

 On thursday morning, yes thats when my light came back, I started working on rasterization step. It took me 2 days to complete it.

 The major difficulty I was facing was that my code kept crashing for resolution greater than 200 by 200. Its still not working for more than 400 by 400. Also, when I implemented atomics in the code, Visual studio was not able to recognize any of the atomic functions. The reason was that I was using CUDA 4.2 instead of CUDA 4.0. Hence , I change the setting in projectProperties->CUDA->Device-> code generation to sm_20 instead of sm_10.

Fragment Shader
Now, I have implemented fragment shader as well.

But the phong highlight is not very apparent from the image. May be due to the resolution. But, I would not worry about the resolution for now. First I will complete the other functionality.
I can set the resolution of 800 by 800 for the cow but not for the cube.

Back Face Culling
Just Implemented Back Face culling.

However, sometimes there is a lag in generating a face while the model is continuously rotating.
I resolved it by increasing the threshold for the dot product comparison.
There is one more issue that it is slow after implementing back face culling. Gives 9 FPS otherwise it is 12 or 13FPS.

Scissor Test
The most easiest part of the assignment. Increases the render rate to 15-16FPS.

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