Volumetric Lighting and Shadowing NV30 shader

Version 1.1 (updated 06/11/2002)

and

• The scene was changed (the first is a debug scene that I wrongly selected when compiling the shader for the NV30 contest ! The interesting point is that there is a 2d quad (the one on the left) intersecting the 3d texture and showing a slice of the shadow volume).
  The original scene is:
  
  The new scene is:
  
  

This shader computes exact lighting and shadowing in volumetric data (ie. a 3d texture). The idea is to implement a ray marcher directly into the fragment program of the NV30. Each time a pixel textured by the volumetric data is rendered, a ray is cast towards the light. Densisty is integrated along the ray and then exact lightning is computed. This method allows to render colored shadows of semi-transparent objects. Thanks to CG and NV30 this can be entirely done in hardware. Moreover, if the 3d texture is applied to a geometric model the lightning computation is only done if the pixel is visible.

• Updated binary
• Updated source code

Here are some movies of the shader. All movies are encoded using DivX 5.0.2. Little movies are better with a 200% zoom factor.

• tree3f
• tree4f1
• tree4f0
• fish1
• fish2
• fish3
• mikado5
• mikado6
• mikado8
• mikado9

As this shader was done in a hurry for the contest, there is no user interface. So changing the scene should be done directly in the source code (it's ugly ... shame on me ;)

Simply choose one of the following lines (by commenting/uncommenting) in CVolumeObject.h:

 [CVolumeObject.h line 86]                  //m_uiDensTexId=buildCube();                 //m_uiDensTexId=buildNoise();                 //m_uiDensTexId=buildMikado();                 //m_uiDensTexId=buildFish();                 m_uiDensTexId=buildScene();