// -*- C -*-

// suitable for masking things within radius sqrt(2) only
module FArcSegment_mask(beta) {
  for (i=[0 : 0.75 : 3]) {
    rotate(i*beta/4)
      polygon([[0, 0],
	       [1, 0],
	       [cos(beta/4), sin(beta/4)]]);
  }
}

module FArcSegment(xc,yc,inrad,outrad,alpha,delta) {
  translate([xc,yc]) {
    intersection() {
      difference() {
	circle(r=outrad, $fn=70);
	circle(r=inrad, $fn=70);
      }
      rotate(alpha) scale(outrad*2) {
	FArcSegment_mask(delta);
      }
    }
  }
}

module rectfromto(a,b) {
  ab = b - a;
  translate([min(a[0], b[0]), min(a[1], b[1])])
    square([abs(ab[0]), abs(ab[1])]);
}
module circleat(c,r) { translate(c) circle(r); }
module linextr(z0,z1, convexity=20) {
  translate([0,0,z0])
    linear_extrude(height=z1-z0, convexity=convexity)
    children();
}

module linextr_x_yz(x0,x1, convexity=20) { // XY turn into YZ
  rotate([90,0,0])
    rotate([0,90,0])
    linextr(x0,x1, convexity=convexity)
    children();
}

module linextr_y_xz(y0,y1, convexity=20) { // XY turn into YZ
  rotate([0,0,180])
    rotate([90,0,0])
    linextr(y0,y1, convexity=convexity)
    children();
}