circle intersection

docs/chapters/projections/project.js

@@ -1,3 +1,5 @@
+import refineBinary from "./refine-binary.js";
+
 let curve;
 
 setup() {
@@ -61,56 +63,12 @@ showCandidateInterval(x, y, LUT, i) {
 }
 
 drawProjection(x, y, LUT, i) {
-  let B = this.refineBinary(x, y, LUT, i);
+  let B = refineBinary(curve, x, y, LUT, i);
   setColor(`rgba(100,100,255)`);
   circle(B.x, B.y, 3);
   line(B.x, B.y, x, y);
 }
 
-/*
-  We already know that LUT[i1] and LUT[i2] are *not* good distances,
-  so we know that a better distance will be somewhere between them.
-  We generate three new points between those two, so we end up with
-  five points, and then check which three of those five are a new,
-  better, interval to check within.
-*/
-refineBinary(x, y, LUT, i) {
-  let q, count=1, distance = Number.MAX_SAFE_INTEGER;
-
-  do {
-    let i1 = i === 0 ? 0 : i-1,
-        i2 = i === LUT.length - 1 ? LUT.length -1 : i+1,
-        t1 = LUT[i1].t,
-        t2 = LUT[i2].t,
-        lut = [],
-        step = (t2 - t1)/5;
-
-    if (step < 0.001) break;
-
-    lut.push(LUT[i1]);
-    for(let j=1; j<=3; j++) {
-      let n = curve.get(t1 + j *step);
-      n.distance = dist(n.x, n.y, x, y);
-      if (n.distance < distance) {
-        distance = n.distance;
-        q = n;
-        i = j;
-      }
-      lut.push(n);
-    }
-    lut.push(LUT[i2]);
-
-    // update the LUT to be our new five point LUT, and run again.
-    LUT = lut;
-
-    // The "count" test is mostly a safety measure: it will
-    // never kick in, but something that _will_ terminate is
-    // always better than while(true). Never use while(true)
-  } while (count++ < 25);
-
-  return q;
-}
-
 onMouseMove() {
   redraw();
 }