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Revision as of 20:36, 10 February 2010 by Eric5h5 (Talk | contribs)

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Author: Eric Haines (Eric5h5)


This is an enhanced version of the FPSWalker script found in Standard Assets. It allows for both walking and running (either by toggle or by holding down a run key), the capability of detecting falling distances, optionally sliding down slopes (both those above the Slope Limit and/or objects specifically tagged "Slide"), optional air control, optional anti-bunny hopping control, and special patented* Anti-Bump™ code that eliminates that irritating "bumpity bumpity bumpa bump" you get when trying to walk down moderately inclined slopes when using the default script.

*It's not really patented...it's just a small change actually.


In any situation where you'd normally use the standard FPSWalker script, you can replace it with this instead. The original parameters are still there and work as usual (although "speed" is now "walk speed").

  • Walk Speed: How fast the player moves when walking (the default).
  • Run Speed: How fast the player moves when running.
  • Limit Diagonal Speed: If checked, strafing combined with moving forward or backward can't exceed the normal movement rate. The horizontal and vertical movement axes are computed independently, so if this isn't checked, then diagonal speed is about 1.4 times faster than normal.
  • Toggle Run: If checked, the player can toggle between running and walking by pressing the run button (there must be a button set up in the Input Manager called "Run"). If not checked, the player normally walks unless holding down the run button.
  • Jump Speed: How high the player jumps when hitting the jump button (there must be a button set up in the Input Manager called "Jump", which there is by default).
  • Gravity: How fast the player falls when not standing on anything.
  • Falling Damage Threshold: How many units the player can fall before taking damage when landing. The script as-is merely prints the total number of units that the player fell if this happens, but the FallingDamageAlert function can be changed to do anything the programmer desires. The "fallDistance" local variable in this function contains the number of vertical units between the initial point of "catching air" and the final impact point. If falling damage is irrelevant, change the number to "Infinity" in the inspector, and the function will never be called.
  • Slide When Over Slope Limit: If checked, the player will slide down slopes that are greater than the Slope Limit as defined by the Character Controller. Attempting to jump up such slopes will also fail. The player has no control until resting on a surface that is under the Slope Limit.
  • Slide On Tagged Objects: If checked, the player will slide down any objects tagged "Slide" when standing on them, regardless of how much or little they are sloped. (The tag "Slide" must be added to the Tag Manager.) This can be used to create chutes, icy surfaces, etc. Note that tagged objects with zero slope will cause sliding in an undefined direction.
  • Slide Speed: How fast the player slides when on slopes as defined above.
  • Air Control: If checked, the player will be able to control movement while in the air, except when Slide When Over Slope Limit/Slide On Tagged Objects is enabled and the player is jumping off a slope over the limit (otherwise the player would be able to jump up supposedly inaccessible slopes).
  • Anti Bump Factor: An amount used to reduce or eliminate the "bumping" that can occur when walking down slopes, which is a result of the player constantly toggling between walking and falling small distances. The default of .75 is sufficient for most cases, although a little bit can still occur on steep slopes, assuming sliding isn't enabled. Larger amounts will stop this from ever happening, but too much can result in excessive falling speeds when stepping over an edge. Very small amounts will enable bumping, if that's desired for some reason.
  • Anti Bunny Hop Factor: Bunny hopping is repeated jumping by virtue of continuously holding down the jump button. Often considered annoying and silly, especially in multiplayer games. If the anti-hop value is at least 1, the player must release the jump button (and the release-and-hold-in-the-air trick is ineffective), and be grounded for the specified number of physics frames before being able to jump again. If the value is 0, then bunny hopping is allowed. If using noticeably large values, implementing some kind of visual indicator of jump availability is recommended to avoid player frustration.

The slope sliding is quite basic: the player is either sliding or not, and has no lateral control when sliding. One issue that may surface is that, under some circumstances, attempting to force oneself up a slippery slope will result in annoying jittering, as the character controller moves forward a bit one frame only to slide back the next frame, then moves forward a bit again, etc. Possible solutions are: add code to the script so this doesn't happen, design levels so as to minimize this, or ignore it and repeat to yourself "If it's good enough for UT2004, it's good enough for me." It's also not a good idea to create situations where the player slides into a V-shaped wedge valley where both slopes are unscalable, since the player will be stuck at the bottom, jittering for eternity. Not fun.

JavaScript - FPSWalkerEnhanced.js

<javascript>var walkSpeed = 6.0; var runSpeed = 11.0;

// If true, diagonal speed (when strafing + moving forward or back) can't exceed normal move speed; otherwise it's about 1.4 times faster var limitDiagonalSpeed = true;

// If checked, the run key toggles between running and walking. Otherwise player runs if the key is held down and walks otherwise // There must be a button set up in the Input Manager called "Run" var toggleRun = false;

var jumpSpeed = 8.0; var gravity = 20.0;

// Units that player can fall before a falling damage function is run. To disable, type "infinity" in the inspector var fallingDamageThreshold = 10.0;

// If the player ends up on a slope which is at least the Slope Limit as set on the character controller, then he will slide down var slideWhenOverSlopeLimit = false;

// If checked and the player is on an object tagged "Slide", he will slide down it regardless of the slope limit var slideOnTaggedObjects = false;

var slideSpeed = 12.0;

// If checked, then the player can change direction while in the air var airControl = false;

// Small amounts of this results in bumping when walking down slopes, but large amounts results in falling too fast var antiBumpFactor = .75;

// Player must be grounded for at least this many physics frames before being able to jump again; set to 0 to allow bunny hopping var antiBunnyHopFactor = 1;

private var moveDirection = Vector3.zero; private var grounded = false; private var controller : CharacterController; private var myTransform : Transform; private var speed : float; private var hit : RaycastHit; private var fallStartLevel : float; private var falling = false; private var slideLimit : float; private var rayDistance : float; private var contactPoint : Vector3; private var playerControl = false; private var jumpTimer : int;

function Start () { controller = GetComponent(CharacterController); myTransform = transform; speed = walkSpeed; rayDistance = controller.height * .5 + controller.radius; slideLimit = controller.slopeLimit - .1; jumpTimer = antiBunnyHopFactor; oldPos = transform.position; }

function FixedUpdate() { var inputX = Input.GetAxis("Horizontal"); var inputY = Input.GetAxis("Vertical"); // If both horizontal and vertical are used simultaneously, limit speed (if allowed), so the total doesn't exceed normal move speed var inputModifyFactor = (inputX != 0.0 && inputY != 0.0 && limitDiagonalSpeed)? .7071 : 1.0;

if (grounded) { var sliding = false; // See if surface immediately below should be slid down. We use this normally rather than a ControllerColliderHit point, // because that interferes with step climbing amongst other annoyances if (Physics.Raycast(myTransform.position, -Vector3.up, hit, rayDistance)) { if (Vector3.Angle(hit.normal, Vector3.up) > slideLimit) sliding = true; } // However, just raycasting straight down from the center can fail when on steep slopes // So if the above raycast didn't catch anything, raycast down from the stored ControllerColliderHit point instead else { Physics.Raycast(contactPoint + Vector3.up, -Vector3.up, hit); if (Vector3.Angle(hit.normal, Vector3.up) > slideLimit) sliding = true; }

// If we were falling, and we fell a vertical distance greater than the threshold, run a falling damage routine if (falling) { falling = false; if (myTransform.position.y < fallStartLevel - fallingDamageThreshold) FallingDamageAlert (fallStartLevel - myTransform.position.y); }

// If running isn't on a toggle, then use the appropriate speed depending on whether the run button is down if (!toggleRun) speed = Input.GetButton("Run")? runSpeed : walkSpeed;

// If sliding (and it's allowed), or if we're on an object tagged "Slide", get a vector pointing down the slope we're on if ( (sliding && slideWhenOverSlopeLimit) || (slideOnTaggedObjects && hit.collider.tag == "Slide") ) { var hitNormal = hit.normal; moveDirection = Vector3(hitNormal.x, -hitNormal.y, hitNormal.z); Vector3.OrthoNormalize (hitNormal, moveDirection); moveDirection *= slideSpeed; playerControl = false; } // Otherwise recalculate moveDirection directly from axes, adding a bit of -y to avoid bumping down inclines else { moveDirection = Vector3(inputX * inputModifyFactor, -antiBumpFactor, inputY * inputModifyFactor); moveDirection = myTransform.TransformDirection(moveDirection) * speed; playerControl = true; }

// Jump! But only if the jump button has been released and player has been grounded for a given number of frames if (!Input.GetButton("Jump")) jumpTimer++; else if (jumpTimer >= antiBunnyHopFactor) { moveDirection.y = jumpSpeed; jumpTimer = 0; } } else { // If we stepped over a cliff or something, set the height at which we started falling if (!falling) { falling = true; fallStartLevel = myTransform.position.y; }

// If air control is allowed, check movement but don't touch the y component if (airControl && playerControl) { moveDirection.x = inputX * speed * inputModifyFactor; moveDirection.z = inputY * speed * inputModifyFactor; moveDirection = myTransform.TransformDirection(moveDirection); } }

// Apply gravity moveDirection.y -= gravity * Time.deltaTime;

// Move the controller, and set grounded true or false depending on whether we're standing on something grounded = (controller.Move(moveDirection * Time.deltaTime) & CollisionFlags.Below) != 0; }

function Update () { // If the run button is set to toggle, then switch between walk/run speed. (We use Update for this... // FixedUpdate is a poor place to use GetButtonDown, since it doesn't necessarily run every frame and can miss the event) if (toggleRun && grounded && Input.GetButtonDown("Run")) speed = (speed == walkSpeed? runSpeed : walkSpeed); }

// Store point that we're in contact with for use in FixedUpdate if needed function OnControllerColliderHit (hit : ControllerColliderHit) { contactPoint = hit.point; }

// If falling damage occured, this is the place to do something about it. You can make the player // have hitpoints and remove some of them based on the distance fallen, add sound effects, etc. function FallingDamageAlert (fallDistance : float) { Debug.Log ("Ouch! Fell " + fallDistance + " units!"); }

@script RequireComponent(CharacterController) </javascript>

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