I am a beginner to Ebiten

[DAT4]

Hi, I am a beginner to Ebiten and game development in general. And I have a lot of questions!

I found your cheet sheet and it is really awesome, and really helpful. It got me started very fast.

I made a simple game now using go-websocket for multiplaying, by sharing commands in text.
I don't know if that is a good practice, but so far it is working and without any noticeable delay.

I don't know if GEO.Translate is the best function to use for the movement because there is a chance that the players actual coordinates will be wrong if some messages are lost ex. if the player disconnects and connects again then the other players will be in another unknown position.
Would it be better just to send the actual coordinates of the player over the websocket, and use them and in that case. Is there a function I can use to put the player in that spot instead of translating all the time?

Also I had some problems when I was trying to compile to wasm. Most of the time I got errors in the browser, and then when I got it to work then it didn't register me pressing the buttons for movement.

Most of all I was wondering if there is a way to present text and to get userinput in a nice way.
For example I would like to let the user login with his own username and password before he can start the game.
Also there is some choices he has to make to be able to start the game. So for example pressing a button which character he wants to be.
What would be the best way to implement interaction like this (userinput and menus/buttons)?

My game is here:
https://github.com/DAT4/go-game

[hajimehoshi]

Hi, thank you for using Ebiten!

Would it be better just to send the actual coordinates of the player over the websocket, and use them and in that case. Is there a function I can use to put the player in that spot instead of translating all the time?

This sounds like a general game system design question, rather than a question about Ebiten. I don't have a good answer but I'd make the server have the master data and each client render them as the easiest way.

Also I had some problems when I was trying to compile to wasm. Most of the time I got errors in the browser, and then when I got it to work then it didn't register me pressing the buttons for movement.

What kind of error did you get?

Most of all I was wondering if there is a way to present text and to get userinput in a nice way.

What about ebiten.InputChars?

[DAT4]

Right now I am doing the same as in the filter example Where a new instance of DrawImageOptions{} are created in the Draw function. It works, and I don't feel anything slowing down but I think it would be possible to optimize if I could just have one instance of the struct and then modify the numbers.

Maybe I am wrong :)

[AWachtendorf]

Okay, to most of the examples create some objects that are then called globally in the Draw and Update functions. Whihc is fine. But if you want to include more structs to work with I usually go the way you see below. I hope you can read it, as I cant get the bloody syntax highlighting to work. (Any tip for that? Might just be something I do wrong in github... )

// Ship could be a spaceship.
type Ship struct {
shipimg *ebiten.Image
shipImageOptions *ebiten.DrawImageOptions
posX, posY float64
}

// DrawShipOnScreen is for translating our Ship Image.
func (s *Ship) DrawShipOnScreen(screen *ebiten.Image) {
s.shipImageOptions.GeoM.Reset() // reset matrix so it does not get updated in endless loop
s.shipImageOptions.GeoM.Translate(-s.width/2, -s.height/2) // translate at center of image
s.shipImageOptions.GeoM.Translate(s.posX, s.posY) //image is always translated to those koordinates
screen.DrawImage(s.shipImg, s.shipImageOptions) // Draw the image
}

// Update listens to pressed keys and changes the posX,posY values.
// As those are pointed to the *Ship struct our drawn image is moved
func (s *Ship) Update() error {
if ebiten.IsKeyPressed(ebiten.KeyW) {
s.posY -= 0.5
}

if ebiten.IsKeyPressed(ebiten.KeyS) {
	s.posY += 0.5
}

}

// The Game struct can then include a *Ship
type Game struct {
ship *Ship
}

// Update is called constantly, this is the place where I let
// the game listen to changes
func (g *Game) Update() error {
g.ship.Update()
}

// Draw now calls the Draw function in our ship
func (g *Game) Draw(screen *ebiten.Image) {
g.ship.DrawShipOnScreen(screen)
}

[hajimehoshi]

Just a quick reply:

You mentioned that I should just use GeoM.Apply()

Oops sorry, I misread that. You should use GeoM.Translate

[hajimehoshi]

So I think you want to put an image on an absolute position, right? I think you are trying to reuse DrawImageOptions objects, but in this case you don't have to. You can create DrawImageOptions on the fly. Even if you want to reuse them for performance reasons, you can call GeoM.Reset() so that all values become 0.

[DAT4]

Thank you. :)