Added Area.h

inc/hgl/math/Area.h

@@ -0,0 +1,70 @@
+#pragma once
+
+#include<hgl/math/Vector.h>
+
+namespace hgl
+{
+    /*
+    * 根据三角形的三边长计算三角形的面积
+    */
+    inline const float TriangleArea(const float a,const float b,const float c)
+    {
+        const float s=(a+b+c)*0.5f;
+
+        return sqrt(s*(s-a)*(s-b)*(s-c));
+    }
+
+    inline const float TriangleArea(const Vector2f &a,const Vector2f &b,const Vector2f &c)
+    {
+        return fabs((a.x-c.x)*(b.y-c.y)-(a.y-c.y)*(b.x-c.x))*0.5f;
+    }
+
+    inline const float TriangleArea(const Vector3f &a,const Vector3f &b,const Vector3f &c)
+    {
+        return glm::length(glm::cross(b-a,c-a))*0.5f;
+    }
+
+    inline const float RectangleArea(const float width,const float height)
+    {
+        return width*height;
+    }
+
+    inline const float RectangleArea(const Vector2f &size)
+    {
+        return size.x*size.y;
+    }
+    
+    /**
+     * 正圆面积计算
+     * @param radius 半径
+     */
+    inline const float CircleArea(const float radius)
+    {
+        return HGL_PI*radius*radius;
+    }
+    
+    /**
+     * 椭圆面积计算
+     * @param l_radius 长半径
+     * @param s_radius 短半径
+     */
+    inline const float EllipseArea(const float horizontal_radius,const float vertical_radius)
+    {
+        return HGL_PI*horizontal_radius*vertical_radius;
+    }
+
+    inline const float EllipseArea(const Vector2f &radius)
+    {
+        return HGL_PI*radius.x*radius.y;
+    }
+
+    inline const float SectorArea(const float radius,const float angle)
+    {
+        return HGL_PI*radius*radius*angle/360.0f;
+    }
+
+    inline const float QuadArea(const Vector3f &a,const Vector3f &b,const Vector3f &c,const Vector3f &d)
+    {
+        return TriangleArea(a,b,c)+TriangleArea(a,c,d);
+    }
+}//namespace hgl