DEVELOPERS.md

Developers guidelines

In order to keep the API maintainable in the long term, we try to keep it as small as possible. This means the only public header of the project nodegl.h must be kept with as little symbols as possible.

DO

• DO Keep It Simple, Stupid
• DO follow the coding style you observe in the existing files
• DO atomic commits with the appropriate prefix (look at the git history)

DO NOT

• do NOT reorder public enum such as NGL_NODE_* as it breaks ABI
• do NOT insert a value in the middle of a public enum as it breaks ABI
• do NOT remove or change a public prototype as it breaks API and ABI
• do NOT add ANY external dependency without previous discussion
• do NOT use tabs (except in Makefile) and make sure not to add trailing whitespaces
• do NOT create ANY merge commit in the history, learn how to use git rebase
• do NOT add big (as in > 200kB) binary files to the repository

Nodes

The vast majority of the code is "node code", in files following the node_*.c pattern. Since nodes need to be able to introspect each others, all their respective "private" context are declared in a common (not publicly exposed) header nodes.h. This header also contains the structures definitions and prototypes required to implement a new node.

In order to add a node, you need to:

• in nodegl.h: declare a new NGL_NODE_* at THE END of the appropriate enum
• create a node_*.c file declaring a const struct node_class. Don't forget the Copyright header. See other node files, such as node_identity.c
• in nodes.c: declare the class you just create as extern
• in nodes.c: add a pointer to that class in node_class_map
• in Makefile: add the object name associated with your .c to LIB_OBJS
• run make updatespecs to update nodes.specs every time you update the parameter of the node
• refer to nodes.h for the available callbacks to implement in your class map