public override void Update(GameTime gameTime)
{
while (TouchPanel.IsGestureAvailable)
{
GestureSample gesture = TouchPanel.ReadGesture();
if (gesture.GestureType == GestureType.FreeDrag)
{
Vector2 b = gesture.Position; // current finger position
Vector2 a = b - gesture.Delta; // previous finger position
Vector3d a3 = camera.GetUnitSphereIntersection(a.X, a.Y);
Vector3d b3 = camera.GetUnitSphereIntersection(b.X, b.Y);
if (a3 != null && b3 != null)
{
UpdateCameraRotation(a3, b3);
}
}
else if (gesture.GestureType == GestureType.Pinch)
{
Vector2 b = gesture.Position; // current finger position
Vector2 a = b - gesture.Delta; // previous finger position
Vector2 d = gesture.Position2; // current finger position
Vector2 c = d - gesture.Delta2; // previous finger position
Vector3d a3 = camera.GetUnitSphereIntersection(a.X, a.Y);
Vector3d b3 = camera.GetUnitSphereIntersection(b.X, b.Y);
Vector3d c3 = camera.GetUnitSphereIntersection(c.X, c.Y);
Vector3d d3 = camera.GetUnitSphereIntersection(d.X, d.Y);
if (a3 != null && b3 != null && c3 != null && d3 != null)
{
// this is likely not 100% accurate pinch, but good enough for awhile
Vector3d avg1 = camera.GetUnitSphereIntersection(a.X / 2 + c.X / 2, a.Y / 2 + c.Y / 2);
Vector3d avg2 = camera.GetUnitSphereIntersection(b.X / 2 + d.X / 2, b.Y / 2 + d.Y / 2);
if (avg1 != null && avg2 != null)
{
double cos1 = a3.Dot(c3);
double sin1 = a3.Cross(c3).Length();
double cos2 = b3.Dot(d3);
double sin2 = b3.Cross(d3).Length();
double angle1 = Math.Atan2(sin2, cos2);
double angle2 = Math.Atan2(sin1, cos1);
double scaleAmount;
if (angle1 < 2 * angle2 && angle1 > 0.5 * angle2) // let's ignore division by zero and extreme zoom for now
{
scaleAmount = angle1 / angle2;
}
else
{
scaleAmount = 1;
}
camera.cameraZoom += Math.Log(scaleAmount, 2);
UpdateCameraRotation(avg1, avg2);
}
}
}
else if (gesture.GestureType == GestureType.Tap)
{
Vector2 a = gesture.Position; // current finger position
Vector3d a3 = camera.GetLatLongOfCoord(a.X, a.Y);
// center on the click and zoom in
if (a3 != null)
{
camera.cameraRotX = a3.X;
camera.cameraRotY = a3.Y;
camera.cameraZoom += 1;
}
}
}
camera.UpdateCamera();
}
