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@ -30,15 +30,16 @@ PC (SDL, offline rendering, terminal):
## features ## features
- Very **fast, small and efficient**. - Very **fast, small and efficient**.
- Uses **only integer math** (32bit). - Uses **only 32bit integer math** by default, with a compile time option to use wider types if needed.
- **No dependencies** (uses only stdint standard library), extremely portable. - **No dependencies** (uses only stdint standard library), extremely portable.
- **Single header**, KISS, suckless. - **Single header**, KISS, suckless. No OOP, no design patterns, just nicely documented functions.
- **No dynamic heap allocation.** - **No dynamic heap allocation.**
- **Pure C99**, tested to run as C++ as well. - **Pure C99**, tested to run as C++ as well.
- Still **flexible** -- pixels are left for you to draw in any way you want with a custom fragment-shader like function. - Still **flexible** -- pixels are left for you to draw in any way you want with a custom fragment-shader like function.
- **Perspective correction**, 3 modes: none (linear only), full (per-pixel), approximation (per-N-pixels). - **Perspective correction**, 3 modes: none (linear only), full (per-pixel), approximation (per-N-pixels).
- **Different drawing strategies** to choose from: none, z-buffer (none, full, reduced), triangle sorting (back-to-front, fron-to-back with stencil buffer). - **Different drawing strategies** to choose from: none, z-buffer (none, full, reduced), triangle sorting (back-to-front, fron-to-back with stencil buffer).
- Triangles provide **barycentric coordinates**, thanks to which practically anything that can be achieved with OpenGL can be achieved (texturing, shading, normal-mapping, texture fitering, transparency, PBR, shadow mapping, MIP mapping, ...). - Triangles provide **barycentric coordinates**, thanks to which practically anything that can be achieved with OpenGL can be achieved (texturing, shading, normal-mapping, texture fitering, transparency, PBR, shadow mapping, MIP mapping, ...).
- **Different near plane coliision handling strategies**, several options: cull, push, geometrically correct clip, geometrically and barycentric correct clip. Choose the one that best suits you program.
- **Top-left rasterization rule**, pixels of adjacent triangles don't overlap or have holes (just like in OpenGL). - **Top-left rasterization rule**, pixels of adjacent triangles don't overlap or have holes (just like in OpenGL).
- **Tested on many platforms**: - **Tested on many platforms**:
- PC (little endian, 64bit GNU) - PC (little endian, 64bit GNU)
@ -65,14 +66,14 @@ interface.
## why? ## why?
You just need to make a small mini 3D game, quick 3D animation or visualization and don't want to go through the horror of learning and setting You just need to make a small mini 3D game, quick 3D animation or visualization and don't want to go through the horror of learning and setting
up OpenGL, installing drivers and libraries? Don't want to be tied to HW, 3rd party API or libraries and their dependencies? Don't want to install up OpenGL or Vulkan, installing drivers, learning complex APIs and libraries? Don't want to be tied to HW, 3rd party API or libraries and their
gigabytes of heavy super ultra graphics engines just to play around with a few low poly models? You want to create extremely portable 3D dependencies? Don't want to install gigabytes of heavy super ultra graphics engines just to play around with a few low poly models? You need a
graphics that will run on small and obscure platforms that don't have OpenGL, good specs or even standard C library? Want to just render something simple software renderer as a fallback to your main renderer? You want to create extremely portable 3D graphics that will run on small obscure
offline simply without caring about highest rendering speed? You want to toy around with modifying something in the rendering pipeline that you embedded platforms that don't have OpenGL, good specs, FPU unit or even standard C library? Want to just render something offline simply without
can't easily do or debug in OpenGL (such as the rasterization algorithm)? Want to hack around in the demo scene? Want to create something public caring about highest rendering speed? You want to toy around with modifying something in the rendering pipeline that you can't easily do or debug
domain and need a public domain renderer? Or just don't want to be bothered by conditions such as proper attribution or copyleft? in big frameworks (such as the rasterization algorithm)? Want to hack around in the demo scene? Want to create something public domain and need a
public domain renderer? Or just don't want to be bothered by conditions such as proper attribution or copyleft? You want to create an authentic
This library may help you. retro wobbly PS1 style graphics? Then this library may help you.
## limitations ## limitations
@ -83,7 +84,9 @@ And advantages at the same time :)
- There is **no far plane**. - There is **no far plane**.
- There is **no subpixel accuracy** (PS1 style graphics). - There is **no subpixel accuracy** (PS1 style graphics).
- There is **no antialiasing**, but you can still achieve it by supersampling (render in higher resolution and downscale) or filters like FXAA. - There is **no antialiasing**, but you can still achieve it by supersampling (render in higher resolution and downscale) or filters like FXAA.
- Due to the limitations of 32bit integer arithmetics some types of movement (particularly camera) **may look jerky, and artifact may appear** in specific situations. - At the moment there is no wireframe rendering, but you can simulate it easily (see model viewer example), or write it by hand (drawing lines is not that hard).
- Due to the limitations of using only integer arithmetics, some types of movement (particularly camera) **may look jerky, and artifact may appear** in specific situations. This can partially be fixed with `S3L_USE_WIDER_TYPES`.
- There's no extensive error and memory safety checking, you're supposed to not try to crash the library.
## how to use ## how to use
@ -93,7 +96,7 @@ For more see the other examples and **the library code itself**, it is meant to
The basic philosophy is: The basic philosophy is:
- The library implements only a rendering back-end, it doesn't perform any drawing to the actual screen, - The library implements only a rendering back-end, it doesn't perform any drawing to the actual screen itself,
hence there is no dependency on any library such as OpenGL or SDL. It just calls your front-end function hence there is no dependency on any library such as OpenGL or SDL. It just calls your front-end function
and tells you which pixels you should write. How you do it is up to you. and tells you which pixels you should write. How you do it is up to you.
- Before including the header, define `S3L_PIXEL_FUNCTION` to the name of a function you will use to - Before including the header, define `S3L_PIXEL_FUNCTION` to the name of a function you will use to
@ -101,7 +104,7 @@ The basic philosophy is:
be passed info about the pixel and can decide what to do with it, so you can process it, discard it, be passed info about the pixel and can decide what to do with it, so you can process it, discard it,
or simply write it to the screen. or simply write it to the screen.
- Also init screen resolution, either by defining `S3L_RESOLUTION_X` and `S3L_RESOLUTION_Y` (before including the library) or by setting `S3L_resolutionX` and `S3L_resolutionY` variables. - Also init screen resolution, either by defining `S3L_RESOLUTION_X` and `S3L_RESOLUTION_Y` (before including the library) or by setting `S3L_resolutionX` and `S3L_resolutionY` variables.
- Use the provided Python tools to convert your model and textures to C arrays, include them in your - Use the provided Python tools to convert your models and textures to C arrays, include them in your
program and set up the scene struct. program and set up the scene struct.
- Init the 3D models and the scene with provided init functions (`S3L_init*`), set the position of the camera. - Init the 3D models and the scene with provided init functions (`S3L_init*`), set the position of the camera.
- Call `S3L_newFrame` to prepare for rendering, then call `S3L_drawScene` on the scene to perform the frame rendering. - Call `S3L_newFrame` to prepare for rendering, then call `S3L_drawScene` on the scene to perform the frame rendering.
@ -109,7 +112,7 @@ The basic philosophy is:
modify the function or write a similar one of your own using the more low-level functions which are modify the function or write a similar one of your own using the more low-level functions which are
also provided. also provided.
- Fixed point arithmetics is used as a principle, but there is no abstraction above it, everything is simply - Fixed point arithmetics is used as a principle, but there is no abstraction above it, everything is simply
an integer (`S3L_Unit` type). The space is considered to be a dense grid, and what would normally be an integer (`S3L_Unit` type). The space is considered to be a uniform dense grid of discrete points, and what would normally be
a 1.0 float value is an int value equal to `S3L_FRACTIONS_PER_UNIT` units. Numbers are normalized by this a 1.0 float value is an int value equal to `S3L_FRACTIONS_PER_UNIT` units. Numbers are normalized by this
constant, so e.g. the sin function returns a value from `-S3L_FRACTIONS_PER_UNIT` to `S3L_FRACTIONS_PER_UNIT`. You have to constant, so e.g. the sin function returns a value from `-S3L_FRACTIONS_PER_UNIT` to `S3L_FRACTIONS_PER_UNIT`. You have to
pass numbers of this format to the library functions, but of course you may chooe to use floats in other places of your program. pass numbers of this format to the library functions, but of course you may chooe to use floats in other places of your program.