172 lines
7.1 KiB
ReStructuredText
172 lines
7.1 KiB
ReStructuredText
Godot’s design philosophy
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=========================
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**Every game engine is different and fits different needs**. They do not
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only offer a wide range of features: each engine’s design is unique. This
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leads to different workflows and different ways to reason about your
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games’ structure. This all stems from their design philosophy.
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This page is here to **help you understand how Godot works**, starting
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from some of its core pillars. It is not a list of available features or
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an engine comparison. To know whether any engine can be a good fit for
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your project or not, you need to both try it out for yourself and
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understand its design and limitations.
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Object-oriented design and composition
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--------------------------------------
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Godot embraces object-oriented design at its core with its **flexible
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scene system and Node hierarchy**. It tries to stay away from strict
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programming patterns to offer an intuitive way to structure your game.
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For one, Godot lets you **compose or aggregate** scenes.
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It's like nested prefabs: you can create a BlinkingLight scene and
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a BrokenLantern scene that uses the BlinkingLight.
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Then, create a city filled with BrokenLanterns.
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Change the BlinkingLight's color, save, and all the
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BrokenLanterns in the city will update instantly.
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On top of that, you can **inherit** from any scene.
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A Godot scene could be a Weapon, a Character, an Item, a Door, a Level,
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part of a level… anything you’d like. It works like a class in pure code
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except you’re free to design it using the editor, using only the
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code, or mixing and matching the two.
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It’s different from prefabs you find in several 3d engines as you can
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then inherit from and extend those scenes. You may create a Magician
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that extends your Character. Modify the Character in the editor and the Magician
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will update as well. It helps you build your projects so that their
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structure matches the game’s design.
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|image0|
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Also note that Godot offers many different types of objects called
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nodes, each with a specific purpose. Nodes are part of a tree and always
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inherit from their parents up to the Node class. Although the engine
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does feature some components like collision shapes, they’re the
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exception, not the norm.
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|image1|
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Sprite is a Node2D, a CanvasItem and a Node. It has all the properties
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and features of its three parent classes, like transforms or the ability
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to draw custom shapes and render with a custom shader.
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All-inclusive package
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---------------------
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Godot tries to provide its own tools to answer all of the most common
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needs. It has a dedicated scripting workspace, an animation editor, a
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tilemap editor, a shader editor, a debugger, a profiler,
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hot-reload locally and on remote devices, etc.
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|image2|
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The goal is to offer a full package to create games and a continuous
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user experience. You can still work with external programs as long as
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there is an import plugin for it or you can create one, like the `Tiled
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map editor importer <https://github.com/vnen/godot-tiled-importer>`__.
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That is also partly why Godot offers its own programming languages
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GDscript and VisualScript, along with C#. They’re designed for the needs
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of game developers, game designers, and they’re tightly integrated in
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the engine and the editor.
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GDscript lets you write simple code using a Python-like syntax,
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yet it detects types and offers a static-language's quality of auto-completion.
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It's also optimized for gameplay code with built-in types like Vectors, Colors, etc.
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Note that with GDNative, you can write high performance code using compiled
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languages like C, C++, Rust or Python (Cython compiler) without recompiling
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the engine.
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|image3|
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*VisualScript is a node-based programming language that integrates well
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in the editor. You can drag and drop nodes or resources into the graph
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to create new code blocks.*
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Note that if this is true for 2d at the time of writing, the 3d
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workspace still doesn’t feature as many tools. You’ll need external
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programs or add-ons to edit terrains, animate complex characters, etc.
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Godot provides a complete API to extend the editor’s functionality using
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game code. See `The Godot editor is a Godot game <#>`__ below.
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|image4|
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*A State Machine editor plugin in Godot 2 by kubecz3k. It lets you
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manage states and transitions visually*
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Open source
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-----------
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Godot offers a fully open source code-base under the MIT license. This
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means all the technologies that ship with it have to be Free as well.
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For the most part, they’re coded from the ground up by contributors.
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Anyone can plug in proprietary tools for the needs of their projects.
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They just won’t ship with the engine. This may include NViDia PhysX,
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Google Admob or an FBX file importer. Any of these can come as
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third-party plugins instead.
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On the other hand, an open codebase means you can learn from and extend
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the engine to your heart’s content. You can also debug games easily
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as Godot will print errors with a stack trace, even if they come from the engine itself.
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Note this does not affect the work you do with Godot in any way: there’s
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no strings attached to the engine or anything you make with it.
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Community-driven
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----------------
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**Godot is made by its community, for the community and all game
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creators out there**. It’s the needs of the users and open discussions
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that drive the core updates. New features from the core developers often
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focus on what will benefit the most users first.
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That said, although a handful of core developers work on it full-time,
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the project has over 500 contributors at the time of writing. Benevolent
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programmers work on features they may need themselves so you’ll see
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improvements in all corners of the engine at the same time in every
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major release.
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The Godot editor is a Godot game
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--------------------------------
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The Godot editor runs on the game engine. It uses the engine’s own UI
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system, it can hot reload code and scenes when you test your projects,
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or run game code in the editor. This means you can **use the same code**
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and scenes for your games or **to build plugins and extend the editor**.
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This leads to a reliable and flexible UI system as it powers the editor
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itself. With the ``tool`` keyword, you can run any game code in the editor.
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|image5|
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*RPG in a Box is a voxel RPG editor made in Godot 2. It uses Godot’s UI
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tools for its node-based programming system and for the rest of the
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interface.*
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Put the ``tool`` keyword at the top of any GDscript file and it will run
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in the editor. This lets you create plugins like custom level editors,
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import and export plugins or scripts with the same nodes and API you use
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in your projects.
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Separate 2d and 3d engines
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--------------------------
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Godot offers dedicated 2d and 3d rendering engines. As a result **the
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base unit for 2d scenes is pixels**. Even though the engines are
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separate, you can render 2d in 3d, 3d in 2d, and overlay 2d sprites and
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interface over your 3d world.
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.. |image0| image:: ./img/engine_design_01.png
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.. |image1| image:: ./img/engine_design_02.png
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.. |image2| image:: ./img/engine_design_03.png
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.. |image3| image:: ./img/engine_design_visual_script.png
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.. |image4| image:: ./img/engine_design_fsm_plugin.png
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.. |image5| image:: ./img/engine_design_rpg_in_a_box.png
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