XProfan

English

p.specht

Gray hair emerged with the Umsetzung from C++: in the Demoprogramm go The Endpunkte the lines in the Hauptteil each via Zufallsgenerator definiert. lying these spots but very over- or next to each other (or solely 1 pixel Difference), watts in the Innenschleife The Abbruchbedingung ("Geclippte line lying now complete inside the Sichtfenster-Rechtecks") never More access. the C++ paragon supplied with the Division two Integervariablen namely automatically a Integer-worth back. XProfan-11.2a free attempts with Using the conventional Division but, very To his and supply a Floatwert - The cause for the strange Fehlerverhalten. After substitute the / Operators by the antiquated function @div&(a&,b&) or. by the \ - Integerdivisionszeichen functions now everything. interestingly would a Beschleunigung through Inline-Assemblercode. so remaining it only a demonstration.
greeting

P.s.: there's in the meantime plenty faster, hardwareunterstützte take action, The undertow. "Saturation-Arithmetik"!

Compile Mark Separation

' Cohen-Sutherland Clipping demonstration
' No Liability, usage on Own menace!
' P. woodpecker 2011-01 for Paule´s PC Forum
' Note: there's meanwhile already plenty faster Algorithms!
Def %CLIPLEFT  1'  binary   0001
Def %CLIPRIGHT 2'          0010
Def %CLIPLOWER 4'          0100
Def %CLIPUPPER 8'          1000
Def %TRUE 1
Def %FALSE 0

Proc ClipLine

    var k1%=0
    var k2%=0
    declare dx&,dy&
    dx&=x2&-x1&
    dy&=y2&-y1&
    y1Test
    y2Test
    '  Loop to Cohen/Sutherland, The maximum 2 times through becomes

    while k1% OR k2%

        rtn% = %TRUE

        if k1% & k2% : rtn% = %FALSE : BREAK : endif

            if k1%

                if k1% & %CLIPLEFT

                    y1& = y1& + (XMin&-x1&)*dy&\dx&
                    x1& = XMin&

                elseif k1% & %CLIPRIGHT

                    y1& = y1& + (XMax&-x1&)*dy&\dx&
                    x1& = XMax&

                endif

                if k1% & %CLIPLOWER

                    x1& = x1& + (YMin&-y1&)*dx&\dy&
                    y1& = YMin&

                elseif k1% & %CLIPUPPER

                    x1& = x1& + (YMax&-y1&)*dx&\dy&
                    y1& = YMax&

                endif

                k1% = 0
                y1Test

            endif

            if k1% & k2% : rtn% = %FALSE : BREAK : endif

                if k2%

                    if k2% & %CLIPLEFT

                        y2& = y2& + (XMin&-x2&)*dy&\dx&
                        x2& = XMin&

                    elseif k2% & %CLIPRIGHT

                        y2& = y2& + (XMax&-x2&)*dy&\dx&
                        x2& = XMax&

                    endif

                    if k2% & %CLIPLOWER

                        x2& = x2& + (YMin&-y2&)*dx&\dy&
                        y2& = YMin&

                    elseif k2% & %CLIPUPPER

                        x2& = x2& + (YMax&-y2&)*dx&\dy&
                        y2& = YMax&

                    endif

                    k2% = 0
                    y2Test

                endif

            EndWhile

            return rtn%

        ENDPROC

        proc y1Test

            if y1&<YMin&

                k1% = %CLIPLOWER

            elseif y1& > YMax&

                k1% = %CLIPUPPER

            endif

            if x1& < XMin&

                k1% = k1% | %CLIPLEFT

            elseif x1&>XMax&

                k1% = k1% | %CLIPRIGHT

            endif

        endproc

        proc y2Test

            if y2&<YMin&

                k2% = %CLIPLOWER

            elseif y2&>YMax&

                k2% = %CLIPUPPER

            endif

            if x2&<XMin&

                k2% = k2% | %CLIPLEFT

            elseif (x2&>XMax&)

                k2% = k2% | %CLIPRIGHT

            endif

        endproc

        'INIT
        Declare XMax&,YMax&,XMin&,YMin&,rtn%
        Declare x1&,y1&,x2&,y2&,colo&
        RANDOMIZE
        Window Title "Cohen/Sutherland Clipping Demo"
        Window Style  4 | 8 | 16
        'MAIN

        WHILE 1

            XMin& = Rnd(300)
            YMin& = Rnd(200)
            XMax& = XMin& + Rnd(500)
            YMax& = YMin& + Rnd(250)
            CLS
            colo&=rgb(rnd(256),rnd(256),rnd(256))
            USEP 0,3,colo&
            rectangle XMin&,YMin& - XMax&,YMax&
            'print XMin&,YMin&,XMax&,YMax&

            WhileLoop 1000

                x1& = rnd(Width( %HWnd))
                y1& = rnd(Height(%Hwnd))
                x2& = rnd(Width( %HWnd))
                y2& = rnd(Height(%Hwnd))
                colo&=rgb(rnd(256),rnd(256),rnd(256))
                USEP 3,1,colo&
                Line x1&,y1& - x2&,y2&

                if ClipLine()

                    USEP 0,3,colo&
                    Line x1&,y1& - x2&,y2&

                endif

            EndWhile

        ENDWHILE

        END