98 lines
7.8 KiB
HTML
98 lines
7.8 KiB
HTML
<!doctype html>
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<html>
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<title>Townengine Wiki : About Townengine</title>
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<link rel="stylesheet" href="style.css">
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</head>
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<body>
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<h1 style="margin-bottom:0in">T1. About Townengine<span style="float:right">{twn}</h1>
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<a href="index.html">Go back
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<p><a name="introduction"></a><strong>T1.1 </strong><strong>Introduction</strong>
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<blockquote>
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<p>Townengine, {twn}, is an opinionated game development framework designed around specific set of ideas:
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<p><b>Simplicity.</b> It makes assumptions that trickle down to your game code. There's no delta between frames, nor resolution change.
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Textures have constant known size, not requiring scaling.
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<p><b>Managed state.</b> Designed around this we can provide hot reloading at any point,
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serialization for save files and debug dumps, as well as synchronization over network, without any user code.
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Every frame apparent engine state is cleared, which removes another variable for you to handle, - when to initialize.
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There's no need for you to call `LoadImage()` of sorts before using it in render, you just pass filepaths around.
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Input is initialized anew each frame, making rebinds trivial.
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<p><b>Device care.</b> Older hardware is still used in many parts of the world,
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which users might not otherwise be able to make games they dream of.
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Restrictions also constitute in desired aesthetics. Graphics capabilities are limited, but
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what is present, - is heavily optimized. It is rather different from performance-driven approach that tries to take
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advantage of the latest hardware and features, sacrificing both the reach and portability in process.
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<p><b>Portability.</b> Written in C11 with all dependencies being in C, it's possible to compile it to most platforms.
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SDL2 is at the center and you cannot get better than this. Default graphics API is OpenGL 1.5 with extension detection.
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As an example, it builds and runs on Haiku OS with LLVMpipe.
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<p><b>Language agnosticism.</b> API is restricted to minimize the amount of glue code.
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Language interpreters don't need to be part of the engine itself. Anything with C ABI support can link to it.
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/share/twn_api.json schema is provided for automatic binding and annotation generation.
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<p><b>Use-case orientation.</b> It doesn't try to be a yet another general purpose engine conquering all and nothing.
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Instead we seek particular use cases and implement the most essential parts.
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User code copying should be promoted instead of delegating it all to the engine, this way we don't restrict.
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<p><b>Iterability.</b> Defaults provided for most of the API, making initial code faster to spring.
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Hot reloading works for both assets and code.
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<p><b>Low latency.</b> Care is given to various incarnations of feared latency. Engine is fast to build, allowing for low commitment local patches.
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Startup time is profiled and frequently looked into. Streaming is used as much as possible.
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<p><b>No-Versioning.</b> We don't stick to releases and "contract" obligations for things to remain stagnant.
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It's fair to ask end user to put little effort if they need newer set of features, instead of putting all the burden on us.
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You can always just stick to particular version you started the development of the project with,
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{twn} doesn't need system wide installation.
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<p><b>Bounded.</b> Most places assume runtime limits, to help with portability and growing out-of-hand complexity.
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Frames cannot take more than sane allocated time, breaking off infinite loops.
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<p><b>Toolable.</b> External editors are the way, with their own separate modes of being. Simple web socket interface will be defined for that.
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</blockquote>
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<p><a name="wiki"></a><strong>T1.2 </strong><strong>Wiki</strong>
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<blockquote>
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<p>Purpose of this wiki is to collect information on various usages of {twn} across the genres, FAQ style.
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You're welcomed to contribute to it. It's written in HTML so basic you can edit it by hand.
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Just check <a href="template.html">template.html</a>.
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<p>Content is divided into chapters, where prefix specifies its category. Currently following prefixes are used:
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<ul>
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<li><b>T</b> for townengine; development and apis.
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<li><b>G</b> for gamedev; guides and FAQs on game making.
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</ul>
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<p>There's no reason not to pile up knowledge, refactoring is irrelevant.
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</blockquote>
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<p><a name="abi"></a><strong>T1.3 </strong><strong>Procedure Interface</strong>
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<blockquote>
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<p>For native code ABI defines convention to ease tooling integration. Platform/compiler C ABI is assumed,
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but it should be trivially expressible in JSON-RPC as well.
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<ul>
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<li>32 bit floating point is the only numeric type.
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<li>Procedure parameters can only use basic types, with no aggregates. Exceptions are Vec, Rect and Color types.
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(see /include/twn_types.h)
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<li>Enum types are allowed, but must be converted to floats. Identity strings are preferred.
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<li>No opaque nor pointer types allowed, use string keys if needed. Think of it as data base relations.
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<li>Only null terminated string is allowed as a sequential type in both parameters and returns.
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<li>Return value could be a simple aggregate that is translatable to a dictionary of primitives, without nesting.
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<li>Symbols should not contain numerics. For example, sqrt2 must become square_root.
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<li>/share/twn_api.json file is hand-kept with a schema to aid automatic binding generation and tooling.
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<li>Parameter names should not collide with keywords of any language that is targeted; if so happens, parameter alias could be added.
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Currently forbidden: <b>repeat</b>.
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<li>Procedure can't have more than 8 parameters.
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<li>Decimal portions of floating points are lossy both due to rounding errors and text representation,
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thus they cannot be relied to hold for equality. Integer parts of floats are good up to 2^24.
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<li>Returns must be restricted/closed on being constant over frame, parameters or asset frame.
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</ul>
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</blockquote>
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<p><a name="dev-on"></a><strong>T1.4 </strong><strong>Developing</strong>
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<blockquote>
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<p>One of hard choices we employ is requirement on having more or less the same tools on all platforms in order to compile.
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If you're on Windows you need to get a MinGW environment. [cmake] and [python3] (>specify versions<) are also required.
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[clang] is preferred over [gcc], as it has superior lto, which matters a great deal with our architecture (literal day and night difference in frame time).
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[git] is used for version control. Git for Windows distribution could also be used for getting conforming cli environment, much recommended.
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<p>Inside $TWNROOT/bin folder the [twn] script is used for engine instrumentation.
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It could build and run your projects and even open this very wiki locally!
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You could execute [source hooks] inside $TWNROOT to add [twn] to your $PATH temporarily. Symlinking of it is also supported.
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Look inside the script to see what it can do, it's ever growing !
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<p>[twn init <template> <name>] could be used to quickly initialize a project.
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Look into $TWNROOT/apps/templates folder to see available templates.
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<p>Support for [clangd] completions is provided with [twn devcompl] command, it generates compile_commands.json inside $TWNROOT/build folder.
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Having workspace placed in $TWNROOT by your IDE should be enough to make it all work. Rerun [twn devcompl] if new files are added.
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<p>Web target requires [emsdk] as of now. Use [twn build --target=web] to use it.
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</blockquote>
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</body>
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</html>
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