Linear Path Tracker

 

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A sprite dragged and dropped in any place on the screen traces its path back to its starting point in a linear path i.e in a straight line. This path is shown by a white line that is drawn along the path of the sprite.

--A sprite dragged and dropped in any place on the screen traces its path back to its starting point in a linear path i.e in a straight line. This path is shown by a white line that is drawn along the path of the sprite. --This algorithm is based on the Simple Digital Differential Analyzer(Simple DDA). --It is an incremenal method of drawing a line where each xunit and yunit coordinates to be plotted is incremented or decremented by a displacement value, dx and dy. Here, dx = dx and dy = dy . --The starting position (coordinates) of the sprite is assigned as gx2 = 320 and gy2 = 240 --It must be understood here that gx2 will be the loch value and gy2 is the locv value to which the sprite traces its path back. These values may be changed in the startmovie or the users may provide a more interactive way of getting the values. global gx1 global gy1 global gx2 global gy2 global lenest -- Line Length estimate global dx global dy -- Incremental Values global xunit -- Unit step generated in X-axis global yunit -- Unit step generated in Y-axis on startmovie   set the moveablesprite of sprite 2 to true   updatestage   member("org").duplicate(4)   set the name of member 4 to "imgb"   gx1 = 0   gy1 = 0   gx2 = 320   gy2 = 240   lenest = 0   xunit = 0   yunit = 0   dx = 0.000   dy = 0.000   the floatprecision = 3 end ------------------------------------------------------------------------------------------------ global gx1 global gy1 global gx2 global gy2 global lenest global dx global dy global xunit global yunit on mouseUp   -- Simple DDA implementation.   -- It generates unit steps in the direction of the largest motion.   gx1 = the loch of sprite 2   gy1 = the locv of sprite 2   lenest = abs(gx2-gx1)   if abs(gy2-gy1) > lenest then lenest = abs(gy2-gy1)   dx = (abs(float(gx2)-float(gx1)))/lenest   dy = (abs(float(gy2)-float(gy1)))/lenest   xunit = gx1 + 0.5   yunit = gy1+ 0.5   repeat with i = 1 to lenest     set the loc of sprite 2 to point(xunit,yunit)     updatestage     member("imgb").image.setPixel(xunit, yunit, rgb(255,255,255))     if gx1 > gx2 and gy1 < gy2 then       xunit = xunit - dx       yunit = yunit + dy     else if gx1 < gx2 and gy1 < gy2 then       xunit = xunit + dx       yunit = yunit + dy     else if gx1 > gx2 and gy1 > gy2 then       xunit = xunit - dx       yunit = yunit - dy     else if gx1 < gx2 and gy1 > gy2 then       xunit = xunit + dx       yunit = yunit - dy     end if   end repeat   set the loc of sprite 2 to point(320,240)   updatestage end