Depth Limit

• The big triangle can be drawn as three small triangles.
• Each small triangle can be drawn as three smaller triangles.
• Each of those smaller triangle can be drawn as three yet smaller triangles.
• Each of those yet smaller triangle can be drawn as three even smaller triangles.
• . . .

The above is done recursively. But somehow the recursion has to end. One way to do this is with a counter that is incremented for each recursive call. When the counter reaches a limit, draw solid triangles and end the recursion. Here is the idea:

class STriangle extends Group
{
  STriangle( Color color, int order, int limit, 
    double x0, double y0, double x1, double y1, double x2, double y2 )
  {
     
    // Calculate midpoints of the three sides
     
    // If the depth limit has not been reached,
    // draw the current triangle as three hollow little triangles
    // recursively using this very method.
    if ( order < limit )
    {
      order++ ;
                // call STriangle for each of three little triangles 
    }
    
    // If the depth limit has been reached,
    // draw the current triangle as three solid little triangles
    else
    {
                // draw three solid triangles 
    }
  
  }
}