From 4db50617ca7ba9aeb83fe64f26eb93ed2a424aae Mon Sep 17 00:00:00 2001
From: Julian Smith <jules@op59.net>
Date: Fri, 29 Jan 2021 16:48:13 +0000
Subject: [PATCH] Added 'Still View', a new core view, number 8.

This view is like Helicopter View except that it does not change the view
heading to match the aircraft, which makes it work much better for vertical
flight, e.g. with the shuttle.

The new view is disabled by default.

Nasal/view.nas
    contains the new view config.
defaults.xml:
    Added view 8 to list of views for which we default to Helicopter view's
    target offsets (so that they look at the centre of the aircraft).
---
 Nasal/view.nas |  4 ++--
 defaults.xml   | 13 +++++++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/Nasal/view.nas b/Nasal/view.nas
index 7a78e58d0..0dc47a83c 100644
--- a/Nasal/view.nas
+++ b/Nasal/view.nas
@@ -276,7 +276,7 @@ var manager = {
                     # this allows Tower View AGL to work on aircraft that don't
                     # know about it but need non-zero target-*-offset-m values
                     # to centre the view on the middle of the aircraft.
-                    if (i==2 or i==3 or i==5 or i==7) {
+                    if (i==2 or i==3 or i==5 or i==7 or i==8) {
                         set_default(helicopter_view, "config/target-x-offset-m", viewnode);
                         set_default(helicopter_view, "config/target-y-offset-m", viewnode);
                         set_default(helicopter_view, "config/target-z-offset-m", viewnode);
@@ -963,7 +963,7 @@ var fdm_init_listener = setlistener("/sim/signals/fdm-initialized", func {
 	var zoffset = nil;
 	foreach (var v; views) {
 		var index = v.getIndex();
-		if (index > 7 and index < 100) {
+		if (index > 8 and index < 100) {
 			globals["view"] = nil;
 			die("\n***\n*\n*  Illegal use of reserved view index "
 					~ index ~ ". Use indices >= 100!\n*\n***");
diff --git a/defaults.xml b/defaults.xml
index f99437f42..e6e848057 100644
--- a/defaults.xml
+++ b/defaults.xml
@@ -708,6 +708,19 @@ Started September 2000 by David Megginson, david@megginson.com
         <lookat-agl-damping type="double">2.2</lookat-agl-damping>
       </config>
     </view>
+    <view>
+      <!-- Similar to Helicopter View but does not change heading with
+      aircraft, which avoide poor behaviour with vertical climbs, e.g. with
+      Shuttle. -->
+      <name>Still View</name>
+      <enabled type="bool" userarchive="y">false</enabled>
+      <type>lookat</type>
+      <config>
+        <from-model type="bool">false</from-model>
+        <at-model type="bool">true</at-model>
+        <z-offset-m alias="/sim/chase-distance-m"/>
+      </config>
+    </view>    
     <menubar>
       <visibility type="bool" userarchive="y">true</visibility>
       <default include="gui/menubar.xml"/>