Игровая демка "Сапёр" на чистом WebGL 1.0 и JavaScript из туториала "Unity 2D Minesweeper Tutorial" от NoobTuts

var mouseX, mouseY;
function handleMouseDown(e) { 
    mouseX = (e.clientX - canvas.offsetLeft) / SCALE;
    mouseY = (e.clientY - canvas.offsetTop) / SCALE;
    getBodyAtMouse();
}

var selectedBody;
function getBodyAtMouse() {
 mousePVec = new b2Vec2(mouseX, mouseY);
    var aabb = new b2AABB();
    aabb.lowerBound.Set(mouseX - 0.001, mouseY - 0.001);
    aabb.upperBound.Set(mouseX + 0.001, mouseY + 0.001);
    selectedBody = null;
    world.QueryAABB(getBodyCB, aabb);
    if(selectedBody!= null && selectedBody.GetUserData() != null)
              console.log(selectedBody.GetUserData().name);
    return selectedBody;
}

function getBodyCB(fixture) {
       if(fixture.GetShape().TestPoint(fixture.GetBody().GetTransform(), mousePVec)){
                  selectedBody = fixture.GetBody();
    }