Move 3d object in direction it faces

poof92

So I've set up a little game where you have a basic player and I can rotate it with c.lx but when I push up with c.ly then it goes in a fixed direction I've even used the 3d tutorials but to no avail

PickleCatStars

sin() and cos() are probably what you want to use here. Fuze even has a sincos() function that’ll do them both at once.

Assuming a fixed camera, and if I’m remembering correctly, If you do something like

Player.x += sin(player.angle)*c.ly
Player.z += cos(player.angle)*c.ly

That should at least give you an idea to get you started...

Dave

The above is correct - but we can make something useful here which is referred to as a forward vector. This is a calculated direction vector which takes the sin() and cos() of the player angle into account - and it can be used to get other useful vectors as well, such as the 'side' vector - which describes the direction to the left and right of the forward (think holding your arms out in a T shape).

For this I'll assume you have a vector to describe the player position as opposed to separate x, y and z variables.

// You might also want something to adjust the angle the player is facing, for example the right stick X axis:
playerAngle += c.rx

playerForward = {cos(playerAngle), 0, sin(playerAngle)} // 0 on the Y axis assuming you don't want to fly around but move on the ground.
playerPos += playerFoward * c.ly // Add the player forward vector to player position, using the controller Y axis value as a modifier.

You will likely need to modify the controller variables (.ly/.rx etc) to make the numbers move nicely in your project, depending on the scale of things and such. Usually multiplying them by zero point something is a good place to start.

To get the side vector, we can take the cross product of the player forward vector and the pure Y axis. This would give us left and right movement, mapped to something like the left stick X axis this creates complete movement!

playerSide = cross(playerForward, {0, 1, 0})
playerPos += playerSide * c.lx

Apologies if it's more info than needed, but just wanted to make sure you had this to refer to if you require it!

PickleCatStars

You could use that side vector to shoot missiles out of the side of your car.

Dave

@toxibunny I second, third and fourth this idea! What a perfect application!

poof92

Awesome thanks so much I'll give it a try

poof92

It works for the most part but the object doesn't move towards its face.

PickleCatStars

If it’s off by 90 degrees or whatever, you can always just bodge it.

playerForward = {cos(playerAngle +90 ), 0, sin(playerAngle +90 )}

For example.

poof92

Awesome it works perfectly now thanks