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0df33d1975
Technically unimpressive, but I had to go through quite a good amount of
changes. Here is the full changelog to make everything work:
* Ensure `ResetPlatform` is always called to avoid memory leaks
* Add `g_RawVram` to emulate the PS1 VRAM
* ~~The engine will load the optional file `disks/vram.bin`, a RAM dump
from an emulator~~
* SDL2 will create 256x256 textures on-the-fly whenever a specific tpage
is requested via `GetVramTexture`
* The function `GetVramTexture` caches the last called tpage to avoid
tanking the performance
* `GetVramTexture` for only renders 4bpp and 8bpp textures with their
specified palette
* Remove `SDL2_image` as the font is now loaded straight from the VRAM
* Calling `VSync` will call the set callback, which the game uses for
DMA operations
* `MyLoadImage` is not yet implemented, but it is a placeholder to then
interact with `g_RawVram`
* The menu font now uses the texture found in the VRAM
* Plugged a custom version of `LoadFileSim`
* The file `sim_pc.c` is similar to the original game's code but it is
used here to load files from custom paths
* Using F5, F6 or F7 can dump the VRAM content on-screen, respectively
in 16bpp, 8bpp and 4bpp
There are new graphical glitches on the font. In some occasions it
appears black. It seems to be related to a flag in `P_TAG.code`. I plan
to dig into it when I can render entities on screen to avoid potential
mistakes. The same problem is present for the first half of Alucard's
portrait. It seems to be related when a texture is transparent? 🤷
I am not sure why the font is completely corrupted when entering in the
Equip menu. It is hard to understand if I introduced any regression.
Maybe the glitch was always there but it was hidden since I was always
forcing the font texture to be rendered.
EDIT: Implemented `LoadImage`, `SaveImage` and `ClearImage`
Castlevania: Symphony of the Night Decompilation
A work-in-progress decompilation of Castlevania Symphony of the Night for Sony PlayStation 1 and Sega Saturn. It aims to recreate the source code from the existing binaries using static and/or dynamic analysis. The code compiles byte-for-byte to the same binaries of the game, effectively being a matching decompilation.
It currently supports the following versions of the game:
usthe reference build with the serial number SLUS-00067hdan unreleased PS1 Japanese build found in Castlevania: Dracula X Chronicles game datasaturnthe port created by an external development team
This repo does not include any assets or assembly code necessary for compiling the binaries. A prior copy of the game is required to extract the required assets.
Bins decomp progress
| File name | Code coverage | Decomp functions | Description |
|---|---|---|---|
| SLUS_000.67 | N/A | N/A | Shared libraries |
| DRA.BIN |  |
 |
Game engine |
| BIN/RIC.BIN |  |
 |
Playable Richter |
| BIN/WEAPON0.BIN |  |
 |
Equippables |
| ST/CEN/CEN.BIN |  |
 |
Center |
| ST/DRE/DRE.BIN |  |
 |
Nightmare |
| ST/MAD/MAD.BIN |  |
 |
Debug Room |
| ST/NO3/NO3.BIN |  |
 |
Entrance (first visit) |
| ST/NP3/NP3.BIN |  |
 |
Entrance |
| ST/NZ0/NZ0.BIN |  |
 |
Alchemy Laboratory |
| ST/SEL/SEL.BIN |  |
 |
Title screen |
| ST/ST0/ST0.BIN |  |
 |
Final Stage: Bloodlines |
| ST/WRP/WRP.BIN |  |
 |
Warp Room |
| ST/RWRP/RWRP.BIN |  |
 |
Warp Room (reverse) |
| SERVANT/TT_000.BIN |  |
 |
Bat Familiar |
Code coverage means how many bytes of code have been successfully converted from assembly into C code, while decomp function is how many functions have been successfully decompiled.
Useful links
Decompiling a game is a mastodontic task. If you have some basic programming skills, please join us in this journey. Any contribution will be very appreciated!
Special thanks
This project is possible thanks to the hard work of tools provided by the Decompilation community:
- mips2c from @matt-kempster to decompile MIPS assembly into C. This has proven to be more accurate than Hexrays IDA and Ghidra.
- splat from @ethteck to disassemble code and extract data with a symbol map. This tool provides the fundamentals of the SOTN decomp.
- asm-differ from @simonlindholm to know how the decompiled code compares to the original binary.
- decomp-permuter from @simonlindholm to pick different versions of the same code that better matches the original binary.
- maspsx by @mkst to replicate the customized assembler used in the official PSX SDK.
- decomp.me by @ethteck, @nanaian and @mkst to provide a collaborative decompilation site to share and contribute to work-in-progress decompiled functions.
- frogress by @ethteck to store and retrieve progression data.
- esa-new by @mkst as an inspiration on how to set-up a PS1 decompilation project.
- oot as an inspiration of what it is possible to achieve with a complete decompiled video game.