/// <summary>
/// Evaluate pos into a color
/// </summary>
/// <param name="pos">Value in range 0.0f-1.0f</param>
/// <param name="color">Color will be interpolated into this</param>
/// <returns></returns>
public void evaluate(float pos, float4 color)
{
if (Stops.Count == 0)
{
color.x = 0.0f;
color.y = 0.0f;
color.z = 0.0f;
color.w = 0.0f;
return;
}
// stop1 = left of pos
var left = Stops[0];
// stop2 = right of pos
ColorStop right = null;
// if there is only one stop, or we're on the left of the very first stop
// just copy the color, we're done.
if (Stops.Count == 1 || pos <= left.Position)
{
color.Copy(left.Color);
}
else
{
// get left and right items
var lr = GetLeftRight(pos);
left = lr.Item1;
right = lr.Item2;
var last_item = lr.Item3;
// if we're on the right of the right stop, copy
// color, we're done.
if (pos >= right.Position)
{
color.Copy(right.Color);
}
else
{
// if we're on constant interpolation, lets use
// color on left of position.
if (Interpolation == Interpolations.Constant)
{
color.Copy(left.Color);
}
else
{
// ok, so we need to interpolate
float mfac;
float fac;
// get factor
if (Math.Abs(left.Position - right.Position) > 0.0001)
{
fac = Math.Abs(pos - right.Position) / Math.Abs(left.Position - right.Position);
}
else
{
fac = last_item ? 1.0f : 0.0f;
}
// extra easing if ease
if (Interpolation == Interpolations.Ease)
{
mfac = fac * fac;
fac = 3.0f * mfac - 2.0f * mfac * fac;
}
// right color fac
mfac = 1.0f - fac;
// factor colors
left.Color *= fac;
right.Color *= mfac;
// add factored colors to get new interpolated color
var interpolated_color = left.Color + right.Color;
// copy, done
color.Copy(interpolated_color);
}
}
}
}
