Jul 21, 2020 07:00:00

When a certain game is played on an AMD-equipped PC, a bug that the character turns black is discovered, a correction patch by volunteers is being distributed

Games that can be played on PCs are evolving day by day, and if you select hardware with a higher-performance

CPU or GPU , game play will become more comfortable. However, when I played the game on a high-performance PC, I encountered an unexpected bug, game developer Adrian publishes the cause of the bug and the patch to fix on his blog.

Fixing Mass Effect black blobs on modern AMD CPUs | Silent's Blog
https://cookieplmonster.github.io/2020/07/19/silentpatch-mass-effect/

The TPS game ' Mass Effect ', which fights against aliens as a representative of humankind with the mission of protecting all life in the universe, is a game characterized by a precise and realistic space civilization, and the Windows version was released in 2008. According to Adrian, when the Windows version of Mass Effect was played on a PC equipped with AMD FX and Ryzen , there was a problem on the Internet that 'a problem occurs where the character turns black'. However, it seems that it was possible to play without problems on AMD-equipped PCs prior to AMD FX.

Below is the screen that played Mass Effect with no bugs occurring. A character operated by the player is displayed in the center, but...

When I play Mass Effect on an AMD-equipped PC, the character turns black as shown below. The contour resolution is also coarse and obviously unnatural.

Although there is no problem with the text at the top of the screen, the map at the bottom right, the background, etc., all characters other than the characters operated by the player are also black.

Mr. Adrian also played Mass Effect on a PC equipped with an Intel CPU, but he said that the same bug did not occur. However, when

PIX on Windows which is a debugging tool of DirectX is used and the capture of the Direct3D command acquired on the Intel-equipped PC is opened on the AMD-equipped PC, a bug has been confirmed. From this, Adrian pointed out, 'I suggest that this bug is caused by the CPU, not the GPU, and is due to the difference in the commands executed on AMD and Intel.'

Mr. Adrian found that there was a problem with the character's lighting calculation when he proceeded with the investigation because there was a problem with the character's drawing process. When I checked what the calculated value was, AMD's calculated value showed NaN value. In fact, AMD CPUs once supported an extended instruction set called 3DNow!. However, in 2010, we announced the end of support for 3DNow!, and AMD FX and Ryzen are not compatible with 3DNow!. As a result, it seems that an error occurred when the 2008 game was optimized for AMD FX and Ryzen, and the lighting calculation result became an incorrect value.

Adrian has created a patch to solve the Mass Effect lighting problem on AMD CPUs and has posted it on his website.

Mass Effect | Silent's Blog
https://cookieplmonster.github.io/mods/mass-effect/#silentpatch

The following is before using the patch.

The following is after using the patch. Characters are now clearly drawn.

Mr. Adrian has published the code of the created patch on GitHub, and you can check it from the following URL. In addition, this time Adrian discovered a defect in Mass Effect, but it is unknown whether the same bug will occur when playing other games on a PC equipped with AMD FX and Ryzen.

GitHub-CookiePLMonster/SilentPatchME: SilentPatch for Mass Effect, fixing black blob artifacts on AMD CPUs
https://github.com/CookiePLMonster/SilentPatchME