improved "ray_intersection_angle" functions.

inc/hgl/math/Vector.h

@@ -262,11 +262,40 @@ namespace hgl
         return length_squared(v1,v2)<=(gap*gap);
     }
 
-    inline float ray_angle_cos(const Vector3f &ray_dir, const Vector3f &ray_pos, const Vector3f &pos)
+    /**
+    * 计算射线与点的夹角(cos)
+    */
+    inline float ray_intersection_angle_cos(const Vector3f &ray_dir, const Vector3f &ray_pos, const Vector3f &pos)
     {
         return dot(ray_dir, normalized(pos - ray_pos));
     }
 
+    /**
+    * 计算射线与点的夹角(弧度)
+    */
+    inline float ray_intersection_angle_radian(const Vector3f &ray_dir, const Vector3f &ray_pos, const Vector3f &pos)
+    {
+        double val=dot(ray_dir, normalized(pos - ray_pos));
+
+        if(val>1)return 0;
+        if(val<-1)return HGL_PI;
+    
+        return acos(val);
+    }
+
+    /**
+     * 计算射线与点的夹角(角度)
+     */
+    inline float ray_intersection_angle_degree(const Vector3f &ray_dir, const Vector3f &ray_pos, const Vector3f &pos)
+    {
+        double val=dot(ray_dir, normalized(pos - ray_pos));
+
+        if(val>1)return 0;
+        if(val<-1)return 180;
+    
+        return rad2deg(acos(val));
+    }
+
     /**
     * 做一个2D旋转计算
     * @param result 结果