Graphics Card Influencing Whether OpenGL Project Runs

Summary: If you're sure your OpenGL program has no bugs, code-wise, and it's still crashing, it may be your graphics card can't handle the program. In that case, if you have switchable graphics, try switching the graphics card assigned to run the program. Switching from x64 build to x86 could work, but I think that could still lead to random crashes. The "switchable graphics" option works more consistently, I think.

Or maybe upgrade the graphics card. I don't have experience with that though, so I can't say for sure. Though that'd definitely would cost a lot. Or maybe it's a driver bug, which sucks too.

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I mentioned about a High Performance power setting option in my last post. Wanted to go more into that today.

When I did the Multiple Lights tutorial on Learn OpenGL maybe a long time ago, I was pretty sure I got no errors, code wise. However, when I ran the program, it crashed. This was on a x64 Release build of the project.

I was really sure the code had no errors. I admit I was just copy n pasting code haha. Though I was just learning OpenGL for the first time. I still am new to GL right now as I'm writing it. (As long as the code works, even with copy n paste, I'm still happy with it. I'll go back to it one day and look at it more.)

I tried to run it in Debug mode in VS 2015, got this:

Even odder. When I first saw it, I found 'ig7icd64.dll' to be an interesting file. I found that in C:\Windows\System32. (Now even that's odder! I remember figuring that out for the first time, that 64-bit applications ran using dlls from the System32 folder, while 32-bit apps ran using the SysWOW64 folder. That took a long time to figure out, was a nightmare haha. I think this msdn link and stack overflow link explain what's going on well.)

I remember I even tried to look for files with the same name in other directories in my computer, and I even tried to download a .dll of the same name somewhere. I tried to temporarily replace the .dll, but nothing worked. I got other errors. So I replaced the original .dll.


Anyways, this was really puzzling me. If I remember right, back then, I also tried to mess around with the fragment shader. I found that there was a threshold to the amount of light struct objects I could instantiate in the shader. So for example, given the struct:

struct PointLight {
    vec3 position;
   
    float constant;
    float linear;
    float quadratic;

    vec3 ambient;
    vec3 diffuse;
    vec3 specular;
};

If I was to make an array of maybe like 4 to 7 of these struct objects, the program would crash. Like it was just a one-liner like "PointLight array[3];" in the shader's main() function. However, if I instantiated a single struct object, it wouldn't crash. I'm still not sure about the reasoning behind this. I did some searching on that, and I think what I found was that the members of the struct object are like uniform variables, and the graphics card has a max amount of uniform variables allowed when running with OpenGL. 

This was still super confusing. The most interesting part is that I tried it in my dorm-mate's computer, same 64-bit build .exe, and it worked on his. And I tried it on a university library computer, and it worked on that one too! (Ironically, it didn't work on a computer in the student center computer lab lol. If I remember right, it wasn't even the same error, like some glfw error.) 

Side note:

I used VS 2015 to make these builds. I found out I had to make sure to include any image files and shader files in the same directory as my .exe. I also had to include the correct .dlls. In general, I found you need these .dlls with your .exe:

64-bit build Release:

C:\Windows\System32\msvcp140.dll

C:\Windows\System32\vcruntime140.dll

64-bit build Debug:

C:\Windows\System32\msvcp140d.dll

C:\Windows\System32\vcruntime140d.dll

32-bit build Release:

C:\Windows\SysWOW64\msvcp140.dll

C:\Windows\SysWOW64\vcruntime140.dll

32-bit build Debug:

C:\Windows\SysWOW64\msvcp140d.dll

C:\Windows\SysWOW64\vcruntime140d.dll

Anyways, jeez, so I realized that it was something to do with my laptop. I was pretty bummed out at first. (I can't upgrade/change graphics cards in my laptop. They're like "integrated" into the laptop.) 

After more thought, though, I found out that my laptop has switchable graphics. When I right click in my desktop, I got this:

Here's the window that comes up afterwards:

Lol I never knew I had this before, even the fact that I had 2 graphics card in my laptop. When I first saw it, the Graphics Setting was at "Not Assigned". When I changed it to Power Saving, clicked Apply, and tried running it again, it crashed. So I assumed "Not Assigned" led to the Power Saving option at the time, even though I'm pretty sure my laptop was plugged in at the time. However, when I changed it to High Performance, it ran, the 64-bit build Release! I was so happy! : )

It ran on my desktop, ran from the USB, it was awesome. Looking back at the Device Manager and Display adapters section, I know now I have 2 graphics card. I'm pretty sure, when talking about the switchable graphics program above, that they correspond like this:

Power saving: Intel(R) HD Graphics 4000

High performance: AMD Radeon HD 7570M/HD 7670M Graphics

So ya, that was it. I always have that .exe set to "High performance". That was quite the interesting time figuring that out, especially the fact that my laptop had 2 graphics cards. Didn't even think of the idea before haha.