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--线与圆的碰撞
function LineToCircle(linePoint1,linePoint2,circlePos,radius)--这里需要分成两种情况，一种是线段两边的点是否在圆内--如果点到半径的距离if PointToCircle(linePoint1,circlePos,radius) thenreturn trueendif PointToCircle(linePoint2,circlePos,radius) thenreturn trueend--寻找圆心最近的点local lineVec = {x= (linePoint2.x - linePoint1.x) , y = (linePoint2.y - linePoint1.y)}local pointToLinePoint1 = {x= (circlePos.x - linePoint1.x) , y = (circlePos.y - linePoint1.y)}local lineLength = math.sqrt(lineVec.x * lineVec.x  + lineVec.y * lineVec.y)--点乘向量公式 相当于 lineLength * pointLinePoint1Length * cos角度local dot = lineVec.x  * pointToLinePoint1.x +  lineVec.y * pointToLinePoint1.y--这里就是pointLinePoint1Length * cos角度 及为lineVec 的投影长度，温馨提示pointLinePoint1ToLine可能为正负值 取决于向量的夹角的cos值--相当于到线段的投影比例local pointLinePoint1ToLine =  dot / lineLengthlocal closestX = linePoint1.x + pointLinePoint1ToLine * (linePoint2.x - linePoint1.x)local closestY = linePoint1.y + pointLinePoint1ToLine * (linePoint2.y - linePoint1.y)local isInLine = PointToLine({ x = closestX,y =  closestY} , linePoint1, linePoint2)--如果点不在线上面（就是相当于他是在延长线 ） 直接returnfalseif not isInLine thenreturn false;end--点跟圆的碰撞local result = PointToCircle({ x = closestX,y =  closestY},circlePos,radius)return result
end

--点与直线的碰撞
function PointToLine(point , linePoint1, linePoint2)--思想点与线两边线段的距离跟线的距离的判断，相等就是在同一直线local line1 = math.sqrt((linePoint1.x - point.x) * (linePoint1.x - point.x) + (linePoint1.y - point.y)* (linePoint1.y - point.y))local line2 = math.sqrt((linePoint2.x - point.x) * (linePoint2.x - point.x) + (linePoint2.y - point.y)* (linePoint2.y - point.y))local line = math.sqrt((linePoint2.x - linePoint1.x) * (linePoint2.x - linePoint1.x) + (linePoint2.y - linePoint1.y)* (linePoint2.y - linePoint1.y))return (line1 + line2) == line
end

--点跟圆是否碰撞
function PointToCircle (point,circlePos,radius)local sqr2  = (point.x - circlePos.x) * (point.x - circlePos.x) + (point.y - circlePos.y) * (point.y - circlePos.y)return radius * radius >= sqr2
end