These are four screenshots of my Drops of Water shader. It is an animated
showing drops falling allong a surface. The shader relies on a
fragment program and therefore no geometry is required for the rendering of
drops: all is done in texture space. The two pictures on the left are only
geometric quad textured with the shader. The drop shape is encoded in a
texture. The shader instanciates the drops in texture space where asked by
application. A transformation (scaling and rotation) can be applied on each
drop. All happen like if drops were sprites drawn in the texture.
The rendering of drops is done using a faked refraction effect. The
of the underlying surface is done with the Phong model. The specular and
coefficient are modulated by a texture to achieve a wet effect. This texture
represents the wet areas. It is obtained by rendering the drops as white
at each time step. The new state is blended with the old texture to
accumulate wet areas.
The Drops of Water shader will be explained in detail in the upcoming
Videos are available at http://www.aracknea.net/shaderx2/