Abe's Amazing Adventure

Abe's Amazing Adventure - ArcaOS / OS/2 Port Notes ==================================================== This document covers building and running Abe's Amazing Adventure on ArcaOS (and compatible OS/2 environments) using SDL2 and GCC 9.2 / kLIBC. The original game was written for Linux/SDL1. This port migrates the rendering and audio layers to SDL2 and adds the OS/2-specific build support needed to produce a native PM executable. Requirements ------------ - ArcaOS 5.x (tested on ArcaOS 5.1 / OS2 eCS 2.45) - GCC 9.2 with kLIBC (available via the ArcaOS package manager / RPM) - SDL2 (SDL2_dll.a + headers under C:/usr/include/SDL2) - SDL2_mixer (SDL2_mixer_dll.a + headers) - WLINK (Open Watcom linker, used via EMXOMFLD) - GNU make - REXX (standard OS/2 component) Directory layout ---------------- abe.exe Compiled binary abe_os2.txt This file README.md General readme compile-abe.cmd REXX build script run-abe.cmd REXX launch script src/ C source files src/Makefile.os2 OS/2-specific makefile images/images.tar Game graphics (TAR archive) sounds/ Sound effects (WAV) and music (OGG) maps/ Map data files savegame/ Used at runtime for temp BMP extraction Building -------- Open an OS/2 command prompt (CMD.EXE) in the Abe directory and run: compile-abe.cmd This sets the required environment variables, enters the src/ directory, runs make with Makefile.os2, and writes the build log to compile-abe.log. The environment variables set by the script are: EMXOMFLD_TYPE=WLINK EMXOMFLD_LINKER=wl.exe EMXOMFLD_PRELINK=0 These are required so that the GCC driver calls WLINK (Open Watcom) rather than EMXOMFLD for linking, producing a proper OS/2 LX executable. Compiler flags used: -O2 -Zomf -Zmt -Wall -DBASE_DIR=. -Zstack 512 (linker) The linker also requires abe.def (a module definition file included in src/). Running ------- From the Abe directory: run-abe.cmd This changes to the Abe directory, launches abe.exe in windowed mode, and captures stderr to run-abe.log for diagnostics. You can also run directly: abe.exe --window or in fullscreen (if your display driver supports it): abe.exe Controls -------- Arrow keys Move / climb Space Jump Enter Use a balloon Esc Quit Port changes from the original SDL1 source ------------------------------------------ The following changes were made to port from SDL1 to SDL2 on OS/2: 1. SDL2 rendering model The game uses a virtual SDL_Surface (screen) as an off-screen render target. Each frame, presentScreen() letterbox-scales it onto the real SDL_Window surface and calls SDL_UpdateWindowSurface(). No SDL_Renderer or GPU textures are used; all drawing remains software-surface based. 2. SDL2 API replacements - SDL_SetVideoMode -> SDL_CreateWindow / SDL_GetWindowSurface - SDL_Flip -> SDL_UpdateWindowSurface - SDL_SetAlpha -> SDL_SetSurfaceAlphaMod / SDL_SetSurfaceBlendMode - SDL_SetColorKey -> SDL_SetColorKey (SDL2 signature differs) - SDL_mixer init -> Mix_OpenAudio with SDL2 parameters - SDL_RWFromFP -> SDL_RWFromFP (still available in SDL2) 3. OS/2 path separator Directories.h defines PATH_SEP as "\\" for OS/2 (__OS2__ / __EMX__). An #undef PATH_SEP guard prevents redefinition warnings when Common.h is included after Directories.h. 4. Save-game directory (mkshuae) On Linux, the game stores saves in ~/.abe/. On OS/2 it uses .\savegame\. The mkshuae() function was gated to skip OS/2; the guard was removed so the directory is created at startup using kLIBC's two-argument mkdir(). This directory is also used as the temporary extraction path for BMP files read from images.tar. 5. TAR image loader fix The custom TAR parser in Image.c had a bug: when a TAR entry had filesize == 0 (directory entries, etc.), blocks_read was 0 but the parser still entered data-reading mode, consuming all subsequent real file data as if it were padding. Fixed by skipping data mode entirely when blocks_read == 0. 6. Map tile bounds checking The map files reference tile image indices beyond the loaded images[] array (which holds 256 entries). Added a sanitization pass in loadMapPath() that replaces any out-of-bounds or unloaded tile index with EMPTY_MAP after decompression. Also added bounds guards in decompressMap() and compressMap() for safety. 7. Build system src/Makefile.os2 added for GCC/kLIBC. Produces .obj (OMF) objects and links with WLINK via the EMXOMFLD wrapper. compile-abe.cmd and run-abe.cmd are REXX scripts with CRLF line endings (required by OS/2 REXX) that automate the build and launch. Known issues / limitations -------------------------- - Some map tiles reference image indices beyond those present in the bundled images.tar. These tiles render as empty space. This is a data issue in the original map files, not a runtime error. - Fullscreen mode depends on your display driver. --window is recommended. - Music playback (OGG via SDL2_mixer) requires the SDL2_mixer DLL to be on the LIBPATH. If music does not play, verify SDL2_MIXER.DLL is accessible. - The built-in map editor (GOD_MODE) has not been tested on OS/2. Contact ------- Original game: Gabor Torok <cctorok@yahoo.com> http://abe.sf.net ArcaOS port: Martin Iturbide