Recursively extracting sprites

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' Parse a sprite sheet concept

'

' Issues to overcome:

' - Individual pixels are seen as separate sprites (the last 5 sprites in image)

'   Somehow the code needs to intelligently decide that these pixels belong to a sprite

'



TYPE XY

    x AS INTEGER

    y AS INTEGER

END TYPE



DIM Min AS XY '                    minimum x,y values seen

DIM Max AS XY '                    maximum x,y values seen

DIM Background AS _UNSIGNED LONG ' background color to use as border

DIM Pixel AS _UNSIGNED LONG '      pixel color

DIM SourceSheet AS LONG '          source image containing sprites

DIM TargetSheet AS LONG '          target image to write found sprites to

DIM x AS INTEGER '                 horizontal coordinate counter

DIM y AS INTEGER '                 vertical coordinate counter



SourceSheet = _LOADIMAGE("demon.png", 32) '                              load source sprite sheet

TargetSheet = _NEWIMAGE(_WIDTH(SourceSheet), _HEIGHT(SourceSheet), 32) ' create target sprite sheet

SCREEN _NEWIMAGE(781, 720, 32) '                                         create view screen

CLS

Background = _RGB32(255, 0, 255) '                                       background border color (bright magenta)

_SOURCE SourceSheet '                                                    get pixel data from source image



y = 0 '     reset vertical counter

DO

    x = 0 ' reset horizontal counter

    DO



        ' scan right until a pixel is found



        Pixel = POINT(x, y) '          get pixel color

        IF Pixel <> Background THEN '  is this pixel part of a sprite?



            ' A pixel has been found



            Min.x = x ' set starting point of min/max x,y values seen

            Max.x = x

            Min.y = y

            Max.y = y



            GrabSprite x, y, SourceSheet, TargetSheet, Background ' recursively get sprite



            ' Now the sprite has been written to the target image and the min/max x,y coordinates are known

            ' Grab the written sprite as you wish and then remove it from the target sheet



            ' This nethod would work just as well if for instance the mouse pointer was used to click

            ' anywhere inside of a sprite to extract it.



            ' Quick code to show the concept in action



            _DEST 0

            _PUTIMAGE (0, 0), SourceSheet

            _PUTIMAGE (0, 360), TargetSheet

            LOCATE 1, 1

            PRINT Max.x - Min.x, Max.y - Min.y ' current sprite dimensions

            _LIMIT 5 ' slow down to see progress

        END IF

        x = x + 1

    LOOP UNTIL x = _WIDTH(SourceSheet)

    y = y + 1

LOOP UNTIL y = _HEIGHT(SourceSheet)







SUB GrabSprite (x AS INTEGER, y AS INTEGER, s AS LONG, t AS LONG, Border AS _UNSIGNED LONG)



    ' Recursively grabs an image within the border color specified (proof of concept)

    ' (Based on flood fill)



    ' x,y - pixel coordinate

    ' s   - source image

    ' t   - target image

    ' b   - border (background) color



    SHARED Min AS XY

    SHARED Max AS XY

    DIM Pixel AS _UNSIGNED LONG



    IF x = -1 OR y = -1 OR x = _WIDTH(s) OR y = _HEIGHT(s) THEN EXIT SUB ' leave if x,y outside of source image

    _SOURCE s '                             get from source image

    Pixel = POINT(x, y) '                   get pixel color

    IF Pixel = Border THEN EXIT SUB '       leave if pixel is border color

    _DEST t '                               draw on target image

    PSET (x, y), Pixel '                    copy pixel to target image

    _DEST s '                               draw on source image

    PSET (x, y), Border '                   remove pixel from source image



    MinMax x, y, Min, Max '                 get x and y extremes seen



    GrabSprite x - 1, y, s, t, Border '     examine surrounding pixels

    GrabSprite x + 1, y, s, t, Border

    GrabSprite x, y - 1, s, t, Border

    GrabSprite x, y + 1, s, t, Border

    GrabSprite x - 1, y - 1, s, t, Border

    GrabSprite x - 1, y + 1, s, t, Border

    GrabSprite x + 1, y - 1, s, t, Border

    GrabSprite x + 1, y + 1, s, t, Border



END SUB





SUB MinMax (x AS INTEGER, y AS INTEGER, min AS XY, max AS XY)



    IF x < min.x THEN

        min.x = x

    ELSEIF x > max.x THEN

        max.x = x

    END IF

    IF y < min.y THEN

        min.y = y

    ELSEIF y > max.y THEN

        max.y = y

    END IF



END SUB

Print " " Print " ****** ******* ******* ******* " Print " * * * * * " Print " * * * * * " Print " ****** ***** * **** " Print " * * * * " Print " * * * * " Print " * ******* * ******* " Print " " Locate 1, 1 Do Do Until Pos(0) = _Width If Screen(CsrLin, Pos(0)) <> 32 Then Exit Do Locate , Pos(0) + 1 Loop y1 = CsrLin: x1 = Pos(0) If pixel = 0 Then If x1 < _Width Then pixel = -1: start_row = CsrLin Locate CsrLin + 1, 1 Loop Until y1 > 1 And x1 = _Width And pixel = -1 Or CsrLin = _Height If pixel And x1 = _Width Then sprite_height = CsrLin - start_row - 1 col = 0 Do col = col + 1: pixel = 0 Locate start_row, col For i = 1 To sprite_height If Screen(CsrLin, col) <> 32 Then pixel = -1 If sprite_1_start_col = 0 Then sprite_1_start_col = col: Exit For End If Locate CsrLin + 1, col Next Loop Until sprite_1_start_col And pixel = 0 Or col = _Width If col < _Width Then sprite_1_end_col = col - 1 End If Do col = col + 1: pixel = 0 Locate start_row, col For i = 1 To sprite_height If Screen(CsrLin, col) <> 32 Then pixel = -1 If sprite_2_start_col = 0 Then sprite_2_start_col = col: Exit For End If Locate CsrLin + 1, col Next Loop Until sprite_2_start_col And pixel = 0 Or col = _Width If col < _Width Then sprite_2_end_col = col - 1 End If fac_1 = sprite_1_start_col / 2 fac_2 = (sprite_2_start_col + (sprite_2_end_col - sprite_2_start_col) / 2) - (sprite_1_start_col + (sprite_1_end_col - sprite_1_start_col) / 2) Do View Print: Locate 12, 1: Print Space$(_Width); Locate 12, 1 Input "Select to retrieve a sprite from sprite sheet (1 - 4): "; sel View Print 13 To _Height: Cls 2 x = fac_1 + (sel - 1) * fac_2 y = start_row For i = start_row To start_row + sprite_height For j = x To x + fac_2 If Screen(i, j) <> 32 Then Locate 15 + i - start_row, 4 + j - ((sel - 1) * fac_2): Print "*"; Next Next Loop

Code: (Select All)

' Terry's sprite sheet demon.png is 781 X 360

' there are 11 images across 781 / 11 = 71 exactly

' thereare 6 images down 360 / 6 = 60

' Hence each image should be 71 X 60



' Let's check that!



Screen _NewImage(800, 600, 32)

_ScreenMove 240, 70



D& = _LoadImage("demon.png", 32)

_PutImage (0, 0), D&, 0 ' OK (finally?)



'For x = 0 To 780 Step 71

'    Line (x, 0)-(x, 359),

'Next

'For y = 0 To 359 Step 60

'    Line (0, y)-(780, y)

'Next

' looks good

Sleep

Dim i&(0 To 57)

For j = 0 To 57

    col = j Mod 11

    row = Int(j / 11)

    i&(j) = _NewImage(71, 60, 32)

    _PutImage , 0, i&(j), (col * 71, row * 60)-Step(70, 59)

Next

'Cls

For j = 0 To 57

    Cls

    _PutImage (0, 0), i&(j), 0

    _PrintString (22, 70), Str$(j)

    Sleep

Next