[ " OpenSceneGraph 3.0. Beginner s Guide. open source i. OpenSceneGraph, one of the best 3D graphics engines

OpenSceneGraph

3.0

Beginner

s

Guide

Create

_{high-performance}

virtual

_{reality applications}

with

OpenSceneGraph,

one

of the

best

3D

graphics engines

Rui

_Wang

Xuelei

_Qian

Ti.i;H;:r.c.HE

1

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Table

of

Contents

Preface

1

Chapter

1:

The

_Journey

into

_{OpenSceneGraph}

7

A

_quick

overview of

_rendering

middleware 8

Scene

_graphs

8

The Birth and

_development

of OSG 9

Components

10

Why

OSG? 12

WhousesOSG? 13

Havea

_quick

taste 14

Timeforaction

-say "Hello World" OSG

style

14

Live in

_community

15

Summary

17

Chapter

2:

_Compilation

and

Installation

of

_{OpenSceneGraph}

₁₉

System requirements

20

Using

the installer 20

Timeforaction-

installing

OSG 21

Running

utilities 26

Timeforaction-

playing

with

osgviewer

26

Using

the

_project

wizard 29

Time foraction-

creating

yoursolution withoneclick 29

Prebuilts

_making

trouble? 30

Cross-platform building

31

Starting

CMake 31

Time for action

-running

CMake in GUI mode 32

Setting

up

options

35

Generating packages using

Visual Studio 37

Time for action-

building

with_aVisualStudiosolution 37

Table

_of

Contents

Time for action-

building

witha UNIX makefile 38

Configuring

environment variables 40

Summary

41

Chapter

3:

_Creating

Your First OSG

_Program

43

Constructing

yourown

projects

44

Time for action-

building

applications

with CMake 44

Using

a root node 46

Time for action-

improving

the "Hello World"

example

47

Understanding

memory

management

48

ref_ptr<>

and

Referenced

classes 48

Collecting garbage:

why

and how 50

Tracing

the

_managed

entities 52

Timefor action-

monitoring

counted

objects

52

Parsing

command-line

_arguments

55

Time for action-

reading

the model filename from the command line 55

Tracing

with the notifier 57

Redirecting

the notifier 57

Time for

_{action-saving}

the

_log

file 58

Summary

60

Chapter

4:

_{Building Geometry}

Models

61

How

_OpenGL

draws

objects

62

Geode and Drawable classes 62

Rendering

basic

_shapes

63

Time for action-

quickly creating simple objects

64

Storing

arraydata 66

Vertices andvertex

attributes

66

Specifying drawing

types 68

Time for action-

drawing

acolored

quad

68

Indexing primitives

72

Time for action-

drawing

an octahedron 73

Using

polygonal techniques

77

Time for action-

tessellating

a

polygon

78

Rereading geometry

attributes 81

Customizing

a

primitive

functor 82

Time for action-

collecting triangle

faces 82

Implementing

yourowndrawables 86

Using OpenGL drawing

calls 87

Time for action-

creating

the famous

OpenGL

teapot

87

Summary

91

Chapter

5:

_Managing

Scene

_Graph

93

The

Group

interface 94

Managing

parent nodes 94

Time for action-

adding

modelstothe_scene

graph

96

Traversing

thescene

graph

98

Transformation

nodes 99

Understanding

the matrix 100

The MatrixTransform class 101

Time for action

-performing

translations of child nodes 101

Switch nodes 104

Time foraction-

switching

between the normal and

damaged

Cessna 105

Level-of-detail

nodes 107

Time for action-

constructing

a LODCessna 108

Proxy

and

_paging

nodes 110

Time for action-

loading

a modelatruntime 110

Customizing

yourown NodeKits 112

Timefor action-

animating

the switch node 113

The visitor

_{design pattern}

116

Visiting

scene

_graph

structures 117

Time for action-

analyzing

theCessna structure 118

Summary

121

Chapter

6:

_Creating

Realistic

_Rendering

Effects

123

Encapsulating

the

OpenGL

statemachine 124

Attributes and modes 124

Time for action-

setting polygon

modes of different nodes 126

Inheriting

renderstates 128

Timefor action-

lighting

the

glider

ornot 129

Playing

with fixed-function effects 131

Time for action

-applying

simple fog

tomodels 134

Lights

and

_light

sources 136

Timefor action

-creating light

sourcesin thescene 137

The

_Image

class 140

The basis oftexture

mapping

141

Time for action-

loading

and

applying

2Dtextures 143

Handling rendering

order 146

Time for action-

achieving

the translucent effect 148

Understanding graphics

shaders 152

Using uniforms

153

Time for action-

implementing

a cartooncow 154

Table

_of

Contents

Time for action-

generating

_a Bezier_curve 158

Summary

162

Chapter

7:

_Viewing

the World

163

From worldto screen 164

The Camera class 165

Rendering

order

of

cameras 167

Timefor action-

creating

_anHUD _camera 168

Using

a

_single

viewer 170

Digging

into the simulation

_loop

170

Time for action

-customizing

the simulation

loop

172

Using

a

composite

viewer 175

Timefor action-

rendering

more scenes atonetime 176

Changing

global display settings

179

Time for action-

enabling global multisampling

180

Stereo visualization 182

Time for action-

rendering anaglyph

stereo _scenes 183

Rendering

totextures 184

Frame

_{buffer, pixel buffer,}

and FBO 185

Time

for

action-

drawing

aircraftson a loaded terrain 186

Summary

192

Chapter

8:

_Animating

Scene

_Objects

₁₉₃

Taking

referencesto

functions

193

List of callbacks ₁₉₄

Time foraction-

switching

nodes in the

update

traversal 195

Avoiding

conflicting

modifications 198

Time

for

action-

drawing

a

geometry

dynamically

199

Understanding

ease motions 203

Animating

the

transformation

nodes 205

Time for action-

making

_useof the animation

path

205

Changing

rendering

states 208

Time

for

_{action-fading}

in ₂₀₉

Playing

moviesontextures 214

Time for action-

rendering

_a

flashing spotlight

₂₁₅

Creating

complex

key-frame

animations 218

Channels and animation managers 220

Time for

action

-

managing

animation channels

221

Loading

and

_rendering

characters ₂₂₅

Time for action-

creating

and

driving

_a character

system

225

Summary

228

Chapter

9:

_Interacting

with Outside Elements

231

Variousevents 232

Handling

mouseand

_{keyboard inputs}

233

Time for action-

driving

the Cessna 234

Adding

customized events 239

Timeforaction-

creating

_{a user}timer 239

Picking objects

243

Intersection 243

Time for action-

clicking

and

selecting

geometries

245

Windows, graphics

contexts,

andcameras 249

The Traits class 250

Time for action-

configuring

the traits of_a

rendering

window 251

Integrating

OSG intoawindow 254

Time for action-

attaching

OSGwith

awindow handlein Win32 255

Summary

260

Chapter

10:

_Saving

and

_Loading

Files 263

Understanding file

I/O plugins

264

Discovery

of

specified

extension 265

Supported

file formats 266

The

_{pseudo-loader}

270

Timeforaction-

reading

files fromthe Internet 271

Configuring third-party dependencies

272

Time for action-

adding

libcurl

support

for OSG 273

Writing

yourown

plugins

276

Handling

the datastream 278

Timefor action-

designing

and

parsing

a newfile format 279

Serializing

OSG nativescenes 283

Creating serializers

284

Time for action-

creating

serializers for user-defined classes 285

Summary

289

Chapter

11:

_Developing

Visual

_Components

291

Creating

billboardsina scene 292

Time for action-

creating

banners

facing

_you 292

Creating

texts 296

Time for action

-writing

descriptions

for the Cessna 297

Creating

3D texts 300

Timeforaction-

creating

texts in the world space 301

Creating

particle

animations 303

Table

_of

Contents

Time for action-

receiving

and

casting

shadows 311

Implementing special

effects

315

Time

for action-

drawing

the outline of models 316

Playing

withmoreNodeKits 318

Summary

319

Chapter

12:

_{Improving Rendering Efficiency}

321

OpenThreads

basics 322

Time

for

action-

using

a

separate

data receiver thread 322

Understanding

multithreaded

_rendering

328

Time for action-

switching

between different

threading

models 328

Dynamic

scene

_culling

335

Occluders and occludees 336

Time

for

action-

adding

occludersto a

complex

_scene 337

Improving

your

application

341

Time for action-

sharing

textureswithacustomized callback 343

Paging huge

scenedata 347

Making

use of the

quad-tree

348

Time foraction-

building

_a

quad-tree

for massive

rendering

348

Summary

357

Appendix:

Pop

Quiz

Answers

_{35_9_}

Chapter

2 359

Dependencies

of

_osgviewer

359

The difference between

_{ALL_BUILD}

and 'build all' 359

Chapter

3 360

Configuring

OSG

_{path options yourselves}

360

Releaseasmart

_pointer

360

Chapter

4 360

Results of different

_{primitive types}

360

Optimizing

indexed

_geometries

360

Chapter

5 361

Fast

_{dynamic casting}

₃₆₁

Matrix

multiplications

361

Chapter

6 361

Lights

withoutsources 361

Replacements

of built-in uniforms ₃₆₁

Chapter

7 ₃₆₂

Changing

model positions

in the HUDcamera 362 Anotherway to

display

thesame scene in differentviews 362

Chapter

8 ₃₆₂

Choosing

the

_alpha

setter and the callback 363

Chapter

9 363

Handling

eventswithin nodes 363

Globaland node-related events 363

Chapter

10 363

Getting

rid of

_{pseudo-loaders}

363

Understanding

the inheritance relations 364

Chapter

11 364

Text

_positions

andthe

_projection

matrix 364

Chapter

12 364

Carefully blocking

threads 364