Angle Collisions

[bplus]

Here is my circle intersect line segment detector, thanks to james2464 Random Line Segment Container Problem which I had to create to detect when a ball enters a line segment:

Code: (Select All)

' return count of how many points overlap segment
Function lineSegIntersectCircle (x1, y1, x2, y2, cx, cy, r)
    ' x1, y1 and x2, y2  are end points of line segment
    ' cx, cy are circle center with radius r
    Dim rtn, i
    Dim As Double d, dx, dy, x, y

    d = Sqr((x1 - x2) ^ 2 + (y1 - y2) ^ 2)
    dx = (x2 - x1) / d
    dy = (y2 - y1) / d
    For i = 0 To d  ' this effectively redraws the line point by point without actually drawing it on screen
        x = x1 + dx * i
        y = y1 + dy * i
        If Sqr((x - cx) ^ 2 + (y - cy) ^ 2) <= r Then rtn = rtn + 1
         'if this point is in radius range then it is in intersection of circle and line segment
    Next
    lineSegIntersectCircle = rtn
End Function