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100 lines
4 KiB
Markdown
100 lines
4 KiB
Markdown
# raycastlib
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Ray casting library for (not only) limited-resource computers.
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If you like this, you may also like my similar project: [small3dlib](https://gitlab.com/drummyfish/small3dlib).
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eye-candy previews
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------------------
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Pokitto:
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SDL:
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Arduboy:
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terminal:
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Gamebuino META:
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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).
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- No dependencies (uses only stdint standard library), extremely portable.
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- Single header, KISS.
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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.
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- Completely free of legal restrictions, do literally everything 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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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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The basic philosophy is:
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- The library implements only a rendering back-end, it doesn't permorm 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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license
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-------
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Everything is CC0 1.0 + a waiver of all other IP rights (including patents). Please share your own software as free and open-source.
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