Migrating from Spring

While Recoil is mostly compatible with Spring 105 some divergences naturally developed over time.

Here we list the most relevant breaking changes and how to fix them when migrating from Spring.

Table of contents


Font rendering

Rendering fonts now obeys GL color state. This means that sometimes text will not be the same color as previously. To get back previous behaviour, you might need to add gl.Color in front of gl.Text calls. Alternatively, you can add inline colour codes (\255\rrr\ggg\bbb).

Spring.Marker usage

All three Spring.Marker functions (Point, Line, Erase) no longer accept numerical 0 as false for onlyLocal (now follows regular Lua language rules where 0 is true). To get back old behaviour, change 0 to false, e.g.:

-Spring.MarkerAddPoint(x, y, z, text, 0)
+Spring.MarkerAddPoint(x, y, z, text, false)
-Spring.MarkerAddLine(x1, y1, z1, x2, y2, z2, 0, playerId)
+Spring.MarkerAddLine(x1, y1, z1, x2, y2, z2, false, playerId)
-Spring.MarkerErasePosition(x, y, z, noop, 0, playerId)
+Spring.MarkerErasePosition(x, y, z, noop, false, playerId)

Spring.GetConfig usage

Spring.GetConfigInt, Spring.GetConfigFloat and Spring.GetConfigString now accept nil as the second argument (what to return by default if not set). Previously it was treated as 0 (Int and Float) or “” (String). To get back previous behaviour:

local originalGetConfigInt = Spring.GetConfigInt
Spring.GetConfigInt = function(key, def)
 return originalGetConfigInt(key, def) or 0


The tables returned by Spring.GetSelectedUnitsSorted and Spring.GetSelectedUnitsCounts no longer have an additional n key with corresponding value containining the number of unitdefs.

Instead use the second return value, e.g.:

- local counts = Spring.GetSelectedUnitsCounts()
- local unitDefsCount = counts.n
- counts.n = nil
+ local counts, unitDefsCount = Spring.GetSelectedUnitsCounts()

Stop command on manual share

Manually shared units no longer receive the Stop command. Replicate the previous behaviour via the UnitGiven callin:

function wupget:UnitGiven(unitID, unitDefID, newTeam)
	if newTeam == Spring.GetMyTeamID() then -- if doing in unsynced
		Spring.GiveOrderToUnit(unitID, CMD.STOP, 0, 0)


  • Hovercraft and ships brought out of water no longer forced to be upright. To get back previous behaviour, put the upright = true tag in all unit defs whose move def is of the hovercraft or ship type.
  • Units with useFootPrintCollisionVolume but no collisionVolumeScales set will now use the footprint volume (previously mistakenly used the model’s sphere).

    To keep the old hitvolume, set useFootPrintCollisionVolume to false for units with no collisionVolumeScales. Assuming you apply lowerkeys to unit defs, this can also be achieved by putting the following in unit defs post-processing:

    for unitDefID, unitDef in pairs(UnitDefs) do
      if not unitDef.collisionvolumescales then
        unitDef.usefootprintcollisionvolume = nil
  • Tree feature defs treetype0 through treetype16 are now provided by the basecontent archive instead of the engine.

    No known games ship their own basecontent and they would know what to do if so.

  • The firestarter weapon tag no longer capped at 10000 in defs (which becomes 100 in Lua WeaponDefs after rescale), now uncapped.

    To get back previous behaviour, put the following in weapon defs post-processing:

    for weaponDefID, weaponDef in pairs(WeaponDefs) do
      if weaponDef.firestarter then
        weaponDef.firestarter = math.min(weaponDef.firestarter, 10000)
  • It is heavily recommended to replace acceleration and brakeRate with maxAcc and maxDec respectively (possibly in post-processing). While the old spelling still works the way it always did, at some point in the future it will be changed from elmo/frame to elmo/second.

Camera modifiers

The following keyboard modifiers were unhardcoded from engine:

  • On spring camera: rotating on the x (pitch) or y (yaw) axis with ALT and middle mouse button pressed while moving the cursor.
  • Resetting camera settings on ALT pressed and mousewheelscroll down.
  • Rotating on the x axis (pitch) with CTRL pressed and mousewheelscroll.

If games and players do not change engine defaults, no action is needed, however to enable these modifiers as previously the following keybindings must be set:

bind Any+ctrl movetilt   // rotates the camera over the x axis on mousewheel move
bind Any+alt  movereset  // resets camera state to maxzoom/minzoom on mousewheel move, additionally resets tilt on Overhead cam
bind Any+alt  moverotate // rotates the camera in x and y axis on mmb move (Spring cam)

Resurrecting units

Resurrecting units no longer overrides their health to 5%. To get back the old behaviour define a gadget with the following callin:

function gadget:UnitCreated(unitID, unitDefID, teamID, builderID)
  if builderID and Spring.GetUnitWorkerTask(builderID) == CMD.RESURRECT then
    Spring.SetUnitHealth(unitID, Spring.GetUnitHealth(unitID) * 0.05)

VFS mapping API

Spring.MapArchive and Spring.UnmapArchive have been temporarily removed due to sync unsafety. In the meantime, use Spring.UseArchive. These functions are going to come back at some point, but there is no concrete timeline for that yet.

Iterating synced proxy tables

Functions for iterating synced proxy tables: snext, spairs and sipairs have been removed. These have been able to be replaced by the regular next, pairs and ipairs for some time already (so the change can be done before migrating):

 local syncedProxyTable = SYNCED.foo
-for key, value in spairs(syncedProxyTable) do
+for key, value in  pairs(syncedProxyTable) do


  • Paletted image files are no longer accepted. Convert your images not to be paletted.
  • The return value from the UnitUnitCollision callin is now ignored and there is only one event for each collision. There is no way to get back the old behaviour for now, but if someone needs it it could be arranged.
  • Removed the following constants:
    • Platform.glSupport16bitDepthBuffer
    • Platform.glSupport24bitDepthBuffer
    • Platform.glSupport32bitDepthBuffer

    To get back previous behaviour, replace with

    Platform.glSupportDepthBufferBitDepth >= 16 -- or 24, or 32, respectively
  • Removed LOD rendering (2D unit billboards when zoomed out far), including the /distdraw command and the UnitLodDist springsettings entry
  • Removed the AdvSky springsetting and the /dynamicsky command, which made clouds move across the sky. You cannot easily get back previous behaviour, though you can probably achieve something similar by rendering moving clouds yourself.
  • The deprecated Game.allowTeamColors, whose value was always true, has been removed. Note that this inverts logic if you used it like a bool.
  • The default /screenshot format was changed to PNG. Check any automated processing you do on these.
  • Screenshots and replay demo files now have a different filename format, with an UTC timestamp. Check any automated file parsing you might have.