42.20 and Towtrucks

42.20/media/lua/server/BTTow.lua

@@ -3,61 +3,54 @@ BTtow.Create = {}
 BTtow.Init = {}
 
 local TowbarVariantSize = 24
-local TowbarNormalStart = 0
-local TowbarLargeStart = 24
 local TowbarMaxIndex = TowbarVariantSize - 1
-local VanillaScaleMin = 1.5
-local VanillaScaleMax = 2.0
+local TowbarFirstZ = 1.0
+local TowbarSlotStep = 0.1
+-- Measured from Towbar.fbx at its original 0.01 script scale. Keep this in
+-- lockstep with the client selector so the enlarged mesh's inner end remains
+-- on the same vehicle-hitbox contact point.
+local TowbarVisualScale = 2.5
+local TowbarModelLength = 0.9714089036
+local TowbarScaledModelLength = TowbarModelLength * TowbarVisualScale
+local TowbarModelHalfLength = TowbarScaledModelLength / 2
 
-local function getVehicleModelScale(script)
+local function getTowbarFrontEdgeZ(script)
     if not script then return nil end
 
-    local ok, result = pcall(function()
-        return script:getModelScale()
+    local ok, shape = pcall(function()
+        return script:getPhysicsChassisShape()
     end)
-    if ok and type(result) == "number" then
-        return result
-    end
+    if not ok or not shape then return nil end
 
-    ok, result = pcall(function()
-        local model = script:getModel()
-        if model then
-            return model:getScale()
-        end
+    local shapeOk, shapeZ = pcall(function()
+        return shape:z()
+    end)
+    if not shapeOk or type(shapeZ) ~= "number" or shapeZ <= 0 then
         return nil
+    end
+
+    local centerOk, center = pcall(function()
+        return script:getCenterOfMassOffset()
     end)
-    if ok and type(result) == "number" then
-        return result
-    end
+    if not centerOk or not center then return nil end
 
-    return nil
-end
+    local zOk, centerZ = pcall(function()
+        return center:z()
+    end)
+    if not zOk or type(centerZ) ~= "number" then return nil end
 
-local function isVanillaScale(script)
-    local modelScale = getVehicleModelScale(script)
-    if modelScale == nil then
-        return true
-    end
-
-    local configuredMin = TowBarMod and TowBarMod.Config and tonumber(TowBarMod.Config.vanillaTowbarModelScaleMin)
-    local configuredMax = TowBarMod and TowBarMod.Config and tonumber(TowBarMod.Config.vanillaTowbarModelScaleMax)
-    local minScale = configuredMin or VanillaScaleMin
-    local maxScale = configuredMax or VanillaScaleMax
-    return modelScale >= minScale and modelScale <= maxScale
-end
-
-local function getTowbarIndexVanilla(script)
-    local z = script:getPhysicsChassisShape():z() / 2 - 0.1
-    local index = math.floor((z * 2 / 3 - 1) * 10)
-    return math.max(0, math.min(TowbarMaxIndex, index))
+    return centerZ + shapeZ / 2
 end
 
 local function getTowbarModelSlot(script)
-    if not isVanillaScale(script) then
-        -- KI5/small-scale vehicles use the normal towbar0 mesh at Z=1.
-        return 0
-    end
-    return getTowbarIndexVanilla(script)
+    local frontEdgeZ = getTowbarFrontEdgeZ(script)
+    if frontEdgeZ == nil then return nil end
+
+    -- Model offsets position the mesh origin. Move its center outward so the
+    -- towbar's inner end, rather than its center, meets the vehicle hitbox.
+    local modelCenterZ = frontEdgeZ + TowbarModelHalfLength
+    local index = math.floor(((modelCenterZ - TowbarFirstZ) / TowbarSlotStep) + 0.5)
+    return math.max(0, math.min(TowbarMaxIndex, index))
 end
 
 function BTtow.Create.towbar(vehicle, part)  
@@ -81,7 +74,7 @@ function BTtow.Init.towbar(vehicle, part)
         if script then
             local index = getTowbarModelSlot(script)
             local shouldShowOnThisPart = part:getId() == "towbar"
-            if shouldShowOnThisPart then
+            if shouldShowOnThisPart and index ~= nil then
                 part:setModelVisible("towbar" .. index, true)
             end
         end