varying vec4 varColor;
uniform vec4 uniColors[4];
void main ()
{
  vec4 col;
  gl_Position = gl_Vertex;
  col = max (vec4(0.0, 0.0, 0.0, 0.0), uniColors[0]);
  col = (col + max (vec4(0.0, 0.0, 0.0, 0.0), uniColors[1]));
  col = (col + max (vec4(0.0, 0.0, 0.0, 0.0), uniColors[2]));
  col = (col + max (vec4(0.0, 0.0, 0.0, 0.0), uniColors[3]));
  varColor = col;
}