Player Movement Fixes

A very large portion of the time you spend in this class will be researching bugs like the ones we have with out movement. For this tutorial, we will show you how to fix some of these bugs.

Constraining the Rigidbody

The most noticable problem is the spinning. We could try to force the character upright through scripting, but it’s easier to do so through the Player’s Rigidbody component.

Under Constraints, freeze the rotation on every axis.

While we’re here, also freeze the position the z-axis so the character doesn’t move back in space. You should do this with all of your Rigidbodys for this project.

Constraints

Input Manager Fixes

You may have noticed the player gradually speeds up instead of starting with full velocity. This is because by default Unity tries to mimic joystick controls for Input.GetAxis, trying to smooth out changes between the keys.

o to Edit->Project Settings->Input and set the gravity to inf and set the sensitivity to inf.

Inf

Physic Materials

You may have noticed the player sticks to walls if you hold the direction into them. This is because there is a lot of friction from the horizontal force keeping Samus up vertically.

Friction is sometimes a good thing, but in Metroid we have no need for it.

Create a new folder in your Assets named PhysicMaterials. Inside of it right click anywhere and do Create->Physic Material. Name it Frictionless

FrictionlessAsset

Now set the Dynamic Friction and Static Friction to 0.

Frictionless

Set this as the Material for the Capsule Collider of Standing (the child of Player).

FrictionlessApplied

Also set this as the Material for the Box Collider of the Tile_WALL prefab.

FrictionlessApplied2

So why are we using a Capsule Collider for the player anyway? (Important!)

It would seem like a box collider would make more sense here. However, the collision in Unity is unfortunately not ideal for Tile based games.

Essentially how the collision works is that each physics update, the rigidbody object moves its velocity. Then it is pushed out of anything it moved into. Unfortunately, it may get pushed out of the sides of a tile before it gets pushed out of the top/bottom of another tile. This could cause the player to stop and get stuck, but having a round bottom "fixes" this.

Unfortunately this isn't the only problem Unity's physics causes. You may notice the player bounce slightly, and even still get stuck on walls at intersections between tiles. This is one of the problems you'll need to figure out while polishing this project

You're two most likely options are to either:

A: Check if the player is going to run into a wall and stop the velocity in that direction if they are (you can do this through Box Casts).

B: Implement your own predictive movement, moving your character up to the velocity in both axises but stopping if it's going to hit an object.

This isn't something you should concern yourself over too much right now, but if you need more help in the future be sure to come talk to us during office hours.

Checking Grounded

The last thing you may have noticed is that the player can still jump while airborne. Let’s check to see if the player is grounded before we let them jump.

Create a new function IsGrounded() that returns a bool. In it, SphereCast from the child’s collider’s center down to just below the bottom of the collider.

IsGrounded

What is a SphereCast?

SphereCasts, like RayCasts, allow you to check if there's anything in the way along a path. They are most common in First Person Shooters where you'll want bullets to travel instantly.

Now just add the IsGrounded() check before you jump.

IsGrounded

If I'm just checking for a collider, doesn't that mean I might be able to jump of other colliders like enemies heads?

Yep! This is something you'll probably want to fix at some point. Hint: Use LayerMasks

Jump Strength

Now that we’re able to actually play our game, you may have noticed that we went a little overkill with our initial jump strength. You can just go ahead and dial this down to 12 in the editor, no need to change your script!

DownTo12

Conclusion

Fixed

This was only the basics of movement and you’ll find in your analysis that there’s a bit more to Metroid than just this (running jumps, jumps dependent on how long you hold the button, etc…). However that’s all the time we’re going to spend on it here.

When you’re ready, commit and go to the next tutorial: 08-Player Direction.