interpolation.md

interpolation

//f + (t -f) * a

function interpolateTriangleSide(from, to, mouse)
{
    var percentY = (mouse.y - to.y) / (from.y - to.y);
    
    console.log(percentY);
    
    var cX = from.x + (to.x - from.x) * percentY;
    
    return cX;
}

var from = {
    x : 100,
    y : 600
};

var to = {
    x : 0,
    y : 0
};

var mouse = {
    x : 900,
    y : 150
};

console.log(interpolateTriangleSide(from, to, mouse));

---

check outside (khanacademy)

var p = {
    x : 228,
    y : 226
};

ellipse(p.x, p.y, 10, 10);

var scnd = {
    x : 100, y: 200
};
var first = {
    x : 200, y: 200
};
var third = {
    x : 150, y: 100
};

var baseX = first.x - scnd.x;
var baseY = first.y;

var left = p.x < scnd.x + (baseX / 2);


var interpolateTriangleSide = function(from, to, mousee) {
    var percentY = (mousee.y - to.y) / (from.y - to.y);

    var cX = to.x + (from.x - to.x) * percentY;

    return cX;
};

if(p.y > scnd.y)
{
    //Bottom
    
    if(p.x > scnd.x && p.x < first.x)
    {
        //Bottom, middle
        p = {
            x : p.x,
            y : scnd.y
        }; 
    }
    else
    {
        //Bottom, lock to either left or right
        if(left)
        {
            p = {
                x : scnd.x,
                y : scnd.y
            };
        }
        else
        {
            p = {
                x : first.x,
                y : first.y
            };
        }     
    }
}
else if(p.y < third.y)
{
    //Top
    p = {
        x : third.x,
        y : third.y
    };
}
else if(p.y <= scnd.y)
{
    //Middle, interpolation
    var cX;
    
    if(left) {
        cX = interpolateTriangleSide(scnd, third, p);
    }
    else {
        cX = interpolateTriangleSide(first, third, p);
    }
    
    println(cX + ", " + scnd.x);
    p.x = cX;
}

triangle(first.x, first.y, scnd.x, scnd.y, third.x, third.y);

ellipse(p.x, p.y, 5, 5);