Brad E. Hollister - Core Blender Development: Understanding the Essential Source Code

The goal of this chapter is to familiarize you with the Blender core source , and is intended to be the starting point for the rest of the book. Blenders codebase is written primarily in the C programming language. Part of this introduction is a preliminary discussion of Blenders CMake build system. Additionally, we provide an execution trace of how Blender registers an operator, and of the execution of its callback. Much of this book will be easier to digest, if you make an effort to browse the source code in a text editorideally, after reading the associated passage. If you have not yet downloaded and compiled the Blender source code, you will eventually want to do so. However, this chapter may be read first.

Throughout this book, we do not want to merely replicate the wealth of information already present at https://developer.blender.org . Nonetheless, we direct your attention to these valuable resources at the appropriate times. You should use those external documents in support of, and in tandem with, the material of this text.

Such experience could otherwise only be gained by direct inspection (and significant experimentation) of the source code. Ultimately, as you progress, that approach will be necessary as well.

The official developer site is available at ). There you will find the Blender Foundations Phabricator site, responsible for being a portal to their code repositories, bug tracker, developer documents, etc.

Figure 1-1

The Blender Foundations portal for developers: https://developer.blender.org

As aspects can change concerning how to clone and build Blender, and building is both platform specific and configurable, the best way to obtain up-to-date instructions is to visit https://developer.blender.org .

Communication Channels

It is helpful to speak with developers actively working on the core source code. While the Blender developer community maintains an Internet Relay Chat (IRC) room, located on Freenode in the channel #blendercoders, the latest way to interact in real-time is on ).

Figure 1-2

Blenders browser-based chat server interface

As with most open source projects, Blender has an email list. This provides another key resource for communication with the Blender developer community. To post a message for core developers to read, and potentially answer, the email address is bf-committers@blender.org (see Figure ). This is the appropriate list for developers (and, hopefully, eventually committers), as there are other mailing lists dedicated only to users, and other aspects of the Blender project apart from development.

Figure 1-3

Bf-committers subscription web page. This sign-up page is accessible from the official Blender project wiki

The Blender Source Tree

To begin, you should become familiar with three essential documents . These are

• https://wiki.blender.org/wiki/Reference/FAQ , which is unfortunately not found in the source distribution itself. It contains information on what Blender DNA and RNA are, along with the datatoc