48 lines
2.2 KiB
Markdown
48 lines
2.2 KiB
Markdown
---
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title: OpenGL in a virtual machine
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date: 2019-06-12 18:30:00
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---
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As I prefer to work on a Linux computer for programming, at work I have to
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use a virtual machine to execute the product and test in a real environment
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using different Windows versions.
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The problem encountered is that the emulated graphics card, even with full
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drivers in my KVM setup is only providing an OpenGL 1.1 version, something
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so old that some of the functionalities of our application are not working
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and display black boxes instead.
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After trying to install additional drivers or setup a more complete emulation,
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a newer emulated card or other complex steps, I found a simpler way : Using
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a Mesa3D driver with the llvmpipe that will emulate the lastest OpenGL features
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using what is available on the emulated machine. The result will not be fast
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enough for a 3D game for example, but every feature will become available.
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You can download an already compiled distribution of the Mesa3D sources at
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https://github.com/pal1000/mesa-dist-win/releases. By default, I download
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the msvc version as I usually have everything needed. Once downloaded, simply
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extract the archive in your download or Desktop folder.
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I usually install the library System-Wide, as a replacement to the Microsoft
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OpenGL software renderer that only support the very old OpenGL 1.1 version.
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Select the first option to install the LLVM pipe System-Wide so that any
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application needing OpenGL will use the Mesa3D implementation instead of the
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Microsoft renderer without any further configuration needed.
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Once installed System-Wide, you can simply restart your application and
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check that the available OpenGL version has been bumped to a default 3.1
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version. This default version can be overridden by setting the `MESA_GL_VERSION_OVERRIDE`
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environment variable. For example, if you want to get OpenGL 4.6, you can
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create a `MyApplication.cmd` that will launch the executable :
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```
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@set MESA_GL_VERSION_OVERRIDE=4.6COMPAT
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@MyApplication.exe
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```
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It is important to note that profiles higher than the default can be incomplete and
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are not certified as a full implementation. If your application only uses
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extensions that are implemented, this will work but YMMV.
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