直线与平面交点

GMath.cpp

@@ -1132,3 +1132,24 @@ GVector3 GPlane::GetNormal() const
 {
 	return n;
 }
+
+float dist(const GPlane & pi, const GPoint3 & p)
+{
+	float D;
+	D = (p*pi.n + pi.d) / norm(pi.n);
+	return D;
+}
+
+bool intersect_line_plane(GPoint3 & p, const GLine & l, const GPlane & pi)
+{
+	//如果直线的方向和平面的法线垂直，则直线和平面平行，没有交点
+	if (EQ_ZERO((l.v*pi.n), PRECISION)) {
+		return false;
+	}
+
+	float t = -(l.p*pi.n + pi.d) / (l.v * pi.n);
+
+	p = l(t);
+
+	return true;
+}

GMath.h

@@ -226,6 +226,8 @@ public:
 
 	bool IsOnLine(const GPoint3& q);
 	friend float dist(const GPoint3& q, const GLine& l);
+
+	friend bool intersect_line_plane(GPoint3& p, const GLine& l, const GPlane& pi);
 };
 
 class GPlane {
@@ -241,4 +243,8 @@ public:
 
 	GPlane& operator =(const GPlane& rhs);
 	GVector3 GetNormal() const;
+
+	friend float dist(const GPlane& pi, const GPoint3& p);
+
+	friend bool intersect_line_plane(GPoint3& p, const GLine& l, const GPlane& pi);
 };

main.cpp

@@ -2,11 +2,14 @@
 
 int main() {
 
-	GPlane PI1(GVector3(0.0f, 0.0f, 1.0f), GPoint3(0.0f, 0.0f, 0.0f));
-	GPlane PI2(GPoint3(1.0,0.0f,0.0f), GPoint3(0.0, 1.0f, 0.0f), GPoint3(0.0, 0.0f, 1.0f));
+	GPlane PI(1.0f, 1.0f, 1.0f, -1.0);
+	GLine l(GPoint3(0.0f, 0.0f, 0.0f), GVector3(1.0f, 1.0f, 1.0f));
 
-	GPlane PI = PI1;
-	cout << PI.GetNormal() << endl;
+	GPoint3 p;
+
+	bool ret = intersect_line_plane(p, l, PI);
+
+	cout << p << endl;
 
 	return 0;
 }