bad

A C/C++ SIMD math library for video game programming and connected fields, targeting x86, x86-64 and ARM architectures. bad aims at providing a math library, but might be extended to offer systems, modules and algorithms commonly used in the video game industry (collision, physics, etc.).

Disclaimer

Because I am working on this library primarily to learn, it is a work in progress in its early days. It is missing a lot of features and may contain dirty and incorrect code.

Goals of the library

• Provide a cross-platform optimized API
• Compile with Clang, GCC and MSVC
• Compile and run under Windows and Linux
• Both C and C++ compatible
• Take advantage of the available SIMD instruction sets
• Offer the best performance for mathematics (and other modules and algorithms commonly found in the video game industry) for low energy consumption
• Provide a library with no dependencies that relies as little as possible on the standard C/C++ library

Current state of the library

• Tested on a laptop with an AMD x86-64 CPU (Ryzen 7 5800H)
• Compiled with Clang for both C and C++
• Compiled under Windows 10
• C++ compatible
• Takes advantage of MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2 and FMA intrinsics
• Contains only common single-precision floating-point vector operations
• Has no dependency, but relies on stdint.h

Repository overview

• src/bad/: the library. If you want to use bad in your project, this is probably the only directory you need
  • common/: common operations likely to be used throughout the rest of the library
  • detect/: context detection around the library
  • math/: math functions
  • types/: where scalar, simd and math types are defined. No functions are contained here, only declarations
  • bad.h: included accross all headers, currently used solely for wrapping sources in an optional namespace
  • debug.h: debug-mode runtime checks through macros
  • qualifiers.h: a variety of qualifiers used to affect how the compiler generates code
• test/: unit tests on important and/or non-trivial functions
• build.bat: custom compilation script for Windows 10 with Clang. Can be called with build to build the library, build test, build asm, build run, build clean
• RESOURCES.md: a collection of knowledge that helped me learn

To do

General:

• Work on C/C++ interoperability
• Work on Linux support
• Support compilation with GCC and MSVC
• Support compilation under ARM
• Add support for more SIMD instruction sets? (RISC-V "V", PowerPC's AltiVec, MIPS' MSA, ARM's Helium?)
• Take endianness in consideration

Common:

• Implement f32xn and maskn, a general vector type built on top of the most suited SIMD ISA available for the needs of the user
• Explore non-temporal loads and stores
• Explore possible implementation of types whose size is not a multiple of the available vector width (vec2 and vec3 for instance)
• Remove the dependency on stdint.h if possible in types.h
• Learn about interoperability and penalties between ISA (SSE <--> AVX for instance), and manage them

Tests:

• Extend tests to all functions, trivial or not
• Improve testing framework?

Math:

• Migrate calculus/mathematical functions in common/f32x4.h to math
• Implement common calculus functions such as power, exponential, log, tan...
• Implement 4-dimensional vector
• Implement 3-dimensional vector
• Implement quaternion
• Implement 4x4, 3x4 and 3x3 matrices
• Implement math types conversion functions
• Implement common splines

Collisions & intersections:

• Implement shapes
• Implement collision algorithms

Physics:

• Implement kinematic

License

bad is licensed under the MIT license