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110 lines
5.1 KiB
Markdown
110 lines
5.1 KiB
Markdown
# raycastlib
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Public domain ray casting library for (not only) resource-limited computers.
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If you like this, you may also like my similar project: [small3dlib](https://gitlab.com/drummyfish/small3dlib). These two libraries can very easily be combined together -- here is a proof-of-concept gif (environment rendered with raycastlib, cubes with small3dlib):
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eye-candy previews
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------------------
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Pokitto (32bit embedded console, 48 MHz, 36 kB RAM):
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SDL (PC):
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Arduboy (8bit Arduino console, 16 MHz, 2.5 kB RAM):
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terminal:
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Gamebuino META (Arduino 32bit console, 48 MHz, 32 kB RAM):
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features
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--------
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- Very **fast, small and efficient**.
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- Uses **only integer math** (32bit). The tiny version should only require 16bit, but isn't completed.
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- **No dependencies** (uses only stdint standard library), extremely portable.
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- **Single header**, KISS, suckless.
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- Advanced rendering of **variable height floor and ceiling**.
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- **Textured walls and floor**.
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- **Depth information** (e.g. for fog or z-buffer rendering).
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- **Camera shearing** (looking up/down).
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- Camera movement with **collisions**.
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- Partial support for **opening door**.
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- **Pure C99**, tested to run as C++ as well.
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- Optional framework **functions that handle the whole rendering**.
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- Still **flexible** -- pixels are left for you to draw in any way you want.
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- **Tested on many platforms**:
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- PC (little endian, 64bit GNU)
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- PowerPC emulator (big endian)
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- compilers: gcc, clang, emscripten (web browser, JavaScript transpile)
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- Arduboy (only experimental)
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- Pokitto (32bit resource-limited embedded ARM)
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- Gamebuino META (32bit resource-limited embedded ARM)
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- TODO:
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- Android
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- Windows
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- **Many compile-time options** to tune the performance vs quality.
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- **Well commented** and formatted code, with examples. Automatic documentation (comments + provided Doxyfile).
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- Completely **free of legal restrictions**, do literally anything you want.
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**NOTE**: Backwards compatibility isn't a goal of this libraray. It is meant to
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be an as-is set of tools that the users is welcome to adjust for their
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specific project. So new features will be preferred to keeping the same
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interface.
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how to use
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----------
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**Don't forget to compile with -O3!** This drastically improves performance.
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For start take a look at the [helloWorld.c](https://gitlab.com/drummyfish/raycastlib/blob/master/programs/helloWorld.c) program and other examples.
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For more examples see my [Pokitto demos](https://gitlab.com/drummyfish/Pokitto-Raycasting) repository.
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Also see **the library code itself**, it is meant to be self-documenting -- you'll find the description of a lot of things at the start of the file.
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The basic philosophy is:
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- The library implements only a **rendering back-end**, it doesn't perform any drawing to the actual screen,
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hence there is no dependency on any library such as OpenGL or SDL. It just calls your front-end function
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and tells you which pixels you should write. How you do it is up to you.
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- Before including the header, define `RCL_PIXEL_FUNCTION` to the name of a function you will use to
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draw pixels. It is basically a fragment/pixel shader function that the library will call. You will
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be passed info about the pixel and can decide what to do with it, so you can process it, discard it,
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or simply write it to the screen.
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- Call `RCL_renderSimple` or `RCL_renderComplex` to perform the frame rendering. This will cause the
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library to start calling the `RCL_PIXEL_FUNCTION` in order to draw the frame. You can optionally write
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a similar function of your own using the more low-level functions which are also provided.
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- The library gets info about the world (such as floor or ceiling height) via *array* functions
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(`RCL_ArrayFunction` type) -- functions that take *x* and *y* coordinates of a square and return given
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information. This way you are free to not only fetch the map data from an array, but also generate
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the world procedurally if that is what you want.
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- Fixed point arithmetics is used as a principle, but there is no abstraction above it, everything is simply
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an integer (`RCL_Unit` type). The space is considered to be a dense grid, where each world square
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has a side length of `RCL_UNITS_PER_SQUARE` units. Numbers are normalized by this constant, so e.g.
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the sin function returns a value from `-RCL_UNITS_PER_SQUARE` to `RCL_UNITS_PER_SQUARE`.
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license
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-------
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Everything is CC0 1.0 (public domain, https://creativecommons.org/publicdomain/zero/1.0/) + a waiver of all other IP rights (including patents).
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I've written all code completely myself from scratch, the art used in demos is either my own released under CC0 or someone else's released under CC0.
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This is not a mandatory condition, but please consider supporting free software and free culture by using free licenses and/or waivers.
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If you'd like to support me or just read something about me and my projects, visit my site: [www.tastyfish.cz](http://www.tastyfish.cz/).
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