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

Using multiple textures


Up to this point, we've been doing all of our rendering using a single texture at a time. As you've seen this can be a useful tool. But there are times where we may want to have multiple textures that contribute to a fragment to create more complex effects. For these cases, we can use the WebGL's ability to access multiple textures in a single draw call, otherwise known as multitexturing.

We've already brushed up against multitexturing earlier in a chapter, so let's go back and look at it again. When talking about exposing a texture to a shader as a sampler uniform we used the following code:

gl.activeTexture(gl.TEXTURE0);
gl.bindTexture(gl.TEXTURE_2D, texture);

The first line, gl.activeTexture, is the key to utilizing multitexturing. We use it to tell the WebGL state machine which texture we are going to be manipulating with, in subsequent texture functions. In this case, we passed gl.TEXTURE0, which means that any following texture calls (such as gl.bindTexture) will...