Can't create sprite? - GameCreators Forum

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Ched80

14

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Joined: 18th Sep 2010

Location: Peterborough, UK

Posted: 31st Jan 2014 18:17

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OK I admit defeat.

I'm running the CreateAllAsteroids function (see below), but AppGameKit seems to get stuck at some point creating one of the new sprites.

What's weird is that it will crash at random points. The function attempts to create 24 sprites from the same image, but sometimes it will crash on the first sprite, sometimes on the 18th, sometimes on the 6th.

I'm really lost with this one so any help will be great.

I'm running v108.19 on win7.

The functions are below.

function CreateAllAsteroids()
//creates all asteroid objects

for a=0 to MaxAsteroids

CreateNewAsteroid(a,0)

next a

endfunction

function CreateNewAsteroid(AsteroidID as integer, KnownMass as float)
//creates a new asteroid object

a = AsteroidID

//delete old sprite if exists
    spriteid = asteroid[a].spriteid
    if getspriteexists(spriteid)=1 then deletesprite(spriteid)

//CREATE SPRITE
    //pick an asteroid image
    ImageID = AsteroidImg

repeat
        spriteid = createsprite(ImageID)
        asteroid[a].spriteid = spriteid

if getspriteexists(asteroid[a].spriteid)=0
            deletesprite(spriteid)
            print("lost sprite "+str(spriteid))

endif
    until getspriteexists(asteroid[a].spriteid)=1

if DevMode=1
        print("Astroid "+str(a)+" sprite created.")
    endif

fixspritetoscreen(spriteid,0)
    rscale# = random(200,600) * 0.01
    setspritescale(spriteid,rscale#,rscale#)
    setspriteoffset(spriteid,getspritewidth(spriteid)/2,getspriteheight(spriteid)/2)
    setspritedepth(spriteid,5000)

PositionOK = 1

posangle# = 1.0 * random(0,360)
    Radius# = AstSpawnDist * random(100,200) * 0.01
    xpos# = getspritexbyoffset(PlrDroid[0].spriteid) + (Radius# * sin(posangle#))
    ypos# = getspriteybyoffset(PlrDroid[0].spriteid) + (Radius# * cos(posangle#))

if DevMode=1
        print("Astroid "+str(a)+" PosAngle:"+str(posangle#,1)+", X:"+str(xpos#,1)+", Y:"+str(ypos#,1))
    endif

setspritepositionbyoffset(spriteid,xpos#,ypos#)

posangle# = 1.0 * random(0,360)
    setspriteangle(spriteid,posangle#)

setspriteshape(spriteid,3)
    setspritephysicson(spriteid,2)

if DevMode=1
        print("Astroid "+str(a)+" Physics ON")
    endif

//set initial velocity
    posangle# = 1.0 * random(0,360)
    vmax# = 1.0 * random(0,20)
    vx# = (vmax# * sin(posangle#))
    vy# = (vmax# * cos(posangle#))
    setspritephysicsvelocity(spriteid,vx#,vy#)

if DevMode=1
        print("Astroid "+str(a)+" Velocity Set to "+str(vx#,1)+","+str(vy#,1))
    endif

setspritevisible(spriteid,1)

//ASTEROID STATS
    asteroid[a].life = random(20000,40000)

if KnownMass>0
        asteroid[a].mass = KnownMass
    else
        //random mass
        asteroid[a].mass = random(5000,105000)*0.001
    endif

SetAsteroidElements(a)

if DevMode=1
        print("Astroid "+str(a)+" elements set.")
        sync()
    endif

endfunction

+ Code Snippet

function CreateAllAsteroids()
//creates all asteroid objects

    for a=0 to MaxAsteroids

        CreateNewAsteroid(a,0)

    next a

endfunction





function CreateNewAsteroid(AsteroidID as integer, KnownMass as float)
//creates a new asteroid object

    a = AsteroidID

    //delete old sprite if exists
    spriteid = asteroid[a].spriteid
    if getspriteexists(spriteid)=1 then deletesprite(spriteid)

    //CREATE SPRITE
    //pick an asteroid image
    ImageID = AsteroidImg

    repeat
        spriteid = createsprite(ImageID)
        asteroid[a].spriteid = spriteid

        if getspriteexists(asteroid[a].spriteid)=0
            deletesprite(spriteid)
            print("lost sprite "+str(spriteid))

        endif
    until getspriteexists(asteroid[a].spriteid)=1

    if DevMode=1
        print("Astroid "+str(a)+" sprite created.")
    endif

    fixspritetoscreen(spriteid,0)
    rscale# = random(200,600) * 0.01
    setspritescale(spriteid,rscale#,rscale#)
    setspriteoffset(spriteid,getspritewidth(spriteid)/2,getspriteheight(spriteid)/2)
    setspritedepth(spriteid,5000)

    PositionOK = 1

    posangle# = 1.0 * random(0,360)
    Radius# = AstSpawnDist * random(100,200) * 0.01
    xpos# = getspritexbyoffset(PlrDroid[0].spriteid) + (Radius# * sin(posangle#))
    ypos# = getspriteybyoffset(PlrDroid[0].spriteid) + (Radius# * cos(posangle#))

    if DevMode=1
        print("Astroid "+str(a)+" PosAngle:"+str(posangle#,1)+", X:"+str(xpos#,1)+", Y:"+str(ypos#,1))
    endif

    setspritepositionbyoffset(spriteid,xpos#,ypos#)

    posangle# = 1.0 * random(0,360)
    setspriteangle(spriteid,posangle#)

    setspriteshape(spriteid,3)
    setspritephysicson(spriteid,2)

    if DevMode=1
        print("Astroid "+str(a)+" Physics ON")
    endif

    //set initial velocity
    posangle# = 1.0 * random(0,360)
    vmax# = 1.0 * random(0,20)
    vx# = (vmax# * sin(posangle#))
    vy# = (vmax# * cos(posangle#))
    setspritephysicsvelocity(spriteid,vx#,vy#)

    if DevMode=1
        print("Astroid "+str(a)+" Velocity Set to "+str(vx#,1)+","+str(vy#,1))
    endif

    setspritevisible(spriteid,1)

    //ASTEROID STATS
    asteroid[a].life = random(20000,40000)

    if KnownMass>0
        asteroid[a].mass = KnownMass
    else
        //random mass
        asteroid[a].mass = random(5000,105000)*0.001
    endif

    SetAsteroidElements(a)

    if DevMode=1
        print("Astroid "+str(a)+" elements set.")
        sync()
    endif

endfunction

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TrezSoft

AGK Tool Maker

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Joined: 8th Nov 2012

Location: UK

Posted: 31st Jan 2014 19:02

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Maybe this line fixspritetoscreen(spriteid,0)

As you should not use physics or collisions with fixed sprites.

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Ched80

14

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Joined: 18th Sep 2010

Location: Peterborough, UK

Posted: 31st Jan 2014 19:18

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Cheers TrezSoft, but the "0" in that command is not fixing the sprite.

Anyway I'm desperate so I tried commenting the command out, but it made no difference.

Incidentally the error code I get is 805306369 which seems to suggest there is a memory leak somewhere.

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TrezSoft

AGK Tool Maker

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Joined: 8th Nov 2012

Location: UK

Posted: 31st Jan 2014 19:35

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Missed that sorry , why bother fixing it at all then ?

anyway whats going on here:

spriteid = createsprite(ImageID)
asteroid[a].spriteid = spriteid

if getspriteexists(asteroid[a].spriteid)=0
deletesprite(spriteid)
print("lost sprite "+str(spriteid))

endif
until getspriteexists(asteroid[a].spriteid)=1

maybe i am missing something but why create it check if it does not exist and then try and delete it ?

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Ched80

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Joined: 18th Sep 2010

Location: Peterborough, UK

Posted: 31st Jan 2014 20:04

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Ah that weird double check is to catch another weird bug. I found that this line:

asteroid[a].spriteid = spriteid

wouldn't always work and later in the game i would end up with the screen filled with hundreds of sprites.

So to stop that, i just check that the sprite ID has been copied correctly - if it hasn't it deletes the sprite and tries again.

Anyhooo, i just spotted 108.21 and having installed this - the bug has vanished

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Ancient Lady

Valued Member

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Joined: 17th Mar 2004

Location: Anchorage, Alaska, USA

Posted: 1st Feb 2014 03:09

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This might not be all of it, but try changing this:

+ Code Snippet

    spriteid = asteroid[a].spriteid
    if getspriteexists(spriteid)=1 then deletesprite(spriteid)
    //CREATE SPRITE
    //pick an asteroid image
    ImageID = AsteroidImg

    repeat
        spriteid = createsprite(ImageID)
        asteroid[a].spriteid = spriteid

        if getspriteexists(asteroid[a].spriteid)=0
            deletesprite(spriteid)
            print("lost sprite "+str(spriteid))

        endif
    until getspriteexists(asteroid[a].spriteid)=1

to this:

+ Code Snippet

    spriteid = asteroid[a].spriteid
    if getspriteexists(spriteid)=1 then deletesprite(spriteid)

    // make sure that the id is zero for next step
    asteroid[a].spriteid = 0

    //CREATE SPRITE
    //pick an asteroid image
    ImageID = AsteroidImg

    repeat
        // create the sprite
        spriteid = createsprite(ImageID)

        // don't store the id until it is a good one
        if getspriteexists(spriteid)=0
           // don't need to delete the sprite because it
           // doesn't exist and trying to delete a non-zero
           // id might cause a crash
           print("lost sprite "+str(spriteid))

           // we know that the sprite doesn't exist
           // go back to top
           continue;
        endif
    until getspriteexists(spriteid)=1

    // don't store the id until it is a good one
    asteroid[a].spriteid = spriteid

And, you should consider changing that first repeat loop so that it stops after <x> iterations and declare a program failure. If there is something fundamentally breaking when you try to create a sprite and you keep trying, it could get stuck in a loop or memory crash.

Cheers,
Ancient Lady
AGK Community Tester and AppGameKit Master

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Phaelax

DBPro Master

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Joined: 16th Apr 2003

Location: Metropia

Posted: 1st Feb 2014 08:45

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I'm trying to figure out what the point of this code here is:

+ Code Snippet

    repeat
        spriteid = createsprite(ImageID)
        asteroid[a].spriteid = spriteid

        if getspriteexists(asteroid[a].spriteid)=0
            deletesprite(spriteid)
            print("lost sprite "+str(spriteid))

        endif
    until getspriteexists(asteroid[a].spriteid)=1

You create a sprite, then if it doesn't exist you'll delete it. That makes absolutely no sense.

http://zimnox.com

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Marl

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Joined: 19th Nov 2011

Location: Bradford, UK

Posted: 1st Feb 2014 16:04

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Wouldn't it be simpler to re-use the sprite if it exists ?

+ Code Snippet

spriteid = asteroid[a].spriteid
if getspriteexists(spriteid) = 0
   spriteid = createsprite(ImageID)
   asteroid[a].spriteid = spriteid
else
   setspriteimage( spriteid , ImageID )
endif
...

More efficient then deleting and recreating sprites

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Ched80

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Joined: 18th Sep 2010

Location: Peterborough, UK

Posted: 1st Feb 2014 23:56

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Cheers for the help guys. I'll try and add a bit more context.

When the game starts it creates all 24 asteroids in one go.

As the game is ran it checks to see if any sprites have wandered too far from the player or if the sprite no longer exists and it re-runs the CreateAsteroid functions for a specific ID.

The reason for creating a sprite and then checking to see if the ID was copied across to the array correctly - I'm pretty sure the sprite is created corrected, but for some reason AppGameKit doesn't copy to ID into the array correctly all the time.

So unless I put that weird check in, I end up with hundreds of sprites filling the screen.

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