glm::vec3 VirtualTrackball::getClosestPointOnUnitSphere(int x, int y) {
glm::vec2 normalized_coords;
glm::vec3 point_on_sphere;
float k;
normalized_coords = getNormalizedWindowCoordinates(x, y);
// Finding the point on the sphere
k = sqrtf(normalized_coords.x*normalized_coords.x + normalized_coords.y*normalized_coords.y);
if (k <= 0.5)
{
point_on_sphere.x = 2 * normalized_coords.x;
point_on_sphere.y = 2 * normalized_coords.y;
point_on_sphere.z = sqrtf(1 - 4 * (k * k));
}
else
{
point_on_sphere.x = normalized_coords.x / k;
point_on_sphere.y = normalized_coords.y / k;
point_on_sphere.z = 0;
}
//std::cout << "Point on sphere: " << point_on_sphere.x << ", " << point_on_sphere.y << ", " << point_on_sphere.z << std::endl;
return point_on_sphere;
}
glm::vec3 VirtualTrackball::getClosestPointOnUnitSphere(int x, int y) {
glm::vec2 n_coord = getNormalizedWindowCoordinates(x, y);
glm::vec3 point_on_sphere;
float r, k, z_outside, z_inside;
r = 0.5f; //Radius
k = sqrt( pow2(n_coord.x) + pow2(n_coord.y) ); //square root of x^2 + y^2
z_outside = (pow2(r) / 2.0f) / k; // Z-position outside of circle
z_inside = sqrt( 1.0f - 4.0f * pow2(k)); // Z-position inside of circle
//Mouse is outside of circle
if(k > pow2(r) / 2.0f){
point_on_sphere = glm::vec3( n_coord.x * 2.0f, n_coord.y * 2.0f, z_outside);
}
//Mouse is inside of circle
else{
point_on_sphere = glm::vec3( 2.0f * n_coord.x, 2.0f * n_coord.y, z_inside);
}
return point_on_sphere;
}
