DamonPS2



DamonPS2 is a mh:awesomegames:PlayStation 2 emulator for Android devices developed by a Chinese company named DamonPlay Technology Co. Ltd. It was delisted from mainstream Android digital distribution platforms after the creators of PCSX2, a freeware PS2 emulator for PC, filed a DMCA takedown against the developers under the accusation of stealing code from them, but later brought back.

Why It Sucks

 * 1) The emulator comes with a free version, as well as a paid version. The differences between the two versions are nonexistent, meaning that the users of the paid version are going to spend $10 for no reason at all.
 * 2) * The free version, however, has many micro-transactions. For example, to run a game you need to have two coins, otherwise the game would not start. Not to mention, it's also filled with tons of ads.
 * 3) * Despite not being free, the performance leaves a lot to be desired and only few games run correctly.
 * 4) There are no hardware requirements listed for this emulator, which can be hard to know how much RAM and which GPU your device needs to have to run PlayStation 2 games on your Android device.
 * 5) It uses PCSX2's core, a free and  open-source emulator for PC, meaning that they are making money off of someone else's work.  Even worse, they have a core for PPSSPP too, a PSP emulator for PC and Mobile, also not belonging to the original creator.
 * 6) *Now, PCSX2 and PPSSPP are both licensed under GNU GPL v.2 or later, which does lets you make money from them as long as you don't make your version closed-source and/or add DRM, and to place your name on it, so people can distinguish it from other versions and to protect the reputations of other maintainers (e.g. original ones). However, DamonPlay added DRM and made it propietary, both of which are against the license terms, thus making the emulator, both on its own existing on the Google Play Store, and owning it, borderline illegal.
 * 7) It has an unnecessary built-in DRM system as stated, which runs afoul of GNU GPL, possibly to prevent fake In-app purchases, but also a sign that DamonPS2 is probably doing operations that do harm to the device.
 * 8) * And as of version 3.0 it requires constant internet connection, leaving a lot to speculate it is selling user's data to advertisers, strenghing the DRM.
 * 9) * The owner of DamonPS2 has also attempted to steal trademarks of various emulator's names and icons in the US, EU and China. While in China wouldn't be that much of an issue, the same couldn;t be said in the USA and European Union.
 * 10) Some games run with a ton of bugs and glitches, due to bad emulation.
 * 11) Unnecessary and quite suspicious app permissions such as asking for your location and your contacts.

Controversy
The PCSX2 team and others accused the developers of DamonPS2 of using the code from the PCSX2 project and violating its GPL v.2 license in a blog post.

The evidence provided by PCSX2 team include:


 * GameIndex.dbf file distributed with the emulator contained patches that were specific to PCSX2.
 * CDVD strings, such as the message returned when a PSX/PSone disc is inserted in emulated PS2, is the same to PCSX2.
 * Matching file structure and graphical output (including glitches) that mirrors GSdx in PCSX2 is found.
 * Instead of writing their own MIPS to ARM dynarec to replace PCSX2's, DamonPS2 uses an x86 to ARM dynarec on top of PCSX2's MIPS to x86.

On Baidu, DamonPS2 devs replied to the accusations stating: (P.S. reference website is in Chinese)


 * GameIndex.dbf do come from PCSX2, but such file is an index file that including game title names (even though the patches were still being used), and this was removed (or baked into the binary) as in version 0.95.
 * CDVD (contained in libserial.so) only used the same function names as PCSX2, the actual function is different, and such library has been removed (or baked into the binary) as in version 0.95.
 * PCSX2 is a benchmark standard for DamonPS2 accuracy-test while developing, so such a standard made DamonPS2 behavior leaned to PCSX2, which they claim explain the identical graphical output as PCSX2;
 * The DamonPS2 development team repeatedly emphasized that the Chinese government’s copyright agency has reviewed its source code and the source code of its emulator has obtained copyright certification in China, and copyright of all source code protected by the Chinese government.

DamonPS2 was taken off Google Play for a short time following a DMCA request from PCSX2. However, the PCSX2 team had posted publicly that they would be sending a DMCA request, and it seems DamonPS2 pulled their emulator off the store before and during the review process.

Videos
One example of how poor DamonPS2's emulation is.

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