Searching for some UV calculations

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haliop_New

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Posted: 24th Oct 2014 18:43

searched google it didnt gave me alot maybe im searching for the wrong thing

i want to change my sprite UV in order to create a real time flag like effect..

any ideas ?

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unlikely

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Posted: 24th Oct 2014 18:56

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You can control a sprite's UV coords using SetSpriteUV() or SetSpriteUVOffset(). If you use the SetImageWrapU() and SetImageWrapV() commands, you can control the clamping or wrapping behavior of the coordinates on a per image basis. I think you should be able to achieve what you're looking for.

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Markus

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Posted: 24th Oct 2014 21:39 Edited at: 24th Oct 2014 21:44

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uv is same as xy,
u can input a running value in sin or cos
angle=angle+1
if angle>360 then angle=angle-360
newvalue = sin(angle) * value
this make a sin wave.

this uv for a sqare image
left top is 0,0
right top is 1,0
right bottom is 1,1
left bottom is 0,1

a single sprite have only 4 points, think SpriteUV did not work.

AGK 108 (B)19 + AppGameKit V2 Alpha .. : Windows 8.1 Pro 64 Bit : AMD Radeon R7 265 : Mac mini

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Markus

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Posted: 24th Oct 2014 21:46 Edited at: 24th Oct 2014 21:46

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this here is based on more sprites, maybe u can use.

rem
rem AGK Application 1.08 19
rem MR 23.08.2013 Screen Wave

SetDisplayAspect( 4.0/3.0 )

dim i[100]
dim s[100]

MainLoop()
end

function MainLoop()

sync()
    spr=loadsprite("screen.png")  //<- any background image
    setspritesize(spr,100,100)
    drawsprite(spr)
    MakeWave()
    deletesprite(spr)

w#=0

do
     print("Hello Wave")
     print(screenfps())

DoWave(w#)

w#=w#+360.0/60.0
     if w#>360.0 then w#=w#-360.0

if getpointerpressed()=1 then exit

Sync()
    loop

FreeWave()

endfunction

function MakeWave()

for y=0 to 99
     i[y]=GetImage( 0, y,getvirtualwidth(), 1.0 )
     s[y]=createsprite(i[y])
     setspritesize(s[y],getvirtualwidth(),1.5)
     setspriteposition(s[y],0,y)
     setspritedepth(s[y],0)
    next

endfunction

function DoWave(w#)

for y=0 to 99
     setspriteposition(s[y],cos(w#),y+sin(w#)*4.0)
     w#=w#+360.0/100.0
    next

endfunction

function FreeWave()

for y=0 to 99
     deletesprite(s[y])
     s[y]=0
     deleteimage(i[y])
     i[y]=0
    next

endfunction

+ Code Snippet

rem
rem AGK Application 1.08 19
rem MR 23.08.2013 Screen Wave

SetDisplayAspect( 4.0/3.0 )

dim i[100]
dim s[100]

MainLoop()
end

function MainLoop()

    sync()
    spr=loadsprite("screen.png")  //<- any background image
    setspritesize(spr,100,100)
    drawsprite(spr)
    MakeWave()
    deletesprite(spr)

    w#=0

    do
     print("Hello Wave")
     print(screenfps())

     DoWave(w#)

     w#=w#+360.0/60.0
     if w#>360.0 then w#=w#-360.0

     if getpointerpressed()=1 then exit

     Sync()
    loop

    FreeWave()

endfunction

function MakeWave()

    for y=0 to 99
     i[y]=GetImage( 0, y,getvirtualwidth(), 1.0 )
     s[y]=createsprite(i[y])
     setspritesize(s[y],getvirtualwidth(),1.5)
     setspriteposition(s[y],0,y)
     setspritedepth(s[y],0)
    next

endfunction

function DoWave(w#)

    for y=0 to 99
     setspriteposition(s[y],cos(w#),y+sin(w#)*4.0)
     w#=w#+360.0/100.0
    next

endfunction

function FreeWave()

    for y=0 to 99
     deletesprite(s[y])
     s[y]=0
     deleteimage(i[y])
     i[y]=0
    next

endfunction

AGK 108 (B)19 + AppGameKit V2 Alpha .. : Windows 8.1 Pro 64 Bit : AMD Radeon R7 265 : Mac mini

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unlikely

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Posted: 25th Oct 2014 00:21

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Okay, I see what you're looking for haliop. An actual 3d flag like effect. I was assuming you were just trying to scroll a flag texture to make it appear like it's "waving".

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Markus

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Posted: 25th Oct 2014 00:36

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a pre rendered animation should also work but take much of memory and
loading time.

AGK 108 (B)19 + AppGameKit V2 Alpha .. : Windows 8.1 Pro 64 Bit : AMD Radeon R7 265 : Mac mini

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haliop_New

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Posted: 25th Oct 2014 09:05

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thank you markus but that is not what im after cause you actually create and regenerate new sprites on the fly which i think is a waste of system usage..
i found the Grass tutorial presented here in the forum , but i cant really figure out what to do with the UV , you said Sin for wave right? maybe a bit more explanation about that if you can will be very helpfull.

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Markus

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Posted: 25th Oct 2014 12:57

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i know olny to do effect in 3d with moving the vertieces.
i had unsterstand you want make a flag that moving in wind / breeze.

Quote: "create and regenerate new sprites on the fly "

not, this "do wave" only change the position.
instead of 1 sprites - i used more smaller sprites.

AGK 108 (B)19 + AppGameKit V2 Alpha .. : Windows 8.1 Pro 64 Bit : AMD Radeon R7 265 : Mac mini

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haliop_New

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Posted: 25th Oct 2014 19:20

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ahh ok you create 100 sprites at startup then only moving them but then again using 100 sprites is too much , so still i think if i could manipulate the UV choords like this example it will be best efficient cause what if i want to present 10 flags or flag like items on one screen at the same time.. then you aiming at high sprite usage which is kinda of problem as i already present thousands of sprites ...

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haliop_New

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Posted: 25th Oct 2014 19:26

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you know what i think i'll use it for now , i reduced it to 5 sprites and still it looks neat , thank you markus.

btw what should i change if i want it to wave sideways rather then upwards?

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Markus

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Posted: 25th Oct 2014 19:53

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the make wave cut from left to right,
and do wave setspriteposition(s[y],y+sin(w#)*4.0,cos(w#))
the look there i had use y, from left to right its x

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fog

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Posted: 25th Oct 2014 22:45

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Provided you're using V2 then a single sprite and a simple shader would be the easiest and most efficient way to do it.

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haliop_New

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Posted: 26th Oct 2014 06:46

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markus i tried that exactly but it went weird

fog please explain, i know very little about shaders
so you are suggesting i'll add a shader to that sprite which sounds even better then UV calcs and since the game is aimed for windows thinking that most pc's have a decent gpu capabilities it might be the best solution.

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