This set of scenes each use a shader downloaded from GlslSandbox.com
as a background to a single performer.  Because  the  VGHD  software
uses non-standard names for some of the shader inputs, and others do
not seem to be supported at all, it has been necessary to make a few
modifications to the downloaded sources.  However,  these  have been
kept to a minimum and generaly comprise

   Using #define to equivalence the VGHD and standard names

   Faking out Mouse references.

This was done by adding the following code to each shader

   uniform float u_Elapsed;    // The elapsed time in seconds
   uniform vec2  u_WindowSize; // Window dimensions in pixels
   
   // Use defines here rather than edit the body of the code.
   
   #define time u_Elapsed
   #define resolution u_WindowSize
   #define mouse vec2(0.0,0.0)
   #define surfacePosition vec2(gl_FragCoord.xy/resolution)

and commenting out the originals' definitions of  time,  resolution,
mouse and surface position. This automatically replaces the shader's
inputs with those provided by VGHD with the mouse being "stuck" in a
corner of the screen. In a few cases a different definition has been
used for mouse, one that simulates mouse movement, e.g.

   #define mouse AUTO_MOUSE

   #define MOUSE_SPEED vec2(0.1,0.177777)*0.1
   #define AUTO_MOUSE  vec2((1.0+cos(time*MOUSE_SPEED))/2.0)

where both the MOUSE_SPEED and the form of the AUTO_MOUSE expression
can be changed to suit the particular needs of the shader.

Occasionaly #defines have been used to allow shader parameters, such
as maximum iteration counts,  to be easily changed in order to lower
the resources used by a shader.  This is useful for scenes which use
a lot of resources and stress the host system leading to judder when
a scene is played.

TheEmu can take no credit for any of these shaders,  that belongs to
there original creators and the names used for the scenes do reflect
this. However, unlike at ShaderToy, the scenes at GlslSandbox are not
titled and the creators or uploaders are not identified, unless this
information is to be found in the shader source itself.  Therefore I
have only been able to identify creators for a few of these  shaders
and have also had to provide my own names for most of them.

Please note,  a few of these shaders make heavy use of GPU resources
which may result in jerky motion on "low end" machines. It may still
be possible to use them by reducing their requirements by  adjusting
the values of control parameters in the .fsh files and in some cases
this has specificaly been allowed for,  but other than that you will
have to change the body of the .fsh or simply not use the scene.

The Emu's Modified versions.

In some cases The Emu has modified the shaders rather more than  has
been described above.  These cases can be identified by the addition
of TheEmu to the originator's name to the filenames.  Currently  the
modified versions comprise

  1) A set of modified versions of David Hoskins Cloud Dome which
     circularise the dome and reduce the load on the GPU by  only
     performing the cloud caculation for pixels within the dome's
     image. At the same time the shader has been parameterised to
     allow the number of iterations used to be reduced  when  run 
     on lower powered systems and to also adjust the "cloudiness"
     and speed of the final image. A range scenes using different
     parameters has been provided to suit a  range  of  different
     GPU capabilities.
   
  2) Two versions of the e#21850.0 shader which produces a waving
     coloured diagonal band are provided, one in which the band's
     position is fixed and one where it moves about.

  3) Three versions of shader e#22014.1,  the  original  contained
     code for all three but two were commented out and I have just
     used each in its own shader.