Fix surface area

exercise3/src/SurfaceArea.cpp

@@ -52,6 +52,26 @@ struct Triangles {
 		return points;
 	}
 
+	float calculate_h(OpenMesh::Vec3f& vector, OpenMesh::Vec3f& p) {
+		float x = vector[0];
+		float y = vector[1];
+		float z = vector[2];
+
+		float x1 = p[0];
+		float y1 = p[1];
+		float z1 = p[2];
+
+		float r = - ( (-x*x1 - y*y1 - z*z1) / (x*x + y*y + z*z) );
+
+		OpenMesh::Vec3f s_vec(r * vector);
+
+		OpenMesh::Vec3f h_vec = s_vec - p;
+
+		float h = h_vec.length();
+
+		return h;
+	}
+
 	float surface_area() {
 		float surface_area = 0.0f;
 
@@ -60,24 +80,12 @@ struct Triangles {
 			OpenMesh::Vec3f p2 = triangle.points[1];
 			OpenMesh::Vec3f p3 = triangle.points[2];
 
-			/*
+			OpenMesh::Vec3f p12_vec = p1 - p2;
+			OpenMesh::Vec3f p23_vec = p1 - p3;
 
-						3
+			OpenMesh::Vec3f cross = OpenMesh::cross(p12_vec, p23_vec);
-					  /	|  \
-				    /	|h   \
-				  /		|	   \
-				1 -------------- 2
-						  g
 
-				surface area = (g * h) / 2;
+			surface_area += cross.length() / 2;
-			*/
-
-			OpenMesh::Vec3f g_vec = p1 - p2;
-			float g = g_vec.length();
-
-			float h = 0.0f;
-
-			surface_area += (g * h) / 2;
 		}
 
 		return surface_area;