Gaming on Linux


Recently, I admit that Chromium is faster and smoother than Firefox. And now, for me, Firefox is my primary bookmark manager, reference manger with Zotero, and best ever download manager; yet Chromium is my primary web browser.

This is just like Windows is no more an Operating System for me, but a game console. I have no choice to admit this because playing games on Linux, is still far behind from Windows. The main reason is the developers usually target on Windows instead of Linux. However, it is truly worth for me to optimise the functionality of a computer by running Linux and sacrificing the gaming potentiality of Windows.

Native, Emulators, and Steam

There are several methods to play games on Linux. Steam is one of the methods, but it is not my favourite. Other than that, there are native games in Linux, one of my favourite is Cave Story. Another solution is using emulators, such as DOXBox, VBA-M, MAME, etc. However, not all emulators work perfectly, especially PS2 emulators.

WINE

WINE (WINE Is Not Emulator) is my another favourite. It allows to run Windows applications including some games. Yet, it does not work perfectly, not all games work. I have successfully used it to play KOEI Sangokushi (Romance of the Three Kingdoms) 12 and The Sims 4. WINE works fine with these games. However, some 3D games such as Assassin’s Creed II and Dead or Alive 5 Last Round do not work for me. Moreover, latest version of WINE does not guarantee better compatibility of all games. Some games work better with a certain version of WINE; some games requires certain patched version of WINE.

Virtualisation

So, the native Windows is still an attractive solution for playing games. Therefore, virtualisation is the possible solution. (LXC and Docker do not work, because they are containers.)

VirtualBox

VirtualBox is my favourite hypervisor because it is very easy to use. VirtualBox allows Direct3D yet it is under experimental. It has to be installed through the Guest Addition ISO image. However, I found that the Direct3D driver installed is wined3d.dll. As a result, the 3D rendering produces the same problem as in using WINE for certain games. As a conclusion, using VirtualBox to play 3D games does not work as expected.

QEMU/KVM

Since VirtualBox does not work with 3D games, I recently tried QEMU with KVM. Because I read some articles (this and this) regarding QEMU/KVM, it can virtualise the 3D graphics card. However, this requires 2 graphics cards: one for the host machine, another for guest machine. And this method uses VFIO, which is very troublesome.

Furthermore, there is a Virgil 3D project which targets to produce virtual 3D GPU. I studied a little, yet I didn’t try to compile it, because it seems like very troublesome. As a conclusion, QEMU/KVM does not work either.

VMware Player

So, the final solution I tried recently was VMware Player, which is free for non-commercial use. Installation of the VMware Player version 7 requires GCC 5.1.0 in Arch Linux. In this case, I have to install GCC 5.1.0 and compile the modules, then downgrade to GCC 4.9.2 again.

VMware Player is very similar to VirtualBox, but the VM management less useful than VirtualBox. Besides that, some VM configurations have to be done manually using text editor.

After some configurations and testing, I found that it works as the best among the virtualisation software. It is better than VirtualBox.

VMware Player 3D configuration

To enable VMware 3D graphics for Direct3D, firstly we have to make sure our host machine (Linux) allows “direct rendering” by entering the following command,

glxinfo | grep direct

Then, to make sure it works,

glxgears

Next, install WMware Player, then download and install VMware Tools for the guest OS. This can be done when running the Windows in the VM, by clicking “Virtual Machine” > “Install VMware Tools…”. Alternatively, we can download all VMware Tools for all the supported OSes from Player Preferences menu item. After finish downloading, we can run the setup in the Windows just like VirtualBox. The installation of VMware Tools allows seamless integration of the host and the guest like VirtualBox: such as resizing the window will resize the Windows resolution directly, and also the seamless mouse integration.

After installation, make sure 3D acceleration is enabled. This can be done from VMX file or from the Virtual Machine Settings,

mks.enable3d = "TRUE"
svga.graphicsMemoryKB = "1000000"

If 3D acceleration still does not work, then in the ~/.vmware/preferences, add

mks.gl.allowBlacklistedDrivers = "TRUE"

Next, in the ~/.vmware/preferences, add followings

pref.motionUngrab = "FALSE"
pref.motionGrab = "FALSE"

This disable auto grabbing or ungrabbing our mouse pointer when it moves into the VM window.

However, in my case, my 3D game is very sensitive to the mouse movement. Thus, I have to disable the drivers installed by the VMware Tools. This can be done through Device Manager in Windows. After disabling the drivers, my mouse cannot click anything in VM. I have to use keyboard to restart the Windows.

 

Finally, I think I can enjoy more games in Linux now, though playing the games virtually in Windows.

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Installing games with CD iso images and change disc in WINE


Previously I mentioned about playing games in WINE and enabling Ibus input and CJK fonts. Recently, I solved another problem, that is installing the game with ISO images.

We know that, in Linux, we can mount the ISO image easily. However, some old games will need to install with several discs, that means we need to change discs during the installation. When my disc 1 was completed, I tried to unmount, it failed. Even I tried with symlink, the disc 2 with the symlink is not detected by the installer, failed also.

The solution is actually simple.

  1. Firstly, run the winecfg.
  2. Go to Drives tab.
  3. Click Show Advanced button.
  4. Click Add…, for example, add a D: drive.
  5. Now, we can Browse… the path of our mounted ISO images.
  6. The important part is the Type:, we need to change to CD-ROM.
  7. Apply.

Now, in the WINE, there is a new CD-ROM drive. We can change the CD-ROM to any Linux file system path. So, mount the disc 1, run the installer.exe in the D:, complete disc 1, the installer will ask for disc 2. In the winecfg, change the D: path to mounted disc 2, apply. Go back to the installer, the disc 2 should be detected.

Enjoy the games.

(This is tested with SimCity 4 Deluxe.)

Android game hacking


[Added 2012-10-16] Read this first: Quite a lot of readers asked me how to hack this game or hack that game. Sorry to say, I am not that expert in hacking those games, and I don’t have much time to play and hack the games. And what I shared here is only how to hack the games in general way, without permanent root the Android. So, if you are asking about a specific game, please find it on other channel. Thank you.

Frustrated with some Android games? Want to hack? Want to kill the monsters with one slice?

Okay, this is the main purpose I learn about Android rooting. After we gain the “#” from “adb shell” (refers to my previous post), now we can see all the files in /data folder. This folder contains the game save data and also some libraries.

Simple problem and solution

My hacking method is not memory editing, but save file editing. So, to edit the save file, we must have the knowledge and experience on hexadecimal editing. Now, since we can access those data files in /data/data folder, meaning that we can pull them, edit them, push them back.

So, pull the save file you want, the name such as Save0.dat or similar name. Use a hex editor, such as bless, ghex, hexedit, etc. Edit the value, then push the file back.

I personally wrote a small command-line tool, so that I can do hex editing in adb shell. (It is available here). I push it to /data/local/tmp folder, so that I can use it without pulling and pushing the file.

For some games, the save file is plain binary file. We can understand the file with the hex editing, such as the value of the coins, the level of the weapons, the status of the hero such as strength, vital, hp, and so on. These can be easily edited. (Please always make a backup before editing).

Advanced problem and solution

For other games, the save file is really a pain. They are encrypted/encoded save file. We cannot understand anything about the file. Modifying the file does not help. So, my only solution is to edit the library file, i.e. shared object (.so).

For example, if there is a library called libdhunter.so, we need to use objdump (ARM target, not x86 or x86-64 target) to disassemble the shared object. The objdump can be obtained from Android NDK package.

/path-to/objdump -dC libdhunter.so > asm.txt #pull the library file first, not doing this in adb shell

This will create “asm.txt” which contains the disassembled data. Now, what we can do is just study the functions. We might find some functions such as “encode”, “encrypt”, “decode”, “decrypt”, “save”, “load”. And also, need to look for open file, read or write file, and close file. This is because normally, they will call encrypt or encode before write the file (save). Study what the functions they are calling.

For example, in the “save” function, it might contain a call of “encode” function, then only “write” the buffer. In this case, it will be quite easy to solve the problem. Use a hex editor to open the shared object. Edit the hexadecimal value of the opcode that calls the “encode” function within “save” to “00 00 00 00”, this will produce NOP operation. That means, we disable calling “encode” function in “save” function.

Then, we can objdump again to check whether we have disabled the function call.

Push the edited library to the device. Make sure backup the original library and also the save file.

Run the game, load the save file, save the game, then exit.

Now, do not restart the game yet. Now, check the newly saved file with hex editor. If it is a plain binary file, then we success! If not, try until you want to give up.

Do not restart the game yet, because the game will load the encoded save file, not the plain binary save file. So, to make the game load the plain binary save file, we need to disable calling “decode” function in the “load” function as the method discussed above.

Push the newly edited library, then start the game.

Now, we can hex edit the save file freely as we like.

Other problem and solution (added 2012-03-19)

There are even easier problems, such as the game Aqua Pet. There is no shared object (lib*.so). And the save file is also a plain text file. Meaning, we need no hex editor to edit it. However, editing the file might not change anything. In this type of case, we must “force stop” the app first, then edit the file.

Now, enjoy the games.

Playing games with Ubuntu


Linux is a great OS. Open source and free. Can work as server or desktop. There are a lot of applications: office suite, internet web browser, email client, image editor, 3D modeler, games, online games, software development tools, etc. Using Linux, I can almost do anything I want just as I am using proprietary OS.

However, there is a drawback. If a computer cannot be used for playing games, then it will not be 100% perfect. Yes, Linux has a lot of free and open source games, but I feel that there is still a gap between free games and the commercial games. Though I may not use Linux to play the latest game, at least it should allow me to play my favourite game.

Luckily there is WINE. Though it cannot 100% compatible to all the games, at least have a try. The following is a screenshot of my most favourite game!

Taikou Risshiden 5
Taikou Risshiden 5 using WINE