Add inertia to Pawn movement

Development Programming & Scripting C++
1

I’ve just started to learn Unreal Engine 4.26.2 while developing an Atari’s Pong clone.

To move the Paddle I’m using this code:

// Called to bind functionality to input
void APaddle::SetupPlayerInputComponent(UInputComponent* PlayerInputComponent)
{
	Super::SetupPlayerInputComponent(PlayerInputComponent);

	// Respond every frame to the values of our movement.
	InputComponent->BindAxis(TEXT("MovePaddle"), this, &APaddle::Move_ZAxis);
}

void APaddle::Move_ZAxis(float AxisValue)
{
	CurrentVelocity.Z = FMath::Clamp(AxisValue, -1.0f, 1.0f) * 100.0f;
}

But I want to do two things:

  1. While the user is pressing the key the paddle movement will accelerate.

  2. When the user release the key the Paddle won’t stop immediately; instead, it will slowing down until it stops.

Is there anything done with Physics that I can use here or do I have to implement it by myself?

By the way, I’m not English and I don’t know if inertia is the right word here.

2

I haven’t implemented custom movement in Unreal before, but I’ve spent a lot of time with these in Unity. Since the movement in Pong has to be responsive, I’d go with the following solution: You have your velocity, that’s good. Instead of setting the velocity directly, you set a target velocity, and interpolate (smoothly reach) the current v. to the target v. continuously.

// in input code
TargetVelocity.Z = FMath::Clamp(AxisValue, -1.0f, 1.0f) * 100.0f;

// in tick (so every frame)
// higher interp speed will result in more responsive movement
CurrentVelocity.Z = FMath::FInterpTo(CurrentVelocity.Z, TargetVelocity.Z, DeltaSeconds, InterpSpeed);
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3

Thanks for your answer but it can be achieved using Physics?

4

As in using forces? Of course, but there is no point really. IMO it’s better to control the velocity directly when dealing with character/player movement. But if you want to use forces no matter what, then use AddForce() and play around with the mass and linear damping values of the physics body.

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