Make automatic_rotate relative, allow setting rotation (#8468)

automatic_rotate does not make sense if it is absolute. Make it relative.

To avoid bouncing, set_rotation did not update the client when automatic_rotate was set. That's no longer necessary because the new spinning method applies the rotation on top of the current one, and the updates are necessary for set_rotation to actually transform the object.

Co-authored-by: ANAND <ClobberXD@gmail.com>

Co-authored-by: Pedro Gimeno <pgimeno@users.noreply.notabug.org>

doc/lua_api.txt

@@ -6555,6 +6555,7 @@ Player properties need to be saved manually.
 
         automatic_rotate = 0,
         -- Set constant rotation in radians per second, positive or negative.
+        -- Object rotates along the local Y-axis, and works with set_rotation.
         -- Set to 0 to disable constant rotation.
 
         stepheight = 0,

src/client/content_cao.cpp

@@ -1077,10 +1077,13 @@ void GenericCAO::step(float dtime, ClientEnvironment *env)
 			updateTextures(m_previous_texture_modifier);
 		}
 	}
+
 	if (!getParent() && std::fabs(m_prop.automatic_rotate) > 0.001) {
-		m_rotation.Y += dtime * m_prop.automatic_rotate * 180 / M_PI;
-		rot_translator.val_current = m_rotation;
-		updateNodePos();
+		// This is the child node's rotation. It is only used for automatic_rotate.
+		v3f local_rot = node->getRotation();
+		local_rot.Y = modulo360f(local_rot.Y - dtime * core::RADTODEG *
+				m_prop.automatic_rotate);
+		node->setRotation(local_rot);
 	}
 
 	if (!getParent() && m_prop.automatic_face_movement_dir &&
@@ -1501,11 +1504,7 @@ void GenericCAO::processMessage(const std::string &data)
 		m_position = readV3F32(is);
 		m_velocity = readV3F32(is);
 		m_acceleration = readV3F32(is);
-
-		if (std::fabs(m_prop.automatic_rotate) < 0.001f)
-			m_rotation = readV3F32(is);
-		else
-			readV3F32(is);
+		m_rotation = readV3F32(is);
 
 		m_rotation = wrapDegrees_0_360_v3f(m_rotation);
 		bool do_interpolate = readU8(is);