Gear drawing- and animation

This started with wondering how easy it is to draw convincing gear teeth- although the shape I made is not the correct smooth-meshing profile. Then I moved on to animating meshing gears, cheating by saving successive stills then making the animaed GIF.

OK got meshing working... if a little flashy when running.

    nomainwin

    global hdc, pi

    WindowWidth  =600
    WindowHeight =600

    open "test" for graphics_nsb_nf as #gr

    #gr "trapclose [quit]"
    #gr "down"

    targetcolor     =0  '   this is the colour of the outline to fill out to.
    c               =0

    hw      =hwnd( #gr)    '                                    <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
    calldll #user32, "GetDC", hw as ulong, hdc as ulong    '    <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

    pi      =acs( -1)

    #gr "cls ; down ; fill 180 180 60 ; up ; size 2"

    phase =0

    do

        #gr "cls ; down ; fill 180 180 180 ; up ; color 0 0 0"

        call gear 385, 210, 30, "255 180 60", phase, "CCW"
        call gear 107, 229, 15, "230 160 80", phase, "CW"

        #gr "flush"

        #gr "getbmp drawing 1 1 580 570"
        bmpsave "drawing", "meshing" +right$( "000" +str$( c), 3) +".bmp"
        c       =c +1

        scan

        calldll #kernel32, "Sleep", 200 as long, ret as void

        phase   =phase +pi /10

    loop until phase >2 *pi

    wait

    sub gear xPos, yPos, numTeeth, phillCol$, phase, sense$
        calcdRadius =int( numTeeth *6)
        ratio       =1'30 /numTeeth

        r       =calcdRadius +10 *sin( numTeeth *phase)
        #gr "up ; goto "; xPos +r *cos( phase); " "; yPos +r *sin( phase)

        for phi =0 to 2 *pi +0.1 step 0.02
            r   =calcdRadius +15 *sin( numTeeth *phi +phase *ratio)

            if sense$ ="CW" then
                x   =xPos +r *cos( phi)
                y   =yPos +r *sin( phi)
            else
                x   =xPos +r *cos( phi)
                y   =yPos -r *sin( phi)
            end if

            #gr "goto "; int( x); " "; int( y)
            #gr "down"
            'calldll #kernel32, "Sleep", 2 as long, ret as void

        next phi

        #gr "backcolor 200 200 200"
        #gr "up ; goto "; xPos; " "; yPos; " ; down ; circlefilled 10"
        xVar =xPos +20
        yVar =yPos

        #gr "backcolor "; phillCol$

        calldll #gdi32, "ExtFloodFill",_
            hdc                as ulong,_
            xVar               as long,_
            yVar               as long,_
            targetcolor        as long,_
            _FLOODFILLBORDER   as long,_    '       '   ie fill out 'til targetcolour is met
            result             as long

        #gr "up"
    end sub

[quit]
    close #gr
    calldll #user32, "ReleaseDC", hw as ulong, hdc as ulong, ret as void   'release the DC    <<<<<<<<<<<<<<<<<<<<<
    end