godot_voxel/CODE_GUIDELINES.md

Code guidelines

For the most part, follow Godot conventions.

Syntax

• Class and struct names PascalCase
• Constants, enums and macros CAPITAL_CASE
• Other names snake_case
• Globals prefixed with g_
• Parameters prefixed with p_, but not really enforced so far. Matters for big functions.
• Private and protected fields prefixed with _
• Some private functions start with _, either to mimic Godot API, or to signify it's a re-used function that performs no checks
• Enums prefixed by their name. Example: enum Type { TYPE_ONE, TYPE_TWO }
• Open braces at the end of line, close them next line
• Never omit braces
• Space between binary operators and control flow
• Indent with tabs
• Use Clang-format to automate most of these rules (the one included in Godot should do it)

C++ features

• Don't use auto unless the type is impossible to express or a horrible template (like STL ones). IDEs aren't granted (Github reviews and diffs)
• STL is ok if it measurably performs better than Godot alternatives.
• Initialize variables next to declaration

Error handling

• No exceptions
• Check invariants, fail early. Use CRASH_COND to make sure states are as expected even if they don't cause immediate harm.
• Crashes aren't nice to users, so in those cases use ERR_FAIL_COND macros for code that can recover from error

Performance

In performance-critical areas:

• Avoid allocations. Re-use memory either with ObjectPool, fixed-size arrays or use std::vector capacity.
• Avoid virtual, Ref<T>, String
• Don't resize PoolVectors or Vector<T>, or do it in one go if needed
• Careful about what is thread-safe and what isn't. Some major areas of this module work within threads.
• Reduce mutex locking to a minimum
• Use data structures that are fit to the most frequent use over time (will often be either array, vector or hash map)
• Consider statistics if their impact is negligible. It helps monitoring how well the module performs even in release builds.
• Profile your code, in release mode. The lightweight util/zprofiling.h can help but you are free to use your own technique.

Godot API

• Use the most direct APIs for the job. Especially, don't use nodes. See VisualServer and PhysicsServer.
• Always use Read and Write when modifying PoolVector.
• Only expose a function if it is safe to use and guaranteed to remain present for a while
• use memnew, memdelete, memalloc and memfree so memory usage is counted within Godot monitors