Fixed Timestep Interpolation (3D)

Adds fixed timestep interpolation to the visual server.
Switchable on and off with project setting.

This version does not add new API for set_transform etc, when nodes have the interpolated flag set they will always use interpolation.

core/local_vector.h

@@ -101,6 +101,22 @@ class LocalVector {
 		}
 	}
 
+	U erase_multiple_unordered(const T &p_val) {
+		U from = 0;
+		U count = 0;
+		while (true) {
+			int64_t idx = find(p_val, from);
+
+			if (idx == -1) {
+				break;
+			}
+			remove_unordered(idx);
+			from = idx;
+			count++;
+		}
+		return count;
+	}
+
 	void invert() {
 		for (U i = 0; i < count / 2; i++) {
 			SWAP(data[i], data[count - i - 1]);

core/math/basis.h

@@ -171,6 +171,7 @@ class _NO_DISCARD_CLASS_ Basis {
 	bool is_rotation() const;
 
 	Basis slerp(const Basis &p_to, const real_t &p_weight) const;
+	_FORCE_INLINE_ Basis lerp(const Basis &p_to, const real_t &p_weight) const;
 
 	operator String() const;
 
@@ -340,4 +341,13 @@ real_t Basis::determinant() const {
 			elements[1][0] * (elements[0][1] * elements[2][2] - elements[2][1] * elements[0][2]) +
 			elements[2][0] * (elements[0][1] * elements[1][2] - elements[1][1] * elements[0][2]);
 }
+
+Basis Basis::lerp(const Basis &p_to, const real_t &p_weight) const {
+	Basis b;
+	b.elements[0] = elements[0].linear_interpolate(p_to.elements[0], p_weight);
+	b.elements[1] = elements[1].linear_interpolate(p_to.elements[1], p_weight);
+	b.elements[2] = elements[2].linear_interpolate(p_to.elements[2], p_weight);
+
+	return b;
+}
 #endif // BASIS_H