From a401c98c745ce6a3b5cfaffc70de67c3b05becf5 Mon Sep 17 00:00:00 2001
From: Peter Barker <pbarker@barker.dropbear.id.au>
Date: Fri, 27 Sep 2024 11:01:24 +1000
Subject: [PATCH] AP_Terrain: split sending terrain report from terrain request

---
 libraries/AP_Terrain/AP_Terrain.h   |  3 +++
 libraries/AP_Terrain/TerrainGCS.cpp | 19 +++++++++++++------
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/libraries/AP_Terrain/AP_Terrain.h b/libraries/AP_Terrain/AP_Terrain.h
index 9d473a6b30..b0cbe826ab 100644
--- a/libraries/AP_Terrain/AP_Terrain.h
+++ b/libraries/AP_Terrain/AP_Terrain.h
@@ -109,6 +109,9 @@ public:
     void send_request(mavlink_channel_t chan);
 
     // handle terrain data and reports from GCS
+    // send a terrain report for the current location, extrapolating height as we do for navigation:
+    void send_report(mavlink_channel_t chan);
+    // send a terrain report or Location loc
     void send_terrain_report(mavlink_channel_t chan, const Location &loc, bool extrapolate);
     void handle_data(mavlink_channel_t chan, const mavlink_message_t &msg);
     void handle_terrain_check(mavlink_channel_t chan, const mavlink_message_t &msg);
diff --git a/libraries/AP_Terrain/TerrainGCS.cpp b/libraries/AP_Terrain/TerrainGCS.cpp
index e65b874041..e5e9f2ec25 100644
--- a/libraries/AP_Terrain/TerrainGCS.cpp
+++ b/libraries/AP_Terrain/TerrainGCS.cpp
@@ -115,17 +115,12 @@ void AP_Terrain::send_request(mavlink_channel_t chan)
 
     Location loc;
     if (!AP::ahrs().get_location(loc)) {
-        // we don't know where we are. Send a report and request any cached blocks.
+        // we don't know where we are. Request any cached blocks.
         // this allows for download of mission items when we have no GPS lock
-        loc = {};
-        send_terrain_report(chan, loc, true);
         send_cache_request(chan);
         return;
     }
 
-    // always send a terrain report
-    send_terrain_report(chan, loc, true);
-
     // did we request recently?
     if (AP_HAL::millis() - last_request_time_ms[chan] < 2000) {
         // too soon to request again
@@ -207,6 +202,18 @@ void AP_Terrain::handle_data(mavlink_channel_t chan, const mavlink_message_t &ms
     }
 }
 
+/*
+   send a TERRAIN_REPORT for the current location
+ */
+void AP_Terrain::send_report(mavlink_channel_t chan)
+{
+    Location loc;
+    if (!AP::ahrs().get_location(loc)) {
+        loc = {};
+    }
+
+    send_terrain_report(chan, loc, true);
+}
 
 /* 
    send a TERRAIN_REPORT for a location