Question

一条直线与一个以C (cx,cy)为中心，半径为r的圆相交。该线由位置P (px, py)和方向D (dx, dy)描述。 P位于圆内，直线无限长。 d到交点的距离P是多少？

float Intersect(Vector2d C, float r, Vector2d P, Vector2d D){

    ...

    return d;
}

Answer 1

您可以展开括号并求解未知[ { "eventType": "VIEW_CLICKED", "timestamp": 1560409968465, "replacementText": "", "actionCode": -1, "delayTime": 0, "canScrollTo": false, "elementDescriptors": [ { "className": "android.widget.RelativeLayout", "recyclerViewChildPosition": 2, "adapterViewChildPosition": -1, "groupViewChildPosition": -1, "resourceId": "com.example.myapplication:id/layoutAccounts", "contentDescription": "", "text": "" }, { "className": "android.support.v7.widget.RecyclerView", "recyclerViewChildPosition": -1, "adapterViewChildPosition": -1, "groupViewChildPosition": 0, "resourceId": "com.example.myapplication:id/Primary_recycler_view", "contentDescription": "", "text": "" }, { "className": "android.widget.RelativeLayout", "recyclerViewChildPosition": -1, "adapterViewChildPosition": -1, "groupViewChildPosition": 0, "resourceId": "com.example.myapplication:id/relative2", "contentDescription": "", "text": "" } ] }, { "eventType": "VIEW_CLICKED", "timestamp": 1560409976951, "replacementText": "", "actionCode": -1, "delayTime": 0, "canScrollTo": false, "elementDescriptors": [ { "className": "android.widget.RelativeLayout", "recyclerViewChildPosition": 15, "adapterViewChildPosition": -1, "groupViewChildPosition": -1, "resourceId": "com.example.myapplication:id/layoutAccounts", "contentDescription": "", "text": "" }, { "className": "android.support.v7.widget.RecyclerView", "recyclerViewChildPosition": -1, "adapterViewChildPosition": -1, "groupViewChildPosition": 0, "resourceId": "com.example.myapplication:id/Primary_recycler_view", "contentDescription": "", "text": "" }, { "className": "android.widget.RelativeLayout", "recyclerViewChildPosition": -1, "adapterViewChildPosition": -1, "groupViewChildPosition": 0, "resourceId": "com.example.myapplication:id/relative2", "contentDescription": "", "text": "" } ] }, { "eventType": "VIEW_CLICKED", "timestamp": 1560409984752, "replacementText": "", "actionCode": -1, "delayTime": 0, "canScrollTo": false, "elementDescriptors": [ { "className": "android.widget.RelativeLayout", "recyclerViewChildPosition": 25, "adapterViewChildPosition": -1, "groupViewChildPosition": -1, "resourceId": "com.example.myapplication:id/layoutAccounts", "contentDescription": "", "text": "" }, { "className": "android.support.v7.widget.RecyclerView", "recyclerViewChildPosition": -1, "adapterViewChildPosition": -1, "groupViewChildPosition": 0, "resourceId": "com.example.myapplication:id/Primary_recycler_view", "contentDescription": "", "text": "" }, { "className": "android.widget.RelativeLayout", "recyclerViewChildPosition": -1, "adapterViewChildPosition": -1, "groupViewChildPosition": 0, "resourceId": "com.example.myapplication:id/relative2", "contentDescription": "", "text": "" } ] } ]的二次方程式：

如果对((px - cx) + t * dx)^2 + ((py - cy) + t * dy)^2 = r^2向量进行了归一化（单位长度），则需要(dx,dy)（如果您的线是真正的光线从圆圈开始，则为正根）的距离。

交点公式（当前语句中不需要）

在线圆相交处找到距离

1 个答案: