Book Image

WebGL Beginner's Guide

Book Image

WebGL Beginner's Guide

Overview of this book

WebGL is a new web technology that brings hardware-accelerated 3D graphics to the browser without installing additional software. As WebGL is based on OpenGL and brings in a new concept of 3D graphics programming to web development, it may seem unfamiliar to even experienced Web developers.Packed with many examples, this book shows how WebGL can be easy to learn despite its unfriendly appearance. Each chapter addresses one of the important aspects of 3D graphics programming and presents different alternatives for its implementation. The topics are always associated with exercises that will allow the reader to put the concepts to the test in an immediate manner.WebGL Beginner's Guide presents a clear road map to learning WebGL. Each chapter starts with a summary of the learning goals for the chapter, followed by a detailed description of each topic. The book offers example-rich, up-to-date introductions to a wide range of essential WebGL topics, including drawing, color, texture, transformations, framebuffers, light, surfaces, geometry, and more. With each chapter, you will "level up"ù your 3D graphics programming skills. This book will become your trustworthy companion filled with the information required to develop cool-looking 3D web applications with WebGL and JavaScript.
Table of Contents (18 chapters)
WebGL Beginner's Guide
Credits
About the Authors
Acknowledgement
About the Reviewers
www.PacktPub.com
Preface
Index

Use of color in objects


The final color of pixel is assigned in the fragment shader by setting the ESSL special variable gl_FragColor. If all the fragments in the object have the same color we can say that the object has a constant color. Otherwise, the object has a per-vertex color.

Constant coloring

To obtain a constant color we store the desired color in a uniform that is passed to the fragment shader. This uniform is usually called the object's diffuse material property. We can also combine object normals and light source information to obtain a Lambert coefficient. We can use the Lambert coefficient to proportionally change the reflecting color depending on the angle on which the light hits the object.

As shown in the following diagram, we lose depth perception when we do not use information about the normals to obtain a Lambert coefficient. Please notice that we are using a diffusive lighting model.

Usually constant coloring is indicated for objects that are going to become assets in a...