iphone grab sprite

[djtoon]

hi
any ideas why grab sprite on a wight png on the iphone turns out blank?

[Kitty Hello]

no. But Grabsprite _might_ not be working on iOS. I'm almost certain that it does, though.

Can you try CREATESCREEN instead, or do you really rely on Grabsprite? If so, make a small sample project that illustrates the error.

[Crivens]

It definitely works because that is what I use in my app to break a picture into multiple sprites (tile slider game).

Cheers

[djtoon]

it works but :

i load 4 images with wight background aand grab sprite them

1 works ok
the second the wight is transperent
and the third and fourth are ok too

weird.
the images all have 255,255,255 background i chk'd in photoshop

[Kitty Hello]

Before you draw to the back-buffer, draw a rectangle with a solid colour to set/clear the alpha values. (Or call CLEARSCREEN with the colour you want).
Also call SETTRANSPARENCY before the drawing to be sure you don't draw transparent if you don't want it.

[djtoon]

well dosent work
here is my function




FUNCTION loadpages:pageN

CLEARSCREEN RGB(255,255,255)

LOADSPRITE "Media/p"+pageN+".bmp",0

LOCAL s=pageN+1
LOADSPRITE "Media/p"+s+".bmp",3

LOCAL s=pageN-1
LOADSPRITE "Media/p"+s+".bmp",4


DRAWRECT 0,0,sw,sh,RGB(255,255,255)
STRETCHSPRITE 4, 240, 0, -480, 320
GRABSPRITE 1,0,0,480,320



DRAWRECT 0,0,sw,sh,RGB(0,255,0)
DRAWSPRITE 3,0,0

GRABSPRITE 2,240,0,240,320

ENDFUNCTION

[Kitty Hello]

I'm not sure if I understand your code properly.

See this - and check your STRETCHSPRITE and GRABSPRITE rectangle parameters.

Code (glbasic) Select Expand



SYSTEMPOINTER TRUE

// Make 0-5 images
CREATESCREEN 0,77, 64,64
FOR i=0 TO 5
USESCREEN 0
DRAWRECT 0,0,64,64,0xffffff
PRINT i, 10,10
USESCREEN -1
SAVESPRITE "Media/p"+i+".bmp", 77
NEXT


// Load and display them
loadpages(2)

CLEARSCREEN 0

FOR j=0 TO 4
PRINT "SpID:" +j, j*70,0
VIEWPORT j*70,33,64,64
DRAWSPRITE j, 0, 0
VIEWPORT 0,0,0,0
NEXT
SHOWSCREEN
MOUSEWAIT






FUNCTION loadpages:pageN
LOCAL sw%, sh%
GETSCREENSIZE sw, sh


CLEARSCREEN RGB(255,255,255) // makes white transparent

LOADSPRITE "Media/p"+pageN+".bmp",0 // 0=oiriginal

LOCAL s=pageN+1
LOADSPRITE "Media/p"+s+".bmp",3     // 3=next

LOCAL s=pageN-1
LOADSPRITE "Media/p"+s+".bmp",4     // 4=previous


DRAWRECT 0,0,sw,sh,RGB(255,255,255) // draw transparent white rect -> won't draw anything
STRETCHSPRITE 4, 64, 0, -64, 64
GRABSPRITE 1,0,0,480,320            // 1=mirrored previous(4)



DRAWRECT 0,0,sw,sh,RGB(0,255,0)
DRAWSPRITE 3,0,0

GRABSPRITE 2,0,0,64,64          // 2=next on green bkgnd

ENDFUNCTION


Should output:
[2] [1(flipped)] [3] [3] [1]

[djtoon]

does create screen work on iphone?

[Slydog]

Just a long shot, I never tried your code, but you have the 's' variable being declared twice:

Code (glbasic) Select Expand

LOCAL s=pageN+1
LOADSPRITE "Media/p"+s+".bmp",3

LOCAL s=pageN-1            // 2nd time, remove 'LOCAL'
LOADSPRITE "Media/p"+s+".bmp",4

Or remove it all together and try this instead:

Code (glbasic) Select Expand

LOADSPRITE "Media/p" + (pageN+1) + ".bmp",3
LOADSPRITE "Media/p" + (pageN-1) + ".bmp",4

Also, just to be safe, I'd declare the 'pageN' float as integer, using 'FUNCTION loadpages:pageN%'.
Just in case a rouge decimal rounding causes a weird filename.  (just being cautious)

[Kitty Hello]

createscreen also works, yes.