Units Map | Manual | Castle Game Engine

Units Map

Table of Contents

1. Introduction
2. Dependencies
3. Unit groups

1. Introduction

Castle Game Engine includes a lot of units. They are divided into groups, which correspond to the subdirectories in the engine src subdirectory: transform, audio and so on. The groups are shortly described below.

2. Dependencies

One of the ways how we keep the engine maintainable is to limit the dependencies between unit groups. For example, the transformation and UI stuff depends on images, but the units in the images group cannot depend on units in the transform or ui groups. A simple dependency tree allows to easily debug some hard problems (when you want to strip the used units, to get to the "bottom of the problem").

The allowed dependencies are listed below. In short, the list of subdirectories goes from "lower level" to "higher level" in the sections below.

These dependencies are automatically checked (by tools/internal/check_units_dependencies, executed by Jenkins after every push).

Note

Temporarily, some units are allowed exception to break from this rule. Right now 3 units have such exception, i.e. they actually break dependencies outlined below. See AllowedExceptions list in check_units_dependencies. This is a TODO — we will fix those. It’s also a practical decision — while we want to watch over these dependencies, in practice breakage (in some cases) has no bad consequences.

3. Unit groups

3.1. castle_base package

3.1.1. base

Basic utilities and classes. Stuff for dealing with vectors, colors, strings, Unicode, logging, rectangles…

Depends on: nothing else.

3.1.2. files

Files, URLs, XML utilities, downloading files from the network. See manual about network and downloading.

Depends on: everything above (that is, units in "base" group).

3.1.3. audio

Sound files loading, sound playback (including 3D sound), processing of sound files. See manual about sound.

Depends on: everything above (that is, units in "base" and "files" groups).

3.1.4. images

Image loading and saving: TCastleImage, TGPUCompressedImage (with ancestor TEncodedImage).

Depends on: everything above except audio.

3.1.5. base_rendering

OpenGL(ES) basic units. Headers, loading images/textures to OpenGL(ES), rendering basic 2D primitives (TDrawableImage, DrawPrimitive2D).

Depends on: everything above except audio.

3.1.6. fonts

Loading font data from files using FreeType, rendering text (TCastleFont), converting font data to be embeddable as Pascal units.

Depends on: everything above except audio.

3.1.7. ui

2D user interface of the engine: TCastleContainer, TCastleUserInterface, lots of TCastleUserInterface descendants like buttons, rectangles, labels… Also keyboard, mouse and other input handling.