fix: small island save

When compaction is enabled we only save the start and end
of a row, except when it isn't straight, for instance
because it is bypassing an island. For those rows, we now
save all waypoints.

scripts/Course.lua

@@ -1473,14 +1473,51 @@ function Course:getProgress(ix)
     return self.waypoints[ix].dToHere / self.length, ix, ix == #self.waypoints
 end
 
+--- When compaction is enabled we only save the start and end of a row, except when it isn't straight, for instance
+--- because it is bypassing an island. For those rows, we save all waypoints.
+--- Baseline edge courses (with rows following a curved field edge) have the compaction disabled anyway.
+---@return number, number index of next unsaved waypoint, index of next waypoint entry in the XML file
+local function saveRowToXml(waypoints, xmlFile, key, compact, rowStartIx, xmlIx)
+    local row = {}
+    local i, straight, rowAngle = rowStartIx, true, waypoints[rowStartIx].angle
+    while i <= #waypoints and not waypoints[i]:isRowEnd() do
+        table.insert(row, waypoints[i])
+        if math.abs(waypoints[i].angle - rowAngle) > 0.01 then
+            straight = false
+        end
+        i = i + 1
+    end
+    -- i points to the row end, add it to the row
+    local rowEndIx = i
+    table.insert(row, waypoints[i])
+    if straight and compact then
+        -- only save the row start and end
+        waypoints[rowStartIx]:setXmlValue(xmlFile, key, xmlIx)
+        waypoints[rowEndIx]:setXmlValue(xmlFile, key, xmlIx + 1)
+        return rowEndIx + 1, xmlIx + 2
+    else
+        i = xmlIx
+        -- save all waypoints
+        for _, wp in ipairs(row) do
+            wp:setXmlValue(xmlFile, key, i)
+            i = i + 1
+        end
+        return rowEndIx + 1, i
+    end
+end
+
 ---@param compact boolean skip waypoints between row start and end (as for straight rows, these can be regenerated
 --- easily after the course is loaded)
 local function saveWaypointsToXml(waypoints, xmlFile, key, compact)
-    local i = 1
-    for _, wp in ipairs(waypoints) do
-        if not compact or (not wp:getRowNumber() or wp:isRowStart() or wp:isRowEnd()) then
-            wp:setXmlValue(xmlFile, key, i)
-            i = i + 1
+    local wpIx, xmlIx = 1, 1
+    while wpIx <= #waypoints do
+        local wp = waypoints[wpIx]
+        if wp:isRowStart() then
+            wpIx, xmlIx = saveRowToXml(waypoints, xmlFile, key, compact, wpIx, xmlIx)
+        else
+            wp:setXmlValue(xmlFile, key, xmlIx)
+            wpIx = wpIx + 1
+            xmlIx = xmlIx + 1
         end
     end
 end