Mesa 21.1.2 builds with Visual Studio and MSYS2 Mingw-w64 are now available in releases section.
opengl32.dllfrom MinGW package depends on Vulkan runtime since 21.0.0
This is an upstream regression introduced when zink driver was patched to support Windows.
This is not a defect but rather a behavior change of Mesa when environment variables are misconfigured. It usually happens when selecting a Mesa driver that doesn't exist in release package used or it fails to initialize due to host system not meeting hardware requirements or lacking dependencies. Reading differences between MSVC and MinGW packages and Mingw and MSVC Package contents should aid in troubleshooting.
You may experience them with programs that use any Mesa3D desktop OpenGL driver via per app deployment tool, system wide deployment is unaffected. You may experience them if per app deployment was done before shared glapi support was introduced. shared glapi has been consistently available in both MSVC and MinGW packages since 20.0.2.
To correct these errors regardless of cause you have to re-deploy. If you don't remember if an affected program is 32-bit or 64-bit, right click on opengl32.dll shortcut in the folder where the program executable is located and select open file location. If location ends in x64 then it's 64-bit, otherwise it's 32-bit.
Same problem with same solution applies to osmesa if you are upgrading from 188.8.131.521-1 or older.
If you need to migrate from Mingw to MSVC binaries you just need to replace Mesa binaries folder from Mingw package with MSVC counterpart.
The following Mesa3D drivers and build artifacts are shipped in each release:
opengl32.dll. When it's not the default driver select it by setting environment variable
opengl32.dll. Select it by setting environment variable
opengl32.dlland standalone as
openglon12.dlland it's only available in MSVC package. In addition to officially requiring Windows 10 v10.0.19041.488 or newer, it also depends on DirectX IL for redistribution -
dxil.dllto load, which can be installed via deployment tools. When available and if it can load, this is the default Mesa3D desktop OpenGL driver on D3D12 GPU accelerated systems. This driver introduced in 21.0.0 is operating as wrapper returning D3D12 API calls. Due to this nature it can use GPU accelleration. If it's not selected by default you can test it with Direct3D WARP software renderer built into Windows by setting
LIBGL_ALWAYS_SOFTWARE=1environment variables. The standalone copy doesn't need
GALLIUM_DRIVER=d3d12being set and it can only be installed via system-wide deployment tool. The standalone GLonD3D12 and Mesa3D Desktop OpenGL bundle replace each other when using system-wide deployment tool but you can reverse it any time.
opengl32.dlland it's only available in MinGW package. Siimilarly to GLonD3D12, it operates as wrapper returning Vulkan API calls. Due to this nature it uses GPU accelleration. Select it via
GALLIUM_DRIVER=zinkenvironment variable, but note that it requires at least 1 Vulkan device and Vulkan loader/runtime to initialize. zink ignores Vulkan CPU type devices by default but you can test it with them by also setting
opengl32.dllit still depends on it. This alternative desktop OpenGL software rendering driver developed by Intel is optimized for visualization software. It's available in MSVC package and since 20.1.7 in MinGW package as well. It only supports x64, x86 is officially unsupported. There are currently 4 DLLs, only one being loaded based on what the user CPU can do. You can switch to swr by setting GALLIUM_DRIVER environment variable value to swr.
Build instructions, if you want to replicate my builds, are available here.
First choose between Mingw and MSVC package. See About Mingw package section for details. Before extracting release package close all programs that use Mesa if any is running. After extraction you will have access to 2 deployment options, both located in the directory you installed Mesa. Both deployment utilities have a start-over mechanism so you can do all deployments you need in one session.
Examples on OpenGL context configuration override, switch to swr driver and old applications compatibility are available here.
Old applications from early 200x and older may need MESA_EXTENSION_MAX_YEAR environment variable set to avoid buffer overflows. It expects a year number as value, most commonly used being 2001. It trims the extensions list returned by Mesa3D to extensions released up to and including provided year as Mesa3D extensions list is sorted by year.
set MESA_EXTENSION_MAX_YEAR=2001. See How to set environment variables.
With release of OpenGL 3.1 many features marked as deprecated in OpenGL 3.0 have been removed and since OpenGL 3.2 launch this OpenGL specification branch is known as OpenGL core profile. Also in OpenGL 3.3 a new branch of the OpenGL specification known as forward compatible context was introduced which removes the OpenGL 3.0 deprecated features that were not removed in OpenGL 3.1. Most proprietary drivers implemented the exemptions from these changes offered in the form of GL_ARB_compatibility extension for OpenGL 3.1 and compatibility contexts for OpenGL 3.2 and above. Due to complexity and especially lack of correct implementation tests for GL_ARB_compatibility and compatibility contexts, Mesa3D developers chose to retain features deprecated in OpenGL 3.0 and implement core profile and forward compatible contexts. Mesa 18.1 introduced GL_ARB_compatibility support making the first step toward having compatibility contexts support in the future. Because GL_ARB_compatibility is only for OpenGL 3.1, programs requesting OpenGL compatibility context won't get above OpenGL 3.0 for Mesa 18.0 and 3.1 for Mesa 18.1 and newer. Unfortunately these kind of programs are prevalent on Windows where developers tend to avoid using context flags required by core profile. Fortunately Mesa3D provides a mechanism to override the OpenGL context requested. There are 2 environment variables that override OpenGL context configuration:
It is used to specify OpenGL context version and type. It expects a value in the following format
FC means a forward compatible context. COMPAT means a compatibility context for OpenGL 3.2 and newer and GL_ARB_compatibility being enabled for OpenGL 3.1. Absence of any string after version number means the Mesa3D default context type for OpenGL version specified which is as follows: deprecated features enabled for OpenGL 3.0, GL_ARB_compatibility enabled for OpenGL 3.1 since Mesa 18.1 and core profile for OpenGL 3.2 and above. Examples: 3.3FC means OpenGL 3.3 forward compatible context, 3.1COMPAT means OpenGL 3.1 with GL_ARB_compatibility , 3.2 means OpenGL 3.2 core profile. The default value is 3.1COMPAT for Mesa 18.1 and 3.0COMPAT for Mesa 18.0.
A very important feature provided by this variable is the possibility to configure an incomplete OpenGL context. Programs can only request up to the highest OpenGL context with Khronos certification as complete from Mesa3D driver in use. Currently llvmpipe is certified for OpenGL 4.5 in core profile / forward compatible context and 3.1 in compatibility profile. Currently swr is certified for OpenGL 3.3 in core profile / forward compatible context and 3.1 in compatibility profile. Since Mesa 17.3 values meant for OpenGL 4.6 are recognized.
Used to specify shading language version. Supported values are version numbers converted to integer: 110, 120, 130, 140. 150, 330, 400, 410, 420, 430, 440, 450 and 460. Value 460 is only recognized since Mesa 17.3. Value 130 for example matches GLSL 1.30. It is always a good idea to keep OpenGL context and shading language versions in sync to avoid programs confusion which may result in crashes or glitches. This can happen because most applications rely on proprietary drivers behavior of having OpenGL and GLSL versions in sync. Here is the OpenGL - GLSL correlation table. Default values: 140 for Mesa 18.1 and 130 for Mesa 18.0 if MESA_GL_VERSION_OVERRIDE is undefined or 330 otherwise.
Under Windows the easiest way to set environment variables is by writing batch files. You'll most likely need to do so:
Simply open Notepad, write the batch script. When saving, end the file name with .bat or .cmd, change save as type to all files and change save location to where the application executable is located. If you have some skill with batch scripts you can change the current directory during script execution using CD command opening the possibility to save the script anywhere you want as shown in rpcs3 and GPU Caps Viewer examples. Documentation of most environment variables used by Mesa is available here. Complete examples are available here.
You can set multiple environment variables on same batch script to mix the functionality provided by Mesa3D.