feat: mesh area and volumn std

- used to compare with integrating results

application/main.cpp

@@ -3,6 +3,7 @@
 
 
 #include <solve.h>
+#include <mesh_algorithm.hpp>
 
 #include <fstream>
 #include <string>
@@ -46,7 +47,7 @@ int main()
     auto runtime_blobtree = create_blobtree();
     auto node_iter1       = blobtree_add_primitive_node(runtime_blobtree, cylinder);
     auto node_iter2       = blobtree_add_primitive_node(runtime_blobtree, sphere1);
-    auto node_iter3       = blobtree_add_operation_node(runtime_blobtree, node_iter1, node_iter2, INTERSECTION_OP);
+    auto node_iter3       = blobtree_add_operation_node(runtime_blobtree, node_iter1, node_iter2, UNION_OP);
     auto baked_blobtree   = bake_blobtree(runtime_blobtree);
     destroy_blobtree(runtime_blobtree);
 
@@ -60,6 +61,11 @@ int main()
 
     auto result = generate_polymesh(solver);
     write_obj(result.mesh, "output.obj");
+    double area = compute_surface_area(&result.mesh);
+    double volume = compute_volume(&result.mesh);
+
+    std::cout << "area: " << area << std::endl;  // expected: 6
+    std::cout << "volume: " << volume << std::endl;  // expected: 1
     print_statistics(solver);
 
     destroy_solver(solver);