Hi,
As a propnent of IMPROVE_TEXGEN_PRECISION fix I feel I should make a
response but I am not sure what your problems really are. Tweak in
ShadowMap was related to the way OSG & OpenGL computes final texture
coordination matrix. I assume you have read OpenGL documentation and you
know how Texgen with eye space works. Texture coord matrix is computed as
multiplication of current inverted view matrix and texgen planes. Problem is
that OpenGL internally uses float matrices. So if our View and TexGen
matrices use large coordinates (for example large translations when objects
are located on earth surface in WGS84 cartesian representation) and are cast
to float matrices we loose lots of math precision. Their multiplication
sucks even more. Solution to this was to make sure that large coords are
multiplied in OSG using double matrices.
When you use shaders you are not limited by this functionality and you mays
skip using fixed pipeline gl_EyePlane uniformsl. You may simply compute your
own tex coord matrix by multiplying inverted view and tex gen using OSG
double matrices. Then pass this result as an uniform to your shaders and
compute tex cooords by multiplying view coords by your matrix.
Cheers,
Wojtek
Hi guys, I followed this excellent thread
http://thread.gmane.org/gmane.comp.graphics.openscenegraph.user/31360 with
much
success. I was able to mimic texgen in the vertex shader and get shadows
applied in the frag shader. However, the quality doesn't match what you
get
with ShadowMap using fixed function vertex processing and I believe I can
see
where it's coming from. In ShadowMap.cpp there exists the macro constant
"IMPROVE_TEXGEN_PRECISION". What I have in the shader doesn't take this
enhancement into account. Anyone know how this can be done?
Thanks,
Michael Guerrero
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