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

WebGL implementation


Now let's take a look at how we can implement vertex and normal transformations in WebGL. The following diagram shows the theory that we have learned so far and it shows the relationships between the steps in the theory and the implementation in WebGL.

In WebGL, the five transformations that we apply to object coordinates to obtain viewport coordinates are grouped in three matrices and one WebGL method:

  1. The Model-View matrix that groups the model and view transform in one single matrix. When we multiply our vertices by this matrix, we end up in view coordinates.

  2. The Normal matrix is obtained by inverting and transposing the Model-View matrix. This matrix is applied to normal vectors for lighting purposes.

  3. The Perspective matrix groups the projection transformation and the perspective division, and as a result, we end up in normalized device coordinates (NDC).

    Finally, we use the operation gl.viewport to map NDCs to viewport coordinates:

    gl.viewport(minX, minY, width, height...