code: public void setDiffuse(float red, float green, float blue){
          diffuse[0] = red;
          diffuse[1] = green;
          diffuse[2] = blue;
          Di = true;
      }
docs: Sets the diffuse color of the materials used for shapes drawn to the screen.
  
  @param red
  The red color of the diffuse.
  @param green
  The green color of the diffuse.
  @param blue
  The blue color of the diffuse.