firework spinner effect - GameCreators Forum

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ICERGB

22

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Joined: 8th Nov 2002

Location: Canada

Posted: 23rd Nov 2012 11:15

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Is there an easy way to make a physics sprite act as if it was like a spinning firecracker?

So its angle would cycle through 0 to 360 and push like it had propulsion?

Or could someone at least tell me how it could be done?
Would I use SetSpritePhysicsImpulse?

Ive been trying to use SetSpritePhysicsImpulse but I don't think I am getting the force to push it properly...

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baxslash

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Joined: 26th Dec 2006

Location: Duffield

Posted: 23rd Nov 2012 12:52

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Yes, just apply an angular velocity and a linear velocity based on its current angle:

setVirtualResolution(640,480)

spr = createSprite(0)
setSpritePositionByOffset(spr,320,120)
setSpriteSize(spr,40,6)
setSpritePhysicsOn(spr,2)

type sparkType
    spr as integer
    die as float
endtype
dim spark[0] as sparkType
spark[0].spr = 0
global time as float

do
    time = timer()
    
    rem get sprite data
    sa# = getSpriteAngle(spr)
    sx# = getSpriteXbyOffset(spr)
    sy# = getSpriteYbyOffset(spr)
    
    rem apply angular impulse
    setSpritePhysicsAngularImpulse(spr,8)
    
    rem apply linear impulse
    vx# = cos(sa#)*40
    vy# = -sin(sa#)*40
    setSpritePhysicsImpulse(spr,sx#,sy#,vx#,vy#)
    
    rem sparks
    createSpark(sx#,sy#,-vx#,vy#)
    updateSparks()
    
    sync()
loop

function createSpark(x#,y#,vx#,vy#)
    spr = createSprite(0)
    setSpriteSize(spr,2,-1)
    setSpritePositionByOffset(spr,x#+vx#*0.5,y#+vy#*0.5)
    setSpritePhysicsOn(spr,2)
    setSpritePhysicsVelocity(spr,vx#*2,vy#*2)
    n = spark[0].spr + 1
    dim spark[n] as sparkType
    spark[0].spr = n
    spark[n].spr = spr
    spark[n].die = time + 2.0
endfunction

function updateSparks()
    n = spark[0].spr
    for i=1 to n
        die# = spark[i].die
        spr  = spark[i].spr
        if die#-time>0
            f# = (die#-time)*0.5
            if i=1 then print(str(f#))
            c# = f#*255.0
            setSpriteColor(spr,c#,255.0-c#,0,c#)
        else
            deleteSprite(spr)
            spark[i].spr = spark[n].spr
            spark[i].die = spark[n].die
            dec n
            dec i
            dim spark[n] as sparkType
            spark[0].spr = n
        endif
    next
endfunction

+ Code Snippet

setVirtualResolution(640,480)

spr = createSprite(0)
setSpritePositionByOffset(spr,320,120)
setSpriteSize(spr,40,6)
setSpritePhysicsOn(spr,2)

type sparkType
    spr as integer
    die as float
endtype
dim spark[0] as sparkType
spark[0].spr = 0
global time as float

do
    time = timer()
    
    rem get sprite data
    sa# = getSpriteAngle(spr)
    sx# = getSpriteXbyOffset(spr)
    sy# = getSpriteYbyOffset(spr)
    
    rem apply angular impulse
    setSpritePhysicsAngularImpulse(spr,8)
    
    rem apply linear impulse
    vx# = cos(sa#)*40
    vy# = -sin(sa#)*40
    setSpritePhysicsImpulse(spr,sx#,sy#,vx#,vy#)
    
    rem sparks
    createSpark(sx#,sy#,-vx#,vy#)
    updateSparks()
    
    sync()
loop

function createSpark(x#,y#,vx#,vy#)
    spr = createSprite(0)
    setSpriteSize(spr,2,-1)
    setSpritePositionByOffset(spr,x#+vx#*0.5,y#+vy#*0.5)
    setSpritePhysicsOn(spr,2)
    setSpritePhysicsVelocity(spr,vx#*2,vy#*2)
    n = spark[0].spr + 1
    dim spark[n] as sparkType
    spark[0].spr = n
    spark[n].spr = spr
    spark[n].die = time + 2.0
endfunction

function updateSparks()
    n = spark[0].spr
    for i=1 to n
        die# = spark[i].die
        spr  = spark[i].spr
        if die#-time>0
            f# = (die#-time)*0.5
            if i=1 then print(str(f#))
            c# = f#*255.0
            setSpriteColor(spr,c#,255.0-c#,0,c#)
        else
            deleteSprite(spr)
            spark[i].spr = spark[n].spr
            spark[i].die = spark[n].die
            dec n
            dec i
            dim spark[n] as sparkType
            spark[0].spr = n
        endif
    next
endfunction

this.mess = abs(sin(times#))

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ICERGB

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Joined: 8th Nov 2002

Location: Canada

Posted: 24th Nov 2012 08:27

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Wow!
That is so sweet, Thanks much for that!

Now I just gotta figure out what is happening...

heheh

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baxslash

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Joined: 26th Dec 2006

Location: Duffield

Posted: 24th Nov 2012 08:38

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If you ignore the sparks it's relatively simple. Just use sin() and cos() and the angle of the sprite to work out your linear forces.

this.mess = abs(sin(times#))

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ICERGB

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Joined: 8th Nov 2002

Location: Canada

Posted: 24th Nov 2012 10:53

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I see that it is still not very friendly to a percentage based coordinate system.
It is pretty reliant on subtle balances to get it spinning properly.
In the percentage based system the particles you created actually help to balance out the twirling.

Any easy way to limit the speed of the spin?

//setVirtualResolution(640,480)
setdisplayaspect (0.66)
CreateText (11," ")
settextsize (11,2)
settextx (11,1)
settexty (11,3)
// SetTextColor( 10, 0,100,0,255)

SetPhysicsGravity(0,0)

spr = createSprite(0)
//setSpritePositionByOffset(spr,320,120)
setSpritePositionByOffset(spr,50,50)

setSpriteSize(spr,10,1)
setSpritePhysicsOn(spr,2)

type sparkType
    spr as integer
    die as float
endtype
dim spark[0] as sparkType
spark[0].spr = 0
global time as float

for i=6 to 35
redrocksnum=40+i
CreateSprite ( redrocksnum,0 )
setspritesize(redrocksnum,random(2,8),-1)
setspritex(redrocksnum,random(1,90))
setspritey(redrocksnum,random(1,60))
SetSpritePhysicsOn (redrocksnum,2)
SetSpritePhysicsRestitution ( redrocksnum, 1.0 )
setspriteangle(redrocksnum,random(1,360))
SetSpriteColor(redrocksnum, 0,0,random(150,255),255)
//setSpritePhysicsAngularImpulse(redrocksnum,random(-3,3))
setSpritePhysicsImpulse(redrocksnum,getSpriteXbyOffset(spr),getSpriteybyOffset(spr),random(-5,5),random(-5,5))

time = timer()

rem get sprite data
    sa# = getSpriteAngle(spr)
    sx# = getSpriteXbyOffset(spr)
    sy# = getSpriteYbyOffset(spr)

rem apply angular impulse
    setSpritePhysicsAngularImpulse(spr,0.3)

rem apply linear impulse
    vx# = cos(sa#)*0.1
    vy# = -sin(sa#)*0.1
    setSpritePhysicsImpulse(spr,sx#,sy#,vx#,vy#)

rem sparks
    createSpark(sx#,sy#,-vx#,vy#)
    updateSparks()

//vartsta$="mass=" + str(mass#)
//settextstring(11,vartsta$)

sync()
loop

function createSpark(x#,y#,vx#,vy#)
    spr = createSprite(0)
    setSpriteSize(spr,0.8,-1)
    setSpritePositionByOffset(spr,x#+vx#*0.5,y#+vy#*0.5)
    setSpritePhysicsOn(spr,2)
    setSpritePhysicsVelocity(spr,vx#*2,vy#*2)
    setspritephysicsmass(spr,0.009)
    n = spark[0].spr + 1
    dim spark[n] as sparkType
    spark[0].spr = n
    spark[n].spr = spr
    spark[n].die = time + 2.0
endfunction

function updateSparks()
    n = spark[0].spr
    for i=1 to n
        die# = spark[i].die
        spr  = spark[i].spr
        if die#-time>0
            f# = (die#-time)*0.5
            if i=1 then print(str(f#))
            c# = f#*255.0
            setSpriteColor(spr,c#,255.0-c#,0,c#)
        else
            deleteSprite(spr)
            spark[i].spr = spark[n].spr
            spark[i].die = spark[n].die
            dec n
            dec i
            dim spark[n] as sparkType
            spark[0].spr = n
        endif
    next
endfunction

+ Code Snippet

//setVirtualResolution(640,480)
setdisplayaspect (0.66)
CreateText (11," ")
settextsize (11,2)
settextx (11,1)
settexty (11,3)
// SetTextColor( 10, 0,100,0,255)

SetPhysicsGravity(0,0)



spr = createSprite(0)
//setSpritePositionByOffset(spr,320,120)
setSpritePositionByOffset(spr,50,50)

setSpriteSize(spr,10,1)
setSpritePhysicsOn(spr,2)

type sparkType
    spr as integer
    die as float
endtype
dim spark[0] as sparkType
spark[0].spr = 0
global time as float


for i=6 to 35
redrocksnum=40+i
CreateSprite ( redrocksnum,0 )
setspritesize(redrocksnum,random(2,8),-1)
setspritex(redrocksnum,random(1,90))
setspritey(redrocksnum,random(1,60))
SetSpritePhysicsOn (redrocksnum,2)
SetSpritePhysicsRestitution ( redrocksnum, 1.0 )
setspriteangle(redrocksnum,random(1,360))
SetSpriteColor(redrocksnum, 0,0,random(150,255),255)
//setSpritePhysicsAngularImpulse(redrocksnum,random(-3,3))
setSpritePhysicsImpulse(redrocksnum,getSpriteXbyOffset(spr),getSpriteybyOffset(spr),random(-5,5),random(-5,5))

next



do
// space key then end
keypressb=GetRawKeyPressed(32)
if keypressb=1
end
endif




    time = timer()

    rem get sprite data
    sa# = getSpriteAngle(spr)
    sx# = getSpriteXbyOffset(spr)
    sy# = getSpriteYbyOffset(spr)

    rem apply angular impulse
    setSpritePhysicsAngularImpulse(spr,0.3)

    rem apply linear impulse
    vx# = cos(sa#)*0.1
    vy# = -sin(sa#)*0.1
    setSpritePhysicsImpulse(spr,sx#,sy#,vx#,vy#)

    rem sparks
    createSpark(sx#,sy#,-vx#,vy#)
    updateSparks()



//vartsta$="mass=" + str(mass#)
//settextstring(11,vartsta$)


    sync()
loop

function createSpark(x#,y#,vx#,vy#)
    spr = createSprite(0)
    setSpriteSize(spr,0.8,-1)
    setSpritePositionByOffset(spr,x#+vx#*0.5,y#+vy#*0.5)
    setSpritePhysicsOn(spr,2)
    setSpritePhysicsVelocity(spr,vx#*2,vy#*2)
    setspritephysicsmass(spr,0.009)
    n = spark[0].spr + 1
    dim spark[n] as sparkType
    spark[0].spr = n
    spark[n].spr = spr
    spark[n].die = time + 2.0
endfunction

function updateSparks()
    n = spark[0].spr
    for i=1 to n
        die# = spark[i].die
        spr  = spark[i].spr
        if die#-time>0
            f# = (die#-time)*0.5
            if i=1 then print(str(f#))
            c# = f#*255.0
            setSpriteColor(spr,c#,255.0-c#,0,c#)
        else
            deleteSprite(spr)
            spark[i].spr = spark[n].spr
            spark[i].die = spark[n].die
            dec n
            dec i
            dim spark[n] as sparkType
            spark[0].spr = n
        endif
    next
endfunction

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ICERGB

22

Years of Service

User Offline

Joined: 8th Nov 2002

Location: Canada

Posted: 24th Nov 2012 11:10 Edited at: 24th Nov 2012 11:31

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Oops think I narrowed in on it...

not sure about the particles coming out of the center instead of the end of the stick now though...

//setVirtualResolution(640,480)
setdisplayaspect (0.66)
CreateText (11," ")
settextsize (11,2)
settextx (11,1)
settexty (11,3)
// SetTextColor( 10, 0,100,0,255)

SetPhysicsGravity(0,0)

spr = createSprite(0)
//setSpritePositionByOffset(spr,320,120)
setSpritePositionByOffset(spr,50,50)

setSpriteSize(spr,10,1)
setSpritePhysicsOn(spr,2)

type sparkType
    spr as integer
    die as float
endtype
dim spark[0] as sparkType
spark[0].spr = 0
global time as float

for i=6 to 35
redrocksnum=40+i
CreateSprite ( redrocksnum,0 )
setspritesize(redrocksnum,random(2,8),-1)
setspritex(redrocksnum,random(1,90))
setspritey(redrocksnum,random(1,60))
SetSpritePhysicsOn (redrocksnum,2)
SetSpritePhysicsRestitution ( redrocksnum, 1.0 )
setspriteangle(redrocksnum,random(1,360))
SetSpriteColor(redrocksnum, 0,0,random(150,255),255)
//setSpritePhysicsAngularImpulse(redrocksnum,random(-3,3))
setSpritePhysicsImpulse(redrocksnum,getSpriteXbyOffset(spr),getSpriteybyOffset(spr),random(-5,5),random(-5,5))

// space key then end
keypressb=GetRawKeyPressed(32)
if keypressb=1
end
endif

time = timer()

rem get sprite data
    sa# = getSpriteAngle(spr)
    sx# = getSpriteXbyOffset(spr)
    sy# = getSpriteYbyOffset(spr)
if angvel#<10
    rem apply angular impulse
    setSpritePhysicsAngularImpulse(spr,0.3)

rem apply linear impulse
    vx# = cos(sa#)*0.1
    vy# = -sin(sa#)*0.1
    setSpritePhysicsImpulse(spr,sx#,sy#,vx#,vy#)
endif
    rem sparks
    createSpark(sx#,sy#,-vx#,vy#)
    updateSparks()

vartsta$="angularvelocity=" + str(angvel#)
settextstring(11,vartsta$)

sync()
loop

function createSpark(x#,y#,vx#,vy#)
    spr = createSprite(0)
    setSpriteSize(spr,0.8,-1)
    setSpritePositionByOffset(spr,x#+vx#*0.5,y#+vy#*0.5)
    setSpritePhysicsOn(spr,2)
    setSpritePhysicsVelocity(spr,vx#*2,vy#*2)
    setspritephysicsmass(spr,0.009)
    n = spark[0].spr + 1
    dim spark[n] as sparkType
    spark[0].spr = n
    spark[n].spr = spr
    spark[n].die = time + 2.0
endfunction

function updateSparks()
    n = spark[0].spr
    for i=1 to n
        die# = spark[i].die
        spr  = spark[i].spr
        if die#-time>0
            f# = (die#-time)*0.5
            if i=1 then print(str(f#))
            c# = f#*255.0
            setSpriteColor(spr,c#,255.0-c#,0,c#)
        else
            deleteSprite(spr)
            spark[i].spr = spark[n].spr
            spark[i].die = spark[n].die
            dec n
            dec i
            dim spark[n] as sparkType
            spark[0].spr = n
        endif
    next
endfunction

+ Code Snippet

//setVirtualResolution(640,480)
setdisplayaspect (0.66)
CreateText (11," ")
settextsize (11,2)
settextx (11,1)
settexty (11,3)
// SetTextColor( 10, 0,100,0,255)

SetPhysicsGravity(0,0)



spr = createSprite(0)
//setSpritePositionByOffset(spr,320,120)
setSpritePositionByOffset(spr,50,50)

setSpriteSize(spr,10,1)
setSpritePhysicsOn(spr,2)

type sparkType
    spr as integer
    die as float
endtype
dim spark[0] as sparkType
spark[0].spr = 0
global time as float


for i=6 to 35
redrocksnum=40+i
CreateSprite ( redrocksnum,0 )
setspritesize(redrocksnum,random(2,8),-1)
setspritex(redrocksnum,random(1,90))
setspritey(redrocksnum,random(1,60))
SetSpritePhysicsOn (redrocksnum,2)
SetSpritePhysicsRestitution ( redrocksnum, 1.0 )
setspriteangle(redrocksnum,random(1,360))
SetSpriteColor(redrocksnum, 0,0,random(150,255),255)
//setSpritePhysicsAngularImpulse(redrocksnum,random(-3,3))
setSpritePhysicsImpulse(redrocksnum,getSpriteXbyOffset(spr),getSpriteybyOffset(spr),random(-5,5),random(-5,5))

next



do
angvel#=getspritephysicsangularvelocity(spr)

// space key then end
keypressb=GetRawKeyPressed(32)
if keypressb=1
end
endif




    time = timer()

    rem get sprite data
    sa# = getSpriteAngle(spr)
    sx# = getSpriteXbyOffset(spr)
    sy# = getSpriteYbyOffset(spr)
if angvel#<10
    rem apply angular impulse
    setSpritePhysicsAngularImpulse(spr,0.3)

    rem apply linear impulse
    vx# = cos(sa#)*0.1
    vy# = -sin(sa#)*0.1
    setSpritePhysicsImpulse(spr,sx#,sy#,vx#,vy#)
endif
    rem sparks
    createSpark(sx#,sy#,-vx#,vy#)
    updateSparks()




vartsta$="angularvelocity=" + str(angvel#)
settextstring(11,vartsta$)


    sync()
loop

function createSpark(x#,y#,vx#,vy#)
    spr = createSprite(0)
    setSpriteSize(spr,0.8,-1)
    setSpritePositionByOffset(spr,x#+vx#*0.5,y#+vy#*0.5)
    setSpritePhysicsOn(spr,2)
    setSpritePhysicsVelocity(spr,vx#*2,vy#*2)
    setspritephysicsmass(spr,0.009)
    n = spark[0].spr + 1
    dim spark[n] as sparkType
    spark[0].spr = n
    spark[n].spr = spr
    spark[n].die = time + 2.0
endfunction

function updateSparks()
    n = spark[0].spr
    for i=1 to n
        die# = spark[i].die
        spr  = spark[i].spr
        if die#-time>0
            f# = (die#-time)*0.5
            if i=1 then print(str(f#))
            c# = f#*255.0
            setSpriteColor(spr,c#,255.0-c#,0,c#)
        else
            deleteSprite(spr)
            spark[i].spr = spark[n].spr
            spark[i].die = spark[n].die
            dec n
            dec i
            dim spark[n] as sparkType
            spark[0].spr = n
        endif
    next
endfunction

can't for the life of me figure out how to get the particles to come out of the top end of the stick.

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