Finding it hard to get enemies

Dave

Absolutely happy to. There is a way I could provide a very "simple" example, without using states etc, but in my opinion it honestly ends up being far more complicated.

Usually I begin with something like this:

spritesheet = loadImage("filename")
sprite = createSprite()
setSpriteImage( sprite, spritesheet )

// Now we create an array of animation data. Each element of this array is an array of two elements, the start tile and the end tile. 
// Numbers are of course arbitrary.
playerAnimationData = [
    [ 0, 6 ], // let's say this is the idle animation
    [ 7, 20 ], // this one could be an attack animation
    [ 21, 30 ] // this one could be jump
]

// Now we make state variables to use as indexes into that animation array:
idle = 0
attack = 1
jump = 2

// Now the variable to store the current state
state = idle

// We will also **need** to keep track of the player's **old state**, in order to tell when we change animation.
oldState = -1 // Making it -1 for now because we'll be setting it properly in the loop.

// Lastly, a flag variable make sure that we only trigger the ``setSpriteAnimation()``` once
animSwitch = false

Okay, with that done, we can have something like the following in our main loop:

loop
    clear()
    updateSprites()
    j = controls(0)

    // It's extremely useful to know which frame of animation you character is on, so let's make a local variable for that:    
    playerFrame = getSpriteAnimFrame( sprite )    

    // If A is pressed and the character was not previously in the jump state, enter jump state and set the animSwitch
    if j.a and oldState != jump then
        animSwitch = true
        state = jump
    endif

    // You might want your attack to only be possible if the player is not jumping, for instance:
    if j.x and oldState != attack and oldState != jump then
        animSwitch = true
        state = attack
    endif    

    // With the sprite's current animation frame known, we can also easily return to idle after certain animations:
    if state == attack and playerFrame >= playerAnimationData[state][1] then
        animSwitch = true
        state = idle
    endif

    // Notice that in our if statements, we simply need only change the state and turn the animation switch on. If we weren't using an array of animation data with a state machine,
    // we would have to do separate ```setSpriteAnimation()``` calls for each if statement. This ends up being quite cluttered and not so simple when you've got a large scale project.
    
    // However, with this way of doing things, we simply need this one if statement at the end. We check if the current state is != oldState and if our switch is on:
    if state != oldState and animSwitch then
        // playerAnimationData[ state ][0] contains the start tile for the current state, playerAnimationData[ state ][1] is the end tile
        setSpriteAnimation( sprite, playerAnimationData[ state ][0], playerAnimationData[ state ][1], 10 ) // 10 fps is arbitrary
        animSwitch = false // turn the switch off
    endif
    
    // Finally, we update the oldState variable to contain the current state at the end of the frame.
    oldState = state
    update()
repeat

I might be missing a couple of small details here as I didn't want to overload, but this is the method I'm using in the updated gothic Vania demo and it works nicely. It also grants you a lot of control over which states happen when.

Actually, looking at this I'm not sure you actually need the animSwitch variable, since just knowing if the state is not equal to the old state might be enough. I would use it for good measure!

I really hope this is what you were looking for. Please let me know if I can elaborate on anything at all.

lawyerlounge

Thanks again for a great example. I noticed there was no use of drawSprites() in your loop. Is that possibly the reason I had issues with the animation not running?

image = loadImage("filename")
sprite = createSprite()
setSpriteImage( sprite, image)

startFrame = 0
endFrame  = 10
fps = 10

Loop
      clear()
    
      setSpriteAnimation( sprite, startFrame, endFrame, fps)

      updateSprites()
      drawSprites()

      update()
repeat

I remember just trying to get the animation to work anywhere inside the loop (without any states or conditions) resulted in no movement at all. Is it because I was misusing some sort of update() command or drawSprites() command, and it kept redrawing the initial start frame and not allowing the animation to count up to 10 at 10 fps? I'm at work and away from my switch, but I believe I tried almost all combinations of including/excluding any update() draweSprites() and updateSprites() to no avail.

Does that make sense though?

pianofire

@lawyerlounge setSpriteAnimation() initializes the animation. If you call it in your game loop it will keep resetting it back to the beginning. The updateSprites() call is the one that will move the animation forward. drawSprites() will actually draw them into video memory and update() will render that to the screen.

So this should work (let me know if it doesn't). You also need to set the sprite location using setSpriteLocation

sprite = createSprite()
setSpriteImage( sprite, image)
setSpriteLocation(sprite, gwidth()/2, gheight()/2)
startFrame = 0
endFrame  = 10
fps = 10
setSpriteAnimation( sprite, startFrame, endFrame, fps)

Loop
      clear()
    

      updateSprites()
      drawSprites()

      update()
repeat

Jonboy

Ha Waldron... "Finding it hard to get enemies".. I make new ones every day!

Sorry.. can't be much more help than that at the moment. See what I mean.

lawyerlounge

What is the main difference from Dave's example (2 posts up) and my example (which both at some point have the setSpriteAnimation() function inside of the main loop) that would cause his to work and mine not to.

Other than having "if statements" (which basically change a variable called "state" which in turn changes the startFrame and endFrame vars for the arguments within setSpriteAnimation), and providing a check to see if the current state is not what it used to be, what causes the program in Dave's post to let the animation run from start to finish without constantly executing the beginning of the animation? (the problem you dissected within my example)

Or is the method of checking if state != oldState required, because if you intend an animation to change throughout the main loop you need to find a way to only run it once at particular moments? And for any asset that doesn't need to change animations you would just use the setSpriteAnimation function before the main loop and set the visibility to false until needing to display?

I think I've figured out the bare requirements for using sSA() in the loop... would this work?

sprite = createSprite()
setSpriteImage( sprite, image)
setSpriteLocation(sprite, gwidth()/2, gheight()/2)
startFrame = 0
endFrame  = 10
fps = 10

animSwitch = true

Loop
      clear()
     
      currentFrame = getSpriteAnimFrame( sprite )

      if animSwitch then
            setSpriteAnimation( sprite, startFrame, endFrame, fps)
            animSwitch = false
      endif

      if currentFrame >= endFrame then
            animSwitch = true
      endif

      updateSprites()
      drawSprites()

      update()
repeat

P.S. thank you for all of the help teaching me something that must be simple for you guys!
-MikeV

pianofire

@lawyerlounge Not at all. That's what we are here for. Yes you only want to call setSpriteAnimation to change the current animation. The set animation will be repeated until a new one is set. If you want more control over the animation you can use setSpriteAnimFrame but you will have to control the speed yourself:

https://fuzearena.com/help/view/setSpriteAnimFrame

lawyerlounge

Nice! so my example should display the animation on loop? (not at home yet to test it)

pianofire

@lawyerlounge Well I haven't tried it but yes it looks like it should

waldron

@Jonboy haha i must be to nice

Jonboy

ha, but not TOO nice. See, i did it again. Seriously, you should not invite me to comment :-)

Dave

@lawyerlounge My bad! Completely forgot about perhaps the most important command, drawSprites(), in the example I gave.