----------------------------------------------
Shader description files 
----------------------------------------------

Coming soon.

Notes:

- Extention .cl (not OpenCL files, but to use syntax highlighting e.g. in
  spyder) ...

- RGB(A) color values (tuples) in `ShaderParamNames` must contain `RGB` 
  (or `rgb`) to enable QDS scaling the colors to the set color mode.



This is an example shader description file:

.. code-block:: cpp

   //#QDS ShaderName          =SINE_WAVE_GRATING
   //#QDS ShaderParamNames    =perLen_um; perDur_s; minRGB; maxRGB
   //#QDS ShaderParamLengths  =1;1;4;4
   //#QDS ShaderParamDefaults =0.0; 1.0; (0,0,0,255); (255,255,255,255)
   //
   //#QDS ShaderVertexStart
   // ----------------------------------------------------------------------
   void main() 
   {
     gl_Position    = ftransform();
   }
   // ----------------------------------------------------------------------
   //#QDS ShaderVertexEnd

   //#QDS ShaderFragmentStart
   // ----------------------------------------------------------------------
   #define pi    3.141592653589
   #define pi2   6.283185307179

   out    vec4   FragColor;

   uniform float time_s;
   uniform vec3  obj_xy_rot;
   uniform float perLen_um;
   uniform float perDur_s;
   uniform vec4  minRGB;
   uniform vec4  maxRGB;

   float         inten;
   vec4          b;
      
   void main() {
     vec4  a     = gl_FragCoord;
     a.x         = a.x -obj_xy_rot.x;
     a.y         = a.y -obj_xy_rot.y;
     b.x         = a.x*cos(obj_xy_rot[2]) -a.y*sin(obj_xy_rot[2]);
     b.y         = a.y*cos(obj_xy_rot[2]) +a.x*sin(obj_xy_rot[2]);
     inten       = (sin(((b.x)/perLen_um +time_s/perDur_s) *pi2) +1.0)/2.0;
     FragColor   = mix(minRGB, maxRGB, inten);
   }
   // ----------------------------------------------------------------------
   //#QDS ShaderFragmentEnd