Refactor grapple to use rigid, unbreakable Verlet rope physics

Implements a new grapple rope system based on pure Verlet constraints for robust, non-stretchy behavior.

- Overhauls rope physics, removing old spring/force systems and stretch mechanics.
- Makes the rope virtually unbreakable with an extremely high tension threshold (500% stretch).
- Centralizes rope length control and simplifies related logic.
- Enhances actor and target MO protection systems to ensure stability with the new rigid physics.
- Updates debug rendering to display detailed rope state information.

Make grapple rope rigid and virtually unbreakable

Replaces the previous spring-based system with a pure Verlet constraint model, resulting in a non-stretchy and highly robust rope.
The rope is now virtually unbreakable, only snapping at an extremely high tension threshold (500% stretch).
Rope length control is centralized and simplified.
Actor and target MO protection systems are enhanced to ensure stability with the new rigid physics.
Debug rendering is updated to display detailed rope state information.

Author: OpenTools-run

Data/Base.rte/Devices/Tools/GrappleGun/Grapple.lua

@@ -23,11 +23,11 @@ function Create(self)
     self.fireVel = 40      -- This immediately overwrites the .ini FireVel
     self.maxLineLength = 400   -- Shorter rope for faster gameplay
     self.setLineLength = 0
-    self.lineStrength = 40 -- How much "force" the rope can take before breaking
+    self.lineStrength = 10000 -- EXTREMELY HIGH force threshold - virtually unbreakable (was 120)
 
     self.limitReached = false
-    self.stretchMode = false   -- Alternative elastic pull mode a là Liero
-    self.stretchPullRatio = 0.01 -- How much the rope stretches when pulling in stretch mode
+    self.stretchMode = false   -- Disabled for rigid rope behavior
+    self.stretchPullRatio = 0.0 -- No stretching allowed for rigid rope
     self.pieSelection = 0  -- 0 is nothing, 1 is full retract, 2 is partial retract, 3 is partial extend, 4 is full extend
 
     self.climbDelay = 8    -- Faster climbing for shorter rope
@@ -45,17 +45,14 @@ function Create(self)
     -- Rope physics variables from VelvetGrapple
     self.currentLineLength = 0
     self.longestLineLength = 0
-    self.cablespring = 0.15 -- VelvetGrapple constraint stiffness
+    self.cablespring = 0.01 -- Very low for completely rigid rope behavior (was 0.05)
 
     -- Dynamic rope segment calculation variables
     self.minSegments = 1   -- Minimum number of segments
     self.maxSegments = 500  -- Maximum number of segments
     self.segmentLength = 12 -- Target length per segment (increased for better performance)
     self.currentSegments = self.minSegments -- Current number of segments
 
-    -- Verlet physics friction for stability
-    self.usefriction = 0.99 -- Matches VelvetGrapple
-    
     -- Mousewheel control variables
     self.shiftScrollSpeed = 8.0 -- Faster rope control with Shift+Mousewheel
 
@@ -125,9 +122,9 @@ function Update(self)
 				self.ToDelete = false
 				self.ToSettle = false
 
-				-- Make sure we have a minimum viable rope length to avoid issues
-				if self.actionMode == 1 and self.currentLineLength < 1 then
-					self.currentLineLength = math.max(1, SceneMan:ShortestDistance(self.parent.Pos, self.Pos, self.mapWrapsX).Magnitude)
+				-- Make sure we have valid rope data, but allow zero length
+				if self.actionMode == 1 and self.currentLineLength < 0 then
+					self.currentLineLength = 0 -- Allow zero length compression
 				end
 
 				-- Update line length when in flight
@@ -172,8 +169,20 @@ function Update(self)
 					-- Attached mode - run full physics simulation
 					RopePhysics.updateRopePhysics(self, startPos, endPos, self.currentLineLength)
 
-					-- Apply constraints to maintain rope structure and length
-					RopePhysics.applyRopeConstraints(self, self.currentLineLength)
+					-- Apply constraints and check for rope breaking (extremely high threshold)
+					local ropeBreaks = RopePhysics.applyRopeConstraints(self, self.currentLineLength)
+					if ropeBreaks or self.shouldBreak then
+						-- Rope snapped due to EXTREME tension (500% stretch)
+						self.ToDelete = true
+						if self.parent and self.parent:IsPlayerControlled() then
+							-- Add screen shake and sound effect when rope breaks
+							FrameMan:SetScreenScrollSpeed(10.0) -- More dramatic shake for extreme break
+							if self.returnSound then
+								self.returnSound:Play(self.parent.Pos)
+							end
+						end
+						return -- Exit early since rope is breaking
+					end
 				end
 
 				-- Special handling for attached targets (MO grabbing)
@@ -205,13 +214,6 @@ function Update(self)
 
 				-- Draw the rope using the renderer module
 				RopeRenderer.drawRope(self, player)
-				
-				-- Show rope tension indicator when necessary
-				RopeRenderer.showTensionIndicator(self, player)
-				
-				-- Show debug info temporarily to help diagnose issues
-				local debugPos = self.Pos + Vector(10, -30) -- Define a position for debug text
-				RopeRenderer.showDebugInfo(self, player, debugPos)
 
 				-- Update lineVec and lineLength based on current positions
 				self.lineVec = SceneMan:ShortestDistance(self.parent.Pos, self.Pos, self.mapWrapsX)
@@ -223,17 +225,29 @@ function Update(self)
 					self.Pos.Y = self.apy[self.currentSegments]
 				end
 
-				-- Update current line length based on action mode
+				-- Update current line length based on action mode - CENTRALIZED CONTROL
 				if self.actionMode == 1 and self.limitReached == false then 
 					-- Always update rope length while in flight - rope should be tight
 					self.currentLineLength = self.lineLength 
+					self.setLineLength = self.currentLineLength
 				elseif self.actionMode > 1 then
-					-- When attached, maintain set line length for physics constraints
-					-- currentLineLength should only be updated by player input or automatic climbing
+					-- When attached, currentLineLength is controlled by input/auto-climbing
+					-- Ensure it stays within bounds
+					self.currentLineLength = math.max(10, math.min(self.currentLineLength, self.maxLineLength))
+					self.setLineLength = self.currentLineLength
 				end
 
-				-- Check if line length exceeds maximum
-				RopeStateManager.checkLineLengthUpdate(self)
+				-- Single length limit check - removed redundant checkLineLengthUpdate call
+				if self.currentLineLength > self.maxLineLength then
+					self.currentLineLength = self.maxLineLength
+					self.setLineLength = self.maxLineLength
+					if not self.limitReached then
+						self.limitReached = true
+						self.clickSound:Play(self.parent.Pos)
+					end
+				else
+					self.limitReached = false
+				end
 
 				if self.parentGun and self.parentGun.ID ~= rte.NoMOID then
 					self.parent = ToMOSRotating(MovableMan:GetMOFromID(self.parentGun.RootID))
@@ -340,15 +354,12 @@ function Update(self)
 					-- Process input based climbing
 					RopeInputController.handleRopePulling(self)
 
-					-- Process terrain pull physics
-					if self.actionMode == 2 and RopeStateManager.applyTerrainPullPhysics(self) then
-						self.ToDelete = true
-					end
+					-- DISABLE force-based physics - using pure Verlet constraint system instead
+					-- The RopePhysics.applyRopeConstraints handles all position constraints
+					-- No need for additional spring forces that conflict with rigid constraints
 
-					-- Process MO pull physics
-					if self.actionMode == 3 and RopeStateManager.applyMOPullPhysics(self) then
-						self.ToDelete = true
-					end
+					-- UNBREAKABLE ROPE: No automatic unhooking due to target destruction
+					-- Rope remains attached even if target MO is destroyed for maximum persistence
 				end
 
 				-- Check if we should unhook via double-tap mechanic

Data/Base.rte/Devices/Tools/GrappleGun/Scripts/RopeInputController.lua

@@ -1,5 +1,6 @@
 -- Grapple Gun Input Controller Module
--- Handles all user input related to grapple rope control
+-- Handles user input for rope control with pure constraint-based physics
+-- No velocity manipulation, no force application - only rope length control
 
 local RopeInputController = {}
 
@@ -134,18 +135,10 @@ function RopeInputController.handleDirectionalControl(grappleInstance, controlle
 
     if controller:IsMouseControlled() == false then
         if controller:IsState(Controller.HOLD_UP) then
-            if grappleInstance.currentLineLength > grappleInstance.climbInterval and terrCheck == false then
+            if grappleInstance.currentLineLength > grappleInstance.climbInterval then
                 grappleInstance.climb = 1
-            elseif terrCheck ~= false then
-                -- Try to nudge past terrain
-                local nudge = math.sqrt(grappleInstance.lineLength + grappleInstance.parent.Radius) / 
-                             (10 + grappleInstance.parent.Vel.Magnitude)
-                local aimvec = Vector(grappleInstance.lineVec.Magnitude, 0)
-                               :SetMagnitude(nudge)
-                               :RadRotate((grappleInstance.lineVec.AbsRadAngle + 
-                                         grappleInstance.parent:GetAimAngle(true))/2 + 
-                                         grappleInstance.parent.FlipFactor * 0.7)
-                grappleInstance.parent.Vel = grappleInstance.parent.Vel + aimvec
+                -- Pure position-based system - no direct velocity manipulation
+                -- Terrain obstacles are handled by Verlet constraint system
             end
         end
 
@@ -260,24 +253,14 @@ function RopeInputController.handleAutoRetraction(grappleInstance, terrCheck)
         grappleInstance.climbTimer:Reset()
 
         if grappleInstance.pieSelection == 0 and grappleInstance.parentGun:IsActivated() then
-            if grappleInstance.currentLineLength > grappleInstance.autoClimbIntervalA and terrCheck == false then
+            if grappleInstance.currentLineLength > grappleInstance.autoClimbIntervalA then
                 grappleInstance.currentLineLength = grappleInstance.currentLineLength - (grappleInstance.autoClimbIntervalA/parentForces)
                 grappleInstance.setLineLength = grappleInstance.currentLineLength
+                -- Pure position-based system - no velocity manipulation or terrain nudging
+                -- Verlet constraints handle all physical interactions
             else
                 grappleInstance.parentGun:RemoveNumberValue("GrappleMode")
                 grappleInstance.pieSelection = 0
-                
-                if terrCheck ~= false then
-                    -- Try to nudge past terrain
-                    local nudge = math.sqrt(grappleInstance.lineLength + grappleInstance.parent.Radius) / 
-                                 (10 + grappleInstance.parent.Vel.Magnitude)
-                    local aimvec = Vector(grappleInstance.lineVec.Magnitude, 0)
-                                  :SetMagnitude(nudge)
-                                  :RadRotate((grappleInstance.lineVec.AbsRadAngle + 
-                                            grappleInstance.parent:GetAimAngle(true))/2 + 
-                                            grappleInstance.parent.FlipFactor * 0.7)
-                    grappleInstance.parent.Vel = grappleInstance.parent.Vel + aimvec
-                end
             end
         end
     end
@@ -288,9 +271,10 @@ function RopeInputController.handleAutoRetraction(grappleInstance, terrCheck)
 
         if grappleInstance.pieSelection == 1 then
             -- Full retract
-            if grappleInstance.currentLineLength > grappleInstance.autoClimbIntervalA and terrCheck == false then
+            if grappleInstance.currentLineLength > grappleInstance.autoClimbIntervalA then
                 grappleInstance.currentLineLength = grappleInstance.currentLineLength - (grappleInstance.autoClimbIntervalA/parentForces)
                 grappleInstance.setLineLength = grappleInstance.currentLineLength
+                -- Pure position-based system - no terrain checking or velocity manipulation
             else
                 grappleInstance.pieSelection = 0
             end