Re: [Flightgear-devel] Improved 3D Clouds patch

[Manuel M. <m.m...@wa...>]

Hi Stuart,

Attached is a small fix for the sorting in CloudShaderGeometry.cxx.
I think the sorting problem stems from the osg idiosyncracy
to store transposed matrices...so the intuitive

	osg::Vec4f p = vm * osg::Vec4f(_cloudsprites[i]->position.osg(), 1.0f);

needs to be replaced with...

	osg::Vec4f p = vm.preMult(osg::Vec4f(_cloudsprites[i]->position.osg(), 1.0f);

The patch also optimizes the distance calculation - it evaluates the distances 
in model space instead of eye space, which reduces computation to a dot-
product instead of a matrix multiplication.

bye, 

	Manuel