Image Glitch When Window Loses Focus

[temidaradev]

Ebitengine Version

v2.8.4

Operating System

• Windows
• macOS
• Linux
• FreeBSD
• OpenBSD
• Android
• iOS
• Nintendo Switch
• PlayStation 5
• Xbox
• Web Browsers

Go Version (go version)

1.23.2

What steps will reproduce the problem?

Implementing assets by using esset library: var GopherIdle = esset.GetAsset(assets, "gopher/mainchar.png")

Drawing background like this:

func MakeBackground(screen *ebiten.Image) {
	for i := 0; i < 100; i++ {
		for j := 0; j < 100; j++ {
			dio := &ebiten.DrawImageOptions{}
			dio.GeoM.Translate(1800-float64(i*50), 1700-float64(j*50))
			cam.Draw(assets.Tiles[1], dio, screen)
		}
	}
}

and also I used kamera library https://github.com/setanarut/kamera and here is the code of movement:

func Axis() (axisX, axisY float64) {
	if ebiten.IsKeyPressed(ebiten.KeyW) {
		axisY -= 1
	}
	if ebiten.IsKeyPressed(ebiten.KeyS) {
		axisY += 1
	}
	if ebiten.IsKeyPressed(ebiten.KeyA) {
		axisX -= 1
	}
	if ebiten.IsKeyPressed(ebiten.KeyD) {
		axisX += 1
	}
	return axisX, axisY
}

and here is the cam.LookAt usage

        var low float64 = 0
        var high float64 = 1500

        camPosX := Clamp(g.player.X, low, high)
	camPosY := Clamp(g.player.Y, low, high)

	cam.LookAt(camPosX, camPosY)

and here is player's Update() func

func (p *Player) Update() error {
	x, y := Axis()

	p.X += x * p.speed
	p.Y += y * p.speed

	p.DIO.GeoM.Reset()

	p.DIO.GeoM.Translate(
		p.X-float64(assets.GopherIdle.Bounds().Dx()/2),
		p.Y-float64(assets.GopherIdle.Bounds().Dy()/2),
	)

	//p.X = min(max(p.X, -230), 1740)
	//p.Y = min(max(p.Y, -120), 1610)

	p.X = Clamp(p.X, -230, 1740)
	p.Y = Clamp(p.Y, -120, 1610)

	return nil
}

and here is the Draw() func

func (g *Game) Draw(screen *ebiten.Image) {
	MakeBackground(screen)
	g.player.Draw(screen)
}

What is the expected result?

Stable and normal behavior of gopher.

What happens instead?

Glitchy and scary gopher

Screen.Recording.2024-11-21.at.21.04.28.mov

Anything else you feel useful to add?

No response

[hajimehoshi]

Please provide the entire (minimized) project to reproduce the issue

[temidaradev]

https://github.com/temidaradev/RpiZeroWEbiten.git here is the repo

[hajimehoshi]

Could you minimize the source code to reproduce this issue?

[temidaradev]

Could you minimize the source code to reproduce this issue?

OK, I tried to minimize it by putting important codes

[hajimehoshi]

OK, I tried to minimize it by putting important codes

Unfortunately this is not enough. Your code depends on libraries like github.com/setanarut/kamera/v2 and there might be an issue there. Please minimize it or ask the author of the library.

EDIT: Does this issue happen without the kamera library?

[temidaradev]

ah wait let me test it

[temidaradev]

ah yes when I tried to use screen.DrawImage(assets.GopherIdle, p.DIO) instead of cam.Draw(assets.GopherIdle, p.DIO, screen) my gopher doesn't do any flicker or glitches

[hajimehoshi]

So there might be an issue there. Ask the author.

[setanarut]

This is caused by faulty code. Draw and GeoM are incorrectly drawn twice. This is not caused by the Kamera package. (code of @temidaradev)