Book Image

OpenSceneGraph 3 Cookbook

By : Rui Wang, Xuelei Qian
Book Image

OpenSceneGraph 3 Cookbook

By: Rui Wang, Xuelei Qian

Overview of this book

<p>OpenSceneGraph is an open source 3D graphics application programming interface, used by application developers in fields such as visual simulation, computer games, virtual reality, scientific visualization, and modeling. Familiar with its concepts and APIs, and need to improve your knowledge? This book is here to help. With exactly 100 recipes, it will enrich your experience and take you to the next level.<br /><br /><em>OpenSceneGraph 3 Cookbook</em> will escort you into the world of real-time 3D development with OpenSceneGraph, the world famous 3D graphics engine. The book assumes that you are already familiar with some basic concepts, and provides 100 vivid recipes to demonstrate how to utilize the API flexibly and how to implement some practical aspects.<br /><br />The book is divided into 10 chapters, each of which focuses on one topic. Readers may start from any topic they are interested in.<br /><br />The book includes customizing OpenSceneGraph, designing scene graph, geometry, scene navigation, animations, effects using fixed pipeline and shaders, managing mass data, and miscellaneous discussions. Every recipe will prove to be useful in a practical way or in research.<br /><br /><em>OpenSceneGraph 3 Cookbook</em> gives you a wide insight about 3D programming using OpenSceneGraph, with a set of meaningful and interesting examples.</p>

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OpenSceneGraph 3 Cookbook
Rui Wang | Xuelei Qian
Mar, 2012 | 426 pages
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Table of Contents (15 chapters)
OpenSceneGraph 3 Cookbook
OpenSceneGraph 3 Cookbook
Credits
Credits
About the Authors
About the Authors
About the Reviewers
About the Reviewers
www.PacktPub.com
www.PacktPub.com
Preface
Preface
Free Chapter
1
Customizing OpenSceneGraph
Customizing OpenSceneGraph
Introduction
Checking out the latest version of OSG
Configuring CMake options
Building common plugins
Compiling and packaging OSG on different platforms
Compiling and using OSG on mobile devices
Compiling and using dynamic and static libraries
Generating the API documentation
Creating your own project using CMake
2
Designing the Scene Graph
Designing the Scene Graph
Introduction
Using smart and observer pointers
Sharing and cloning objects
Computing the world bounding box of any node
Creating a running car
Mirroring the scene graph
Designing a breadth-first node visitor
Implementing a background image node
Making your node always face the screen
Using draw callbacks to execute NVIDIA Cg functions
Implementing a compass node
3
Editing Geometry Models
Editing Geometry Models
Introduction
Creating a polygon with borderlines
Extruding a 2D shape to 3D
Drawing a NURBS surface
Drawing a dynamic clock on the screen
Drawing a ribbon following a model
Selecting and highlighting a model
Selecting a triangle face of the model
Selecting a point on the model
Using vertex-displacement mapping in shaders
Using the draw instanced extension
4
Manipulating the View
Manipulating the View
Introduction
Setting up views on multiple screens
Using slave cameras to simulate a power-wall
Using depth partition to display huge scenes
Implementing the radar map
Showing the top, front, and side views of a model
Manipulating the top, front, and side views
Following a moving model
Using manipulators to follow models
Designing a 2D camera manipulator
Manipulating the view with joysticks
5
Animating Everything
Animating Everything
Introduction
Opening and closing doors
Playing a movie in the 3D world
Designing scrolling text
Implementing morph geometry
Fading in and out
Animating a flight on fire
Dynamically lighting within shaders
Creating a simple Galaxian game
Building a skeleton system
Skinning a customized mesh
Letting the physics engine be
6
Designing Creative Effects
Designing Creative Effects
Introduction
Using the bump mapping technique
Simulating the view-dependent shadow
Implementing transparency with multiple passes
Reading and displaying the depth buffer
Implementing the night vision effect
Implementing the depth-of-field effect
Designing a skybox with the cube map
Creating a simple water effect
Creating a piece of cloud
Customizing the state attribute
7
Visualizing the World
Visualizing the World
Introduction
Preparing the VirtualPlanetBuilder (VPB) tool
Generating a small terrain database
Generating terrain database on the earth
Working with multiple imagery and elevation data
Patching an existing terrain database with newer data
Building NVTT support for device-independent generation
Using SSH to implement cluster generation
Loading and rendering terrain from the Internet
8
Managing Massive Amounts of Data
Managing Massive Amounts of Data
Introduction
Merging geometry data
Compressing texture
Sharing scene objects
Configuring the database pager
Designing a simple culling strategy
Using occlusion query to cull objects
Managing scene objects with an octree algorithm
Rendering point cloud data with draw instancing
Speeding up the scene intersections
9
Integrating with GUI
Integrating with GUI
Introduction
Integrating OSG with Qt
Starting rendering loops in separate threads
Embedding Qt widgets into the scene
Embedding CEGUI elements into the scene
Using the osgWidget library
Using OSG components in GLUT
Running OSG examples on Android
Embedding OSG into web browsers
Designing the command buffer mechanism

Merging geometry data

It is common in a complex program to contain hundreds of thousands of geometry objects. For example, a digital city running on the local machine or the Internet may have 10,000 detailed houses, and each house can have doors, windows, fences, and many other components.

It may be sometimes confusing for developers in this situation—should we try to merge all (or majority) of them in to one osg::Geometry object or use more geometries to represent the different house elements? The answer depends on different situations that we may face. However, less geometry objects always perform better while rendering the same number of triangles, as the shown in the following section.

How to do it...

Let us start.

  1. 1. Include necessary headers:

    #include <osg/Geometry>
#include <osg/Group>
#include <osgDB/ReadFile>
#include <osgViewer/ViewerEventHandlers>
#include <osgViewer/Viewer>

  2. 2. We will try to show the importance of merging geometries, so the first thing...

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