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

Time for action – enquiring on the state of buffers


Follow the given steps:

  1. Open the file ch2_StateMachine.html in the HTML5 browser of your preference.

  2. Scroll down to the initBuffers method. You will see something similar to the following screenshot:

  3. Pay attention to how we use the methods discussed in this section to retrieve and display information about the current state of the buffers.

  4. The information queried by the initBuffer function is shown at the bottom portion of the web page using updateInfo (if you look closely at runWebGLApp code you will see that updateInfo is called right after calling initBuffers).

  5. At the bottom of the web page (scroll down the web page if necessary), you will see the following result:

  6. Now, open the same file (ch2_StateMachine.html) in a text editor.

  7. Cut the line:

    gl.bindBuffer(gl.ARRAY_BUFFER,null);

    and paste it right before the line:

    coneIndexBuffer = gl.createBuffer();
  8. What happens when you launch the page in your browser again?

  9. Why do you think this behavior occurs...