Add initial prototype.

3-mid/physics/interface/source/motor/physics-motor-spring-angular.ads

@@ -0,0 +1,29 @@
+
+with Math;
+
+
+
+package physics.Motor.spring.angular is
+
+   -- a spring which operates in 3 degrees of rotational motion to keep a Solid in a desired attitude.
+
+
+   use type math.Real;
+
+   type Item is new physics.Motor.spring.item with
+      record
+         desiredForward : math.Vector_3 := (0.0, 0.0, -1.0);   -- the Motor's desired forward direction, part of the desired orientation.
+         desiredUp      : math.Vector_3 := (0.0, 1.0,  0.0);   -- the Motor's desired up      direction.
+         desiredRight   : math.Vector_3 := (1.0, 0.0,  0.0);   -- the Motor's desired right   direction.
+
+         angularKd      : math.Real := 0.000_1;    -- the damping constant for angular mode.
+         angularKs      : math.Real := 1.0;        -- the spring  constant for angular mode.
+      end record;
+
+
+
+
+   procedure update (Self : in out Item);
+
+
+end physics.Motor.spring.angular;