Run results for: Throughput of rectangle overlap calculator

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.167 Safari/537.36

Browser: Chrome 64

Operating system: Mac OS X 10.12.6

Device Platform: Other

Date tested: 2025 years ago

Test name	Executions per second
full overlap check	0.0 Ops/sec
one-side clipping	465947.1 Ops/sec

Script Preparation code:

var max = Math.max.bind(Math);
var min = Math.min.bind(Math);

function between(a, x, b) {
    return a <= x && x <= b;
}

function intersect_1d(start1, end1, start2, end2) {
    const c1 = between(start1, start2, end1) ? 1 : 0;
    const c2 = between(start1, end2,   end1) ? 2 : 0;
    const c3 = between(start2, start1, end2) ? 4 : 0;
    const c4 = between(start2, end1,   end2) ? 8 : 0;
    const _case = c1 | c2 | c3 | c4;

    switch (_case) {
        case 0:  return [NaN, NaN];
        case 1:  return [start2, start2];
        case 2:  return [end2, end2];
        case 3:  return [start2, end2];
        case 4:  return [start1, start1];
        case 5:  return [min(start1, start2), max(start1, start2)];
        case 6:  return [min(start1,   end2), max(start1,   end2)];
        case 7:  return [min(start1, start2), max(start1,   end2)];
        case 8:  return [end1, end1];
        case 9:  return [min(end1,   start2), max(end1,   start2)];
        case 10: return [min(end1,     end2), max(end1,     end2)];
        case 11: return [min(end1,   start2), max(end1,     end2)];
        case 12: return [start1, end1];
        case 13: return [min(start1, start2), max(end1,   start2)];
        case 14: return [min(start1,   end2), max(end1,     end2)];
        case 15: return [start1, end2];
        default: return [NaN, NaN];
    }
}

function intersect_2d(A, B) {
    const [top, bottom] = intersection(A.top, A.bottom, B.top, B.bottom);
    const [left, right] = intersection(A.left, A.right, B.left, B.right);

    if (isNaN(top) || isNaN(bottom) || isNaN(left) || isNaN(right) || (top === bottom) || (left === right)) {
        return [];
    }

    return [{ left, top, right, bottom }];
}

function clip(A, B) {
    var rectangles = []; 

    if (A.top < B.top) {
        rectangles.push({ left: A.left, top: A.top, right: A.right, bottom: B.top }); 
    }
    if (A.left < B.left) {
        rectangles.push({ left: A.left, top: max(A.top, B.top), right: B.left, bottom: min(A.bottom, B.bottom) }); 
    }
    if (A.right > B.right) {
        rectangles.push({ left: B.right, top: max(A.top, B.top), right: A.right, bottom: min(A.bottom, B.bottom) }); 
    }
    if (A.bottom > B.bottom) {
        rectangles.push({ left: A.left, top: B.bottom, right: A.right, bottom: A.bottom }); 
    }

    return rectangles; 
}

function overlap(A, B) {
    const rA =  clip(A, B).map(rect =>  ({ rect, owner: 1 }));
    const rB =  clip(B, A).map(rect =>  ({ rect, owner: 2 }));
    const rAB = intersect_2d(A, B).map(rect => ({ rect, owner: 3 }));

    return rA.concat(rB).concat(rAB);
}

Tests:

full overlap check
overlap({ left: Math.random(), top: Math.random(), right: Math.random(), bottom: Math.random(), }, { left: Math.random(), top: Math.random(), right: Math.random(), bottom: Math.random(), });
one-side clipping
clip({ left: Math.random(), top: Math.random(), right: Math.random(), bottom: Math.random(), }, { left: Math.random(), top: Math.random(), right: Math.random(), bottom: Math.random(), });

Run results for: Throughput of rectangle overlap calculator

full overlap check

one-side clipping