{

mplot::Visual v(1024, 768, "Slerping");

v.lightingEffects (true);

// A is the end location coordinate arrows (darker)

sm::vec<float> offset = {};

auto cavm = std::make_unique<mplot::CoordArrows<>> (offset);

cavm->set_parent (v.get_id());

cavm->x_axis_col = mplot::colour::maroon;

cavm->y_axis_col = mplot::colour::darkgreen;

cavm->z_axis_col = mplot::colour::midnightblue;

cavm->finalize();

auto cA = v.addVisualModel (cavm);

// B is the starting location coordinate arrows (lighter)

cavm = std::make_unique<mplot::CoordArrows<>> (offset);

cavm->set_parent (v.get_id());

cavm->x_axis_col = mplot::colour::firebrick1;

cavm->y_axis_col = mplot::colour::palegreen3;

cavm->z_axis_col = mplot::colour::steelblue1;

cavm->finalize();

auto cB = v.addVisualModel (cavm);

cavm = std::make_unique<mplot::CoordArrows<>> (offset);

cavm->set_parent (v.get_id());

cavm->finalize();

auto cC = v.addVisualModel (cavm);

// Define A's location as a viewmatrix. Apply a rotation (first) then a translation

sm::mat<float, 4> A;

A.translate (sm::vec<float>{0.2,0.4,0});

A.rotate (sm::vec<float>::uy(), sm::mathconst<float>::pi_over_4);

// The starting location.

sm::mat<float, 4> B;

B.translate (sm::vec<float>{1,1,1});

B.rotate (sm::vec<float>::uz(), sm::mathconst<float>::pi_over_2);

// From A and B find the pure translation between the two

sm::vec<float> delta_x = A.translation() - B.translation();

// Compute the pre-translation rotations

sm::mat<float, 4> A0 = A;

A0.translate (-A.translation());

sm::mat<float, 4> B0 = B;

B0.translate (-B.translation());

sm::quaternion<float> rA = A0.rotation();

sm::quaternion<float> rB = B0.rotation();

// Set the viewmatrix for both A and B coordinate arrows (these will stay fixed)

cA->setViewMatrix (A);

cB->setViewMatrix (B);

int count = 0;

while (!v.readyToFinish()) {

v.render();

v.wait (0.018);

float prop = static_cast<float>(count++ % 100) / 100.0f;

// Compute the intermediate translation and rotation, C and apply this to the cC coordinate arrows

sm::mat<float, 4> C;

// C is a rotation of the intermediate rotation between rA and rB, then a translation to B +

// the intermediate delta_x:

C.translate (B.translation() + prop * delta_x);

C.rotate (rB.slerp (rA, prop));

cC->setViewMatrix (C);

}