improve image creation tests and windows opengl ci

.github/workflows/opengl-test-windows.yml

@@ -31,22 +31,30 @@ jobs:
     - name: Checkout repository
       uses: actions/checkout@v4
 
-    - name: Download Mesa
-      run: |
-        curl -LO https://github.com/pal1000/mesa-dist-win/releases/download/23.3.1/mesa3d-23.3.1-release-msvc.7z
-        7z x mesa3d-23.3.1-release-msvc.7z -omesa
+    - name: Install 7zip
+      run: choco install -y 7zip
 
-    - name: Set Mesa in PATH
-      run: echo "$env:GITHUB_WORKSPACE\\mesa\\x64" | Out-File -Append -FilePath $env:GITHUB_PATH    
-
-    - name: Set Mesa env
+    - name: Download Mesa (prebuilt, MSVC x64)
+      shell: pwsh
       run: |
-        echo "LIBGL_ALWAYS_SOFTWARE=1" >> $env:GITHUB_ENV
-        echo "MESA_GL_VERSION_OVERRIDE=4.3" >> $env:GITHUB_ENV
-        echo "MESA_GLES_VERSION_OVERRIDE=3.2" >> $env:GITHUB_ENV
-        echo "LIBGL_DEBUG=verbose" >> $env:GITHUB_ENV
-        echo "EGL_LOG_LEVEL=debug" >> $env:GITHUB_ENV
-        echo "MESA_VERBOSE=all" >> $env:GITHUB_ENV
+        $ver = "24.3.4"
+        $uri = "https://github.com/pal1000/mesa-dist-win/releases/download/$ver/mesa3d-$ver-release-msvc.7z"
+        Invoke-WebRequest $uri -OutFile "$env:RUNNER_TEMP\mesa.7z"
+        7z x "$env:RUNNER_TEMP\mesa.7z" "-o$env:RUNNER_TEMP\mesa" -y
+
+    - name: Drop Mesa next to the exe (EGL headless)
+      shell: pwsh
+      run: |
+        $dll_dir = "$env:RUNNER_TEMP\mesa\x64"
+        Copy-Item "$dll_dir\opengl32.dll"      -Destination "build\Release"
+        Copy-Item "$dll_dir\libgallium_wgl.dll" -Destination "build\Release"
+        Copy-Item "$dll_dir\libEGL.dll"        -Destination "build\Release"
+        # If you use OSMesa (Mesa < 25.1): also copy osmesa.dll
+
+    - name: Force llvmpipe + core 4.5
+      run: |
+        setx GALLIUM_DRIVER llvmpipe
+        setx MESA_GL_VERSION_OVERRIDE 4.5
 
     # Force xmake to a specific folder (for cache)
     - name: Set xmake env