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113 lines
5.3 KiB
Markdown
113 lines
5.3 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 multiple platforms** (PC, Arduboy, Pokitto, Gamebuino META).
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- **Many compile-time options** to tune the performance vs quality.
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- **Well commented** and formatted code. 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 [testTerminal.c](https://gitlab.com/drummyfish/raycastlib/blob/master/programs/testTerminal.c) program.
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It is only a little bit more complex than a simple hello world.
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For more examples see the other files, plus my [Pokitto demos](https://gitlab.com/drummyfish/Pokitto-Raycasting) repository,
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which contains some better documented example code, including a [very simple hello world](https://gitlab.com/drummyfish/Pokitto-Raycasting/blob/master/helloRay.cpp).
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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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TODO
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----
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- Transparency (conditional ray passing through).
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- Doors in the middle of squares.
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- Rolling doors for `RCL_renderComplex`.
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- Possibly merge all rendering functions into one.
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- Fix rendering bug that happens at the boundary of positive and negative square coords.
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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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The art used in demos is either my own released under CC0 or someone else's released under CC0.
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Please support 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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