Updating display driver breaks texture system.

[AStar8]

Hello! I'm a games developer and developing a new game with Unity. As part of the game we have developed a system which generates horses from a few textures in many different ways.

A couple of weeks back a few testers reported that they were experiencing some weird looking textures being created by the system. Unable to find or even recreate the bug, I eventually bought the exact model of laptop they use (a Lenovo G50 with Intel HD 5500 graphics)

Today the laptop has arrived - I turned it on, checked the dxdiag information and believe the default driver installed was one from 2015. Ran the game, and everything ran perfectly, unexpected as I bought this laptop just to recreate the bug.

However I then updated the driver to the latest version available (from November last year). And now the textures look completely bizarre when being created. There is no transparency maintained between the textures and coloring effects do not work properly.

On the left in the image below is how this one horse looked before updating the display drivers, on the right is how it looks after updating the display drivers.

All that is being done to create the final texture is:

- Create a render texture (Final Result Texture)

- For each input bitmap (all 512x512 fairly uninteresting bitmap)

A) If necessary for this part, invert any of the RGBA channels specified

B) Apply contrast to the output of A

C) Apply hue and lightness changes to output of B

D) Import the alpha channel from the original bitmap to the output of C

E) Blit D to the final result texture

Any ideas what is going on here? Should I just tell my users to rollback to a much earlier version of the driver?

I should add that the system works fine on every other thing its been tested on, Android, Apple, Nvidia, ATI etc

[AStar8]

To add more detail to this, this is an example of a wrong looking horse when the Intel driver is installed, it's failed to do pretty much anything asked of it by the shaders in the texture system

I couldn't find the version of the driver originally installed on my laptop so I removed all drivers to see if it would then work:

This is how this particular horse should look (and how it looks on every other chipset). At the moment I'm not too sure what to tell my users if the game ends up going live with no fix available as it works on everything else other than an intel chipset.

[idata]

Hello Andrew2110:

Thank you very much for providing those details and the pictures. Just to let you know, we recommend to use the driver provided by the manufacturer since the Intel graphics drivers are generic and they might or might not work with your system. I was looking for the graphics drivers on Lenovo's web site but there are many results showing under Lenovo G50, did you tried those drivers? http://support.lenovo.com/us/en/ http://support.lenovo.com/us/en/ On the following link you will find all the graphics drivers for Intel® HD 5500 graphics, you mentioned that the one that belongs to 2015 works fine, but there might a newer driver that works as good: https://downloadcenter.intel.com/product/86210/Intel-HD-Graphics-5500 https://downloadcenter.intel.com/product/86210/Intel-HD-Graphics-5500 Now, at this point, we can try to replicate the issue in our lab, is there any way that we can get your game in order for us to do that? Besides that, there is some information that we need and you can find on the following link: /thread/77761 https://communities.intel.com/thread/77761 Any further questions, please let me know. Regards Alberto

[AStar8]

I really appreciate the reply, thank you! I think it might be best if I spend a few hours tonight / tomorrow morning creating a minimal project to recreate the issue and provide source code an executable for you to use as sending the few gb's in my git repo would be a nightmare to play with! I shall go through every driver available to that laptop to see if I can pinpoint one that works for us, tomorrow morning I'll provide some source code / a project to recreate the issue (might be able to do a WebGL one if thats preferred so no executables are being linked to here)

[idata]

Hello Andrew2110:

You are welcome. Perfect, we understand and once you get the chance to post the results of your investigation please do that, since I am pretty sure that information will be really helpful for all the peers viewing the thread. Any questions, please let me know. Regards Alberto

[AStar8]

Thank you, I found a part of code which seemed to be where the graphics card had issues,

the bitmaps when overlayed with one another can have a number of blend modes (think photoshop) applied to them. When the blend mode was set to "normal" thats when the Intel chip would take issue. I looked further into this and it seems that importing the alpha channel of the bitmap when blend mode was normal was causing this behaviour and as the shader used to blit this bitmap maintains transparency anyways importing the alpha channel was unnecessary anyways so could be removed and now it all works perfectly!

So in short, there was some strange behaviour, but have found a way to fix the code so as to avoid this behaviour and unless other people report some strange texture issues I don't think it's worth investigating further?

Thanks so much for the quick and professional response though.