SSAO

by Jiaxi Ye

CS291A Project 4

Usage

In the project root directory,

$ mkdir build

$ cd build

$ cmake ..

$ make main

In the project /build directory,

$ ./main [path_to_obj_file(optional)]

e.g.

$ ./main ../model/Guitar.obj

This program performs Screen Space Ambient Occlusion, with kernel rotation and filtering.

Geometric Shader:

Transform objects. Rasterize the scene.
Generate positions (depths) and normals.
Screen Shader:

Perform SSAO to compute the occlusion factors of each pixel. The kernel has 64 sampling points, randomly distributed within a hemisphere of radius 0.02 (in screen space). It is randomly rotated at each pixel.
Filter Shader:

Apply bilateral filter to occlusion factors.
Do the shading of diffuse and ambient light, and then blend with the occlusion factor.

Halo.

Slight halo is observed along object edges of two areas with highly different depth value.
Also, it's observed that the halo becomes less obvious when the size of SSAO sample kernel gets smaller.
Dark stripes (fixed).

Dark stripes problem has been fixed by offsetting the sample kernel by a tiny constant distance (0.01) along the normal direction.
Thank you, Pf. Yan!

SSAO off

SSAO with filter

SSAO without filter