ENH: New book example IceCream

src/Cxx/VisualizationAlgorithms/IceCream.cxx

+#include <vtkActor.h>
+#include <vtkCamera.h>
+#include <vtkCone.h>
+#include <vtkContourFilter.h>
+#include <vtkImplicitBoolean.h>
+#include <vtkPlane.h>
+#include <vtkPolyDataMapper.h>
+#include <vtkProperty.h>
+#include <vtkRenderWindow.h>
+#include <vtkRenderWindowInteractor.h>
+#include <vtkRenderer.h>
+#include <vtkSampleFunction.h>
+#include <vtkSphere.h>
+
+#include <vtkNamedColors.h>
+
+int main (int, char *[])
+{
+// This example demonstrates how to use boolean combinations of implicit
+// functions to create a model of an ice cream cone.
+
+  vtkSmartPointer<vtkNamedColors> colors =
+    vtkSmartPointer<vtkNamedColors>::New();
+
+// Create implicit function primitives. These have been carefully placed to
+// give the effect that we want. We are going to use various combinations of
+// these functions to create the shape we want; for example, we use planes
+// intersected with a cone (which is infinite in extent) to get a finite
+// cone.
+//
+  vtkSmartPointer<vtkCone> cone =
+    vtkSmartPointer<vtkCone>::New();
+  cone->SetAngle(20);
+
+  vtkSmartPointer<vtkPlane> vertPlane =
+    vtkSmartPointer<vtkPlane>::New();
+  vertPlane->SetOrigin(.1, 0, 0);
+  vertPlane->SetNormal(-1, 0, 0);
+
+  vtkSmartPointer<vtkPlane> basePlane =
+    vtkSmartPointer<vtkPlane>::New();
+  basePlane->SetOrigin(1.2, 0, 0);
+  basePlane->SetNormal(1, 0, 0);
+
+  vtkSmartPointer<vtkSphere> iceCream =
+    vtkSmartPointer<vtkSphere>::New();
+  iceCream->SetCenter(1.333, 0, 0);
+  iceCream->SetRadius(0.5);
+
+  vtkSmartPointer<vtkSphere> bite =
+    vtkSmartPointer<vtkSphere>::New();
+  bite->SetCenter(1.5, 0, 0.5);
+  bite->SetRadius(0.25);
+
+// Combine primitives to build ice-cream cone. Clip the cone with planes.
+  vtkSmartPointer<vtkImplicitBoolean> theCone =
+    vtkSmartPointer<vtkImplicitBoolean>::New();
+  theCone->SetOperationTypeToIntersection();
+  theCone->AddFunction(cone);
+  theCone->AddFunction(vertPlane);
+  theCone->AddFunction(basePlane);
+
+// Take a bite out of the ice cream.
+  vtkSmartPointer<vtkImplicitBoolean> theCream =
+    vtkSmartPointer<vtkImplicitBoolean>::New();
+  theCream->SetOperationTypeToDifference();
+  theCream->AddFunction(iceCream);
+  theCream->AddFunction(bite);
+
+// The sample function generates a distance function from the
+// implicit function (which in this case is the cone). This is
+// then contoured to get a polygonal surface.
+//
+  vtkSmartPointer<vtkSampleFunction> theConeSample =
+    vtkSmartPointer<vtkSampleFunction>::New();
+  theConeSample->SetImplicitFunction(theCone);
+  theConeSample->SetModelBounds(-1, 1.5, -1.25, 1.25, -1.25, 1.25);
+  theConeSample->SetSampleDimensions(128, 128, 128);
+  theConeSample->ComputeNormalsOff();
+
+  vtkSmartPointer<vtkContourFilter> theConeSurface =
+    vtkSmartPointer<vtkContourFilter>::New();
+  theConeSurface->SetInputConnection(theConeSample->GetOutputPort());
+  theConeSurface->SetValue(0, 0.0);
+
+  vtkSmartPointer<vtkPolyDataMapper> coneMapper =
+    vtkSmartPointer<vtkPolyDataMapper>::New();
+  coneMapper->SetInputConnection(theConeSurface->GetOutputPort());
+  coneMapper->ScalarVisibilityOff();
+
+  vtkSmartPointer<vtkActor> coneActor =
+    vtkSmartPointer<vtkActor>::New();
+  coneActor->SetMapper(coneMapper);
+  coneActor->GetProperty()->SetColor(colors->GetColor3d("chocolate").GetData());
+
+// The same here for the ice cream.
+//
+  vtkSmartPointer<vtkSampleFunction> theCreamSample =
+    vtkSmartPointer<vtkSampleFunction>::New();
+  theCreamSample->SetImplicitFunction(theCream);
+  theCreamSample->SetModelBounds(0, 2.5, -1.25, 1.25, -1.25, 1.25);
+  theCreamSample->SetSampleDimensions(128, 128, 128);
+  theCreamSample->ComputeNormalsOff();
+
+  vtkSmartPointer<vtkContourFilter> theCreamSurface =
+    vtkSmartPointer<vtkContourFilter>::New();
+  theCreamSurface->SetInputConnection(theCreamSample->GetOutputPort());
+  theCreamSurface->SetValue(0, 0.0);
+
+  vtkSmartPointer<vtkPolyDataMapper> creamMapper =
+    vtkSmartPointer<vtkPolyDataMapper>::New();
+  creamMapper->SetInputConnection(theCreamSurface->GetOutputPort());
+  creamMapper->ScalarVisibilityOff();
+
+  vtkSmartPointer<vtkActor> creamActor =
+    vtkSmartPointer<vtkActor>::New();
+  creamActor->SetMapper(creamMapper);
+  creamActor->GetProperty()->SetDiffuseColor(colors->GetColor3d("mint").GetData());
+  creamActor->GetProperty()->SetSpecular(.6);
+  creamActor->GetProperty()->SetSpecularPower(50);
+
+// Create the usual rendering stuff
+//
+  vtkSmartPointer<vtkRenderer> ren1 =
+    vtkSmartPointer<vtkRenderer>::New();
+
+  vtkSmartPointer<vtkRenderWindow> renWin =
+    vtkSmartPointer<vtkRenderWindow>::New();
+  renWin->AddRenderer(ren1);
+
+  vtkSmartPointer<vtkRenderWindowInteractor> iren =
+    vtkSmartPointer<vtkRenderWindowInteractor>::New();
+  iren->SetRenderWindow(renWin);
+
+// Add the actors to the renderer, set the background and size
+//
+  ren1->AddActor(coneActor);
+  ren1->AddActor(creamActor);
+  ren1->SetBackground(colors->GetColor3d("SlateGray").GetData());
+  renWin->SetSize(640, 480);
+  ren1->ResetCamera();
+  ren1->GetActiveCamera()->Roll(90);
+  ren1->GetActiveCamera()->Dolly(1.25);
+  ren1->ResetCameraClippingRange();
+  iren->Initialize();
+
+// render the image
+//
+  renWin->Render();
+  iren->Start();
+  return EXIT_SUCCESS;
+}

src/Cxx/VisualizationAlgorithms/IceCream.md

+### Description
+This example demonstrates how to use boolean combinations of implicit functions to create a model of an ice cream cone.
+