shaking image when using a normalized direction

[DWethmar]

Hey,

Maybe a stupid question but when i try to normalize a x, y position its seems that the image that i try to draw shakes in the diagonal directions..

import (
	"fmt"
	"image/color"
	"math"

	"github.com/hajimehoshi/ebiten/v2"
	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
)

var (
	screenWidth  = 320
	screenHeight = 240
)

type Game struct {
	X, Y float64
}

func (g *Game) Update() error {
	var x float64
	var y float64

	if ebiten.IsKeyPressed(ebiten.KeyA) {
		x = x - 1
	}

	if ebiten.IsKeyPressed(ebiten.KeyD) {
		x = x + 1
	}

	if ebiten.IsKeyPressed(ebiten.KeyW) {
		y = y - 1
	}

	if ebiten.IsKeyPressed(ebiten.KeyS) {
		y = y + 1
	}

	// normalize
	if length := math.Sqrt(x*x + y*y); length > 0 {
		x = x / length
		y = y / length
	}

	g.X = g.X + x
	g.Y = g.Y + y

	return nil
}

func (g *Game) Draw(screen *ebiten.Image) {
	ebitenutil.DebugPrint(screen, fmt.Sprintf("X: %0.2f, Y: %0.2f", g.X, g.Y))

	ebitenutil.DrawRect(screen, g.X, g.Y, 10, 10, color.White)
}

func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
	return screenWidth, screenHeight
}

func main() {
	ebiten.RunGame(&Game{})
}

Is there a way to make the movement smooth?

Thanks!

[hajimehoshi]

How was the movement not smooth?

[DWethmar]

Wel maybe its just me but when i input W & D its seems to stutter more then only pressing D.

If i remove the normalization then its smooth

I'm on a Mac M1

🤷🏼‍♂️

[hajimehoshi]

OK so DrawRect is not suitable for this purpose.

Rendering a rectangle with FilterLinear should solve your issue.