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+Although most of the code is platform-independent, some per-platform functionality is required.
+
+By default I try to automatically define appropriate backends for your system in `Core.h`. Define ```CC_BUILD_MANUAL``` to disable this.
+
+## Before you start
+* IEEE floating support is required. (Can be emulated in software, but will affect performance)
+* int must be 32-bits. 32-bit addressing (or more) is required.
+* Support for 8/16/32/64 integer types is required. (your compiler must support 64-bit arithmetic)
+* At least around 2 MB of RAM is required at a minimum
+* At least 128 kb for main thread stack size
+
+In other words, the codebase can theroetically be ported to any modern-ish hardware, but not stuff like a UNIVAC machine, the SuperFX chip on the SNES, or an 8-bit microcontroller.
+
+## Supported platforms
+**Note:** Some of these machines are just virtual machines. Should still work on real hardware though.
+
+#### Tier 1 support
+These platforms are regularly tested on and have executables automatically compiled for. (see buildbot.sh)
+
+|Platform|Machine|Notes|
+|--------|-------|-----|
+|Windows x86/x64 | Windows 7 |
+|macOS x86/x64 | macOS 10.12 |
+|Linux x86/x64 | Xubuntu 14 | 
+|Web client | Chrome |
+
+#### Tier 2 support
+These machines are far less frequently tested on, but are otherwise same as tier 1 support.
+
+|Platform|Machine|Notes|
+|--------|-------|-----|
+|Windows x86 | Windows 2000 |
+|Windows x86 | 98 + KernelEX | Updating doesn't work
+|Windows x64 | Windows 10 |
+|ReactOS | ReactOS |
+|Linux x64 | Arch linux |
+|Linux x64 | Linux Mint |
+|Linux x64 | Kubuntu |
+|Linux x64 | Debian |
+|Linux x64 | Fedora |
+|Linux x86/x64 | Lubuntu |
+|Web client | Firefox |
+|Web client | Safari |
+|Web client | Edge | Cursor doesn't seem to disappear
+
+#### Tier 3 support
+The game has been compiled and run on these platforms before. It may or may not still compile for them.
+
+I don't really test these platforms at all, only when I suspect some changes to the code might impact them.
+
+|Platform|Machine|Notes|
+|--------|-------|-----|
+|macOS x86 | macOS 10.4 |
+|FreeBSD x86 | FreeBSD | x64 should work too |
+|NetBSD x86 | NetBSD | x64 should work too |
+|OpenBSD x86 | OpenBSD | x64 should work too |
+|Solaris x86 | OpenIndiana | x64 should work too |
+|macOS PPC | macOS 10.3 | PPC64 completely untested |
+|Linux PPC | Debian | Issues with colour channels incorrectly swapped? |
+|Linux ARM | Raspberry pi | ARM64 should work too |
+|Linux SPARC | Debian | Didn't really work due to lack of 24-bit colours |
+|Linux Alpha | Debian | 
+|HaikuOS | Nightly | 
+
+## Porting
+
+Listed below are the requirements for implementing each platform-dependent file.
+You should try to take advantage of existing backends when porting to other platforms.
+Only cross platform backends are listed below.
+
+### Platform
+General platform specific functionality.
+
+- Get exe path, start/exit process, open url in browser
+- Dynamic library management
+- Allocate, free, copy, set memory
+- Current system time, stopwatch time
+- File I/O, Directory I/O, Socket I/O
+- Threading, signalable wait, mutex
+- Drawing/measuring native font
+- Native font text drawing and measuring
+- Encrypt/decrypt data, getting command line args
+
+Define:
+- ```CC_BUILD_POSIX``` - Use posix API
+
+posix note: Some functions are not covered. (stopwatch, getting exe path, open url in browser)
+These must still be implemented for each operating system
+
+### Window
+Create a window, show a dialog window, set window contents, keyboard/mouse input
+
+Also monitor size, clipboard, cursor, raw relative mouse movement (optional)
+
+Define:
+- ```CC_BUILD_X11``` - Use X11/XLib (unix-ish) (glX)
+- ```CC_BUILD_SDL``` - Use SDL library (SDL)
+
+If using OpenGL, also OpenGL context management
+
+### Logger
+Dump registers and backtrace, log unhandled errors (e.g. invalid memory read)
+
+Define:
+- ```CC_BUILD_POSIX``` - use POSIX api
+
+posix note: Register access is highly dependent on OS and architecture.
+
+(e.g. Linux uses &r.gregs[REG_EAX] while FreeBSD uses &r.mc_eax)
+
+### Audio
+Play multiple audio streams with varying sample rates
+
+Define:
+- ```CC_BUILD_OPENAL``` - use OpenAL
+- ```CC_BUILD_NOAUDIO``` - stub audio implementation (silent)
+
+### 3D Graphics
+Texturing, depth buffer, alpha, etc (See Graphics.h for full list)
+
+Define:
+- ```CC_BUILD_D3D9``` - Use Direct3D9
+- ```CC_BUILD_GL``` - Use OpenGL (1.5/1.2 + ARB_VERTEX_BUFFER_OBJECT)
+- ```CC_BUILD_GL11``` - Use OpenGL 1.1 features only
+- ```CC_BUILD_GLMODERN``` - Use modern OpenGL shaders
+- ```CC_BUILD_GLES``` - Makes these shaders compatible with OpenGL ES
+
+### HTTP
+HTTP, HTTPS, and setting request/getting response headers
+
+Define:
+- ```CC_BUILD_HTTPCLIENT``` - use built in simple HTTP backend
+- ```CC_BUILD_CURL``` - use libcurl for HTTP
+
+Supporting connection reuse is highly recommended. (but not required)