feat: select idle builders by distance to camera

luaui/Widgets/gui_idle_builders.lua

@@ -25,6 +25,9 @@ local setHeight = 0.046
 local maxIcons = 9
 local showRez = true
 local doUpdateForce = true
+local justSelected = false
+local listSorted = {} -- listSorted[unitDefID]: set to nil when idle list is updated, set to true when idleList[unitDefID] is sorted
+local prevCameraPosition -- {posX, posY, posZ}: camera position for sorting idle units, used to have consistent point of reference when right clicking
 
 local leftclick = 'LuaUI/Sounds/buildbar_add.wav'
 local rightclick = 'LuaUI/Sounds/buildbar_click.wav'
@@ -42,12 +45,14 @@ local spGetMouseState = Spring.GetMouseState
 local spGetUnitCommandCount = Spring.GetUnitCommandCount
 local spGetFactoryCommands = Spring.GetFactoryCommands
 local myTeamID = Spring.GetMyTeamID()
+local spGetUnitPosition = Spring.GetUnitPosition
 
 local floor = math.floor
 local ceil = math.ceil
 local min = math.min
 local max = math.max
 local math_isInRect = math.isInRect
+local math_distance2dSquared = math.distance2dSquared
 
 local GL_SRC_ALPHA = GL.SRC_ALPHA
 local GL_ONE = GL.ONE
@@ -294,6 +299,7 @@ local function updateList(force)
 	local prevIdleList = idleList
 	idleList = {}
 	local queue
+	listSorted = {}
 	for unitID, unitDefID in pairs(unitList) do
 		queue = unitConf[unitDefID] and spGetFactoryCommands(unitID, 0) or spGetUnitCommandCount(unitID, 0)
 		if queue == 0 then
@@ -732,12 +738,24 @@ function widget:MousePress(x, y, button)
 								if clicks[unitDefID] then
 									clicks[unitDefID] = clicks[unitDefID] + 1
 								else
-									clicks[unitDefID] = 1
+									clicks[unitDefID] = 0
 								end
 								num = (clicks[unitDefID]) % (#idleList[unitDefID]) + 1
 							end
+							if not listSorted[unitDefID] then
+								-- FIXME: should use center of screen rather than camera
+								local camX, camY, camZ = unpack(prevCameraPosition or {Spring.GetCameraPosition()})
+								prevCameraPosition = {camX, camY, camZ}
+								table.sort(idleList[unitDefID], function (a, b)
+									local unitAX, _, unitAZ = spGetUnitPosition(a)
+									local unitBX, _, unitBZ = spGetUnitPosition(b)
+									return math_distance2dSquared(unitAX, unitAZ, camX, camZ) < math_distance2dSquared(unitBX, unitBZ, camX, camZ)
+								end)
+								listSorted[unitDefID] = true
+							end
 							units = { idleList[unitDefID][num] }
 						end
+						justSelected = true
 						Spring.SelectUnitArray(units)
 					end
 					if button == 3 then
@@ -756,6 +774,13 @@ end
 
 function widget:SelectionChanged(sel)
 	selectedUnits = sel or {}
+	if justSelected then -- ignore selections done by the widget itself 
+		justSelected = false
+		return
+	end
+	prevCameraPosition = nil
+	listSorted = {}
+	clicks = {}
 end