Projective texture mapping: Difference between revisions

Revision as of 09:25, 24 February 2007

Revision as of 15:25, 18 October 2007

Line 26:

According to the used texture wrap mode various artifacts may occur but it's obvious a shift and scale operation is definitely necessary to get the expected result.

The other problem is actually a mathematical issue. It is well known the matrix math used produces a back projection. This artifact has historically been avoided by using a special black and white texture to cut away unnecessary projecting contributions. Using pixel shaders a different approach can be used: a coordinate check is sufficient to discriminate between fowardforward (correct) contributions and backward (wrong, to be avoided) ones.

== References ==

#{{note|nvsdk_ptm}} The [http://developer.nvidia.com/object/Projective_Texture_Mapping.html original paper] from the [http://developer.nvidia.com nVIDIA developer web site] includes all the needed docuentationdocumentation on this issue. The same site also contains [http://developer.nvidia.com/object/projective_textures.html additional hints].

#{{note|glEyeLinear}} Texture coordinate generation is covered in section 2.11.4 "Generating Texture Coordinates" from the [http://www.opengl.org/documentation/specs/ OpenGL 2.0 specification]. Eye linear texture coordinate generation is a special case.

#{{note|glTCXFform}} Texture matrix is introduced in section 2.11.2 "Matrices" of the [http://www.opengl.org/documentation/specs/ OpenGL 2.0 specification].