Coin3d--Getting Started

//----------------------------------------------------
//    Remember (in our first homework) where those "include" files reside??
//-----------------------------------------------------
//
//Using Inventor Xt window
//
#include <Inventor/Xt/SoXt.h>
#include <Inventor/Xt/SoXtRenderArea.h>
//
//Using Inventor "nodes".
// Inventor "node" is the basic element of a scene graph: data methods that define some specific 3D shape, property, or grouping.
//Here, we have:
//           Shape node: a cone by "SoCone"
//          Property nodes: a light source by "SoDirectionLight"
//                                    material definition by "SoMaterial" (of ambient color, diffuse color, shininess... on the material surface)
//                                    a camera by "SoPerspectiveCamera"
//          Gouping node: "SoSeparator"---Please remember this node name--"SoSeparator", which is widely used in Inventor animation programing.
//
#include <Inventor/nodes/SoCone.h>
#include <Inventor/nodes/SoDirectionalLight.h>
#include <Inventor/nodes/SoMaterial.h>
#include <Inventor/nodes/SoPerspectiveCamera.h>
#include <Inventor/nodes/SoSeparator.h>

//Please note, "Xxxx.h" file gives a class "Xxxx"
//
main(int , char **argv)
{
// Initialize Inventor. This returns a main window to use.
// If unsuccessful, exit.
Widget myWindow = SoXt::init(argv[0]); // pass the app name
if (myWindow == NULL) exit(1);

// Make a scene containing a red cone
//From now on, keep in mind that a scene (graph) is but a data structure.
//When you are going to create a scene, you know how many objects (data set) in the scene, the relationship (distance, or moving speed) among those objects, the material properties attach to every object, and so on. Therefore, those objects and their properties are logically connected with each other with a TREE STRUCTURE.
//There is ORDER in the tree structure when you adding "child" nodes to their father, though it doesn't matter with property "nodes" belonging to same object (shape node).

//Our job is to create such a data tree structure of a scene graph, here, a simple red cone.

// Of course we should have a "root"
SoSeparator *root = new SoSeparator;

//Some child nodes:
SoPerspectiveCamera *myCamera = new SoPerspectiveCamera;
SoMaterial *myMaterial = new SoMaterial;

root->ref(); //VERY IMPORTANT!!!--------- "ref()"

//Add child nodes (properties), though order here is not important, it is a good practice to add them in certain order.
root->addChild(myCamera);
root->addChild(new SoDirectionalLight);
myMaterial->diffuseColor.setValue(1.0, 0.0, 0.0); // Red color
root->addChild(myMaterial);

//Add the shape object node
//IMPORTANT: this node should be added into root as the "LAST" one: all the above property node will not produce the effect unless they "meet" one real shape node.
root->addChild(new SoCone);

// Create a renderArea in which to see our scene graph.
// The render area will appear within the main window---"myWindow".
SoXtRenderArea *myRenderArea = new SoXtRenderArea(myWindow);

// Make myCamera see everything.
myCamera->viewAll(root, myRenderArea->getViewportRegion());

// Put our scene in myRenderArea, change the title
myRenderArea->setSceneGraph(root);
myRenderArea->setTitle("Hello Cone");
myRenderArea->show();

SoXt::show(myWindow); // Display main window
SoXt::mainLoop(); // Main Inventor event loop
}

References:

News Group and Mailing List:

How to Use the References

Open Inventor Sampler (based on Ref. 1 above)

First Example: A Red Cone

Second Example: Using Engines to Make the Cone Spin

Third Example: Adding a Trackball Manipulator

Fourth Example: Adding the Examiner View

Homework 2: