PARALLAX OCCLUSION MAPPING WITH SOFT SHADOWSCSCI580: 3-D Graphics and Rendering

Bump Mapping A Perturbation to the

surface normal is looked up in a texture map.

The change is then applied before the illumination calculation is done.

Pros : Richer, more realistic and detailed surface

Cons : Does not exhibit parallax and self shadowing.

Normal Mapping

Illusion of bumps and dents without using a high number of polygons.

A 3 channel bitmap containing surface normal data is called a normal map.

The RGB channels of the map represent the X,Y,Z values of the normal vector.

These values are used as normals for a given pixel.

Parallax Mapping – An Introduction Also known as offset

mapping An enhancement of the

bump mapping or normal mapping techniques

Textures appear to have more depth and realism with less impact on performance.

Displays motion parallax.

Parallax DisplacementView Ray

Displaced point on surfaceExtruded Surface

Polygonal Surface0.0

1.0

Result of Normal Mapping

Input Texture coordinate Texture coordinate offset(u, v)(u’, v’)

δ

Parallax Occlusion Mapping

Soft Shadows In the algorithm, we

continue sampling the height field along the light ray past the first shadowing horizon until we reach the

next fully visible point on the surface.

Then we filter the resulting visibility samples to compute soft shadows with smooth edges.

Parallax Occlusion Mapping with Soft Shadows

References

Wikipedia - http://en.wikipedia.org/wiki/Parallax_mapping

GameDev.net - http://www.gamedev.net/columns/hardcore/pom/

Practical Dynamic Parallax Occlusion Mapping by Natalya Tatarchuk  -

http://ati.amd.com/developer/techreports/2005/SIGGRAPH2005/Tatarchuk-ParallaxOcclusionMapping-Sketch-SIG05-Slides.pdf fxComposer by Nvidia GamePipe Game Engine by GamePipe Labs, USC http://www.bencloward.com/tutorials_normal_map

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