The instance of vtkImporter contains vtkRenderWindow and vtkRenderer objects. It supports to recover original scene including lights, cameras, actors, etc. Here is a simple example which imports 3D studio file and shows the whole scene. import vtk DataRoot = “/Users/weiyang/Downloads/VTKData” importer = vtk.vtk3DSImporter() importer.ComputeNormalsOn() importer.SetFileName( DataRoot + “/Data/iflamigm.3ds” ) importer.Read() Read more…
We often need to delete some elements in an STL set. But it causes a strange bug if we are careless sometimes. One newbie in C Plus Plus program language may write the following code to delete all odd numbers in a set. int main() { vector<int> vec{ 1, 3, Read more…
Let’s do a simple experiment, to check the Internet connection between the user’s computer and a set of IPs by a shell script. The basic command tool is Ping which sends packets to network hosts. It will receive a network response in a short time if the Internet connection is Read more…
I want to get the solution of the equation Bisection Method The first algorithm for the problem is bisection method. The algorithm bisection method doesn’t require derivation for the equation. It just needs a possible solution range [l, r], then calculates the variable mid as , compares the result of Read more…
Driven class of unary_function can be used to check a single element based on special condition.Programmer can regard it as some algorithms’ parameter, such as count_if, find_if, and find_if_not.The following code shows how to write a customized unray class and use it. C++ struct Widget { int GetSpeed() const { return speed; } Widget( const Read more…
We need not sort all elements sometimes. Here are a few simple examples of STL algorithms partial_sort, nth_element, and partition. partial_sort For example, find the 5 biggest ones in 10 random numbers. #include <iostream> #include <vector> #include <cstdlib> #include <ctime> #include <algorithm> using namespace std; int main() { vector<int> values; Read more…
We need a flexible compare way for our objects in some situations, so it’s necessary to write our own compare class. The article has an example which puts all widgets in a multiset container, the widgets should be sort by its data member Speed. The widgets are created with random Read more…
vtkReverseSense can help us to reverse the direction of point normals and cell normals. The following code shows a simple example which display vertexes’ normals by cones in a sphere. Here is its original geometric states. #include <iostream> #include <vtkSmartPointer.h> #include <vtkSphereSource.h> #include <vtkActor.h> #include <vtkConeSource.h> #include <vtkRenderer.h> #include <vtkRenderWindow.h> Read more…
Draw geometric curve of Quadratic equation Here is a simple quadratic equation: Draw its geometric curve by wolfram. We can use Table to calculate all discrete values in special range. Table[2*x^2 + 1, {x, -10, 10}] {201, 163, 129, 99, 73, 51, 33, 19, 9, 3, 1, 3, Read more…