Use a cache in GitHub workflow instead of downloading Vulkan SDK with every CI run

Author: IAmNotHanni

.github/workflows/linux.yaml

@@ -29,20 +29,27 @@ jobs:
         ${{matrix.install}}
         cmake -E make_directory ${{runner.workspace}}/build
 
+    - name: Cache Vulkan SDK
+      id: cache-vulkan
+      uses: actions/cache@v4
+      with:
+        path: vulkan_sdk
+        key: vulkan-sdk-1.4.309.0
+
     - name: Prepare Vulkan SDK
       shell: bash
       run: |
-        curl -LS -o vulkansdk.tar.xz https://sdk.lunarg.com/sdk/download/1.4.309.0/linux/vulkansdk-linux-x86_64-1.4.309.0.tar.xz
-        mkdir -p vulkan_sdk
-        tar xf vulkansdk.tar.xz -C vulkan_sdk
-        rm -rf vulkansdk.tar.xz
-        
-        export VULKAN_SDK=$GITHUB_WORKSPACE/vulkan_sdk/1.4.309.0/x86_64
-        export PATH=$VULKAN_SDK/bin:$PATH
-        export LD_LIBRARY_PATH=$VULKAN_SDK/lib:$LD_LIBRARY_PATH
-        export VK_ICD_FILENAMES=$VULKAN_SDK/etc/vulkan/icd.d
-        export VK_LAYER_PATH=$VULKAN_SDK/etc/vulkan/layer.d
+        if [ ! -d "vulkan_sdk/1.4.309.0/x86_64" ]; then
+          echo "Vulkan SDK not found in cache. Downloading..."
+          curl -LS -o vulkansdk.tar.xz https://sdk.lunarg.com/sdk/download/1.4.309.0/linux/vulkansdk-linux-x86_64-1.4.309.0.tar.xz
+          mkdir -p vulkan_sdk
+          tar xf vulkansdk.tar.xz -C vulkan_sdk
+          rm -f vulkansdk.tar.xz
+        else
+          echo "Using cached Vulkan SDK"
+        fi
 
+        export VULKAN_SDK=$GITHUB_WORKSPACE/vulkan_sdk/1.4.309.0/x86_64
         echo "VULKAN_SDK=$VULKAN_SDK" >> $GITHUB_ENV
         echo "PATH=$VULKAN_SDK/bin:$PATH" >> $GITHUB_ENV
         echo "LD_LIBRARY_PATH=$VULKAN_SDK/lib:$LD_LIBRARY_PATH" >> $GITHUB_ENV