[build] Add VS Code integration

* Infer the VCPKG triplet for MSVC-like environments.
* Add recommended VS Code settings.
* Add instructions for using clangd.

.gitignore

@@ -5,7 +5,11 @@
 *.so
 *.dll
 *.exe
-.vscode
+.vscode/
+
+# clangd files
+compile_commands.json
+.cache/
 
 # vim swap files
 *.sw?

README.md

@@ -6,6 +6,8 @@
   - [Building](#building)
   - [Building a Libretro core](#building-a-libretro-core)
   - [Visual Studio Support](#visual-studio-support)
+  - [Visual Studio Code Support](#visual-studio-code-support)
+    - [Optional: clangd](#optional-clangd)
   - [Dependencies](#dependencies)
   - [Cross compiling for 32 bit on a 64 bit host](#cross-compiling-for-32-bit-on-a-64-bit-host)
   - [Cross Compiling for Win32](#cross-compiling-for-win32)
@@ -109,6 +111,37 @@ cmake .. -DVCPKG_TARGET_TRIPLET=x64-windows-static -DCMAKE_BUILD_TYPE=Debug -G N
 ninja
 ```
 
+## Visual Studio Code Support
+
+On most platforms, Visual Studio Code should work as-is, as long as the
+[CMake Tools extension](https://marketplace.visualstudio.com/items?itemName=ms-vscode.cmake-tools)
+is installed.
+
+There is a recommended configuration in the `vscode/settings.json` file. To use
+it, copy the file to a `.vscode/` folder.
+
+By default, this will publish builds in the `build-vscode/` directory. In the
+`vscode/settings.json` file, there is an alternate configuration for the
+`"cmake.buildDirectory"` option that will use different build directories for
+different toolchains and build configurations.
+
+### Optional: clangd
+
+The [clangd extension](https://marketplace.visualstudio.com/items?itemName=llvm-vs-code-extensions.vscode-clangd)
+uses clangd to provide powerful code completion, errors and warnings and
+references on click in VS Code.
+
+With the recommended configuration, the build configuration will generate a
+`compile_commands.json` file that can be used with clangd. After configuration,
+you can copy that file to the root directory with a command similar to this one:
+
+```shell
+cp build/build-vscode/compile_commands.json .
+```
+
+Then, select "clangd: Restart language server" from the command palette to get
+completion in the IDE.
+
 ## Dependencies
 
 If your OS is not supported, you will need the following:

cmake-variants.yaml

@@ -0,0 +1,23 @@
+buildType:
+  default: debug
+  choices:
+    debug:
+      short: Debug
+      long: Emit debug information
+      buildType: Debug
+    release:
+      short: Release
+      long: Optimize generated code
+      buildType: Release
+
+linkage:
+  default: static
+  choices:
+    static:
+      short: Static
+      long: Create static libraries
+      linkage: static
+    shared:
+      short: Shared
+      long: Create shared libraries/DLLs
+      linkage: shared

cmake/Set-Toolchain-vcpkg.cmake

@@ -3,7 +3,49 @@ if(POLICY CMP0012)
 endif()
 
 if(NOT DEFINED VCPKG_TARGET_TRIPLET)
+    # Check if we are in an MSVC environment.
+    if($ENV{CXX} MATCHES "cl.exe$")
+        # Infer the architecture from the LIB folders.
+        foreach(LIB $ENV{LIB})
+            if(${LIB} MATCHES "x64$")
+                set(VBAM_VCPKG_PLATFORM "x64-windows")
+                break()
+            endif()
+            if(${LIB} MATCHES "x86$")
+                set(VBAM_VCPKG_PLATFORM "x86-windows")
+                break()
+            endif()
+            if(${LIB} MATCHES "ARM64$")
+                set(VBAM_VCPKG_PLATFORM "arm64-windows")
+                break()
+            endif()
+        endforeach()
+
+        # If all else fails, try to use a sensible default.
+        if(NOT DEFINED VBAM_VCPKG_PLATFORM)
+            set(VBAM_VCPKG_PLATFORM "x64-windows")
+        endif()
+
+    elseif (NOT DEFINED CMAKE_CXX_COMPILER)
+        # No way to infer the compiler.
         return()
+
+    elseif(${CMAKE_CXX_COMPILER} MATCHES "clang-cl.exe$" OR ${CMAKE_CXX_COMPILER} MATCHES "clang-cl$")
+        # For stand-alone clang-cl, assume x64.
+        set(VBAM_VCPKG_PLATFORM "x64-windows")
+    endif()
+
+    if (NOT DEFINED VBAM_VCPKG_PLATFORM)
+        # Probably not an MSVC environment.
+        return()
+    endif()
+
+    if(DEFINED BUILD_SHARED_LIBS AND NOT ${BUILD_SHARED_LIBS})
+        set(VBAM_VCPKG_PLATFORM ${VBAM_VCPKG_PLATFORM}-static)
+    endif()
+
+    set(VCPKG_TARGET_TRIPLET ${VBAM_VCPKG_PLATFORM} CACHE STRING "Vcpkg target triplet (ex. x86-windows)" FORCE)
+    message(STATUS "Inferred VCPKG_TARGET_TRIPLET=${VCPKG_TARGET_TRIPLET}")
 endif()
 
 function(vcpkg_seconds)

vscode/settings.json

@@ -0,0 +1,9 @@
+{
+    "cmake.generator": "Ninja",
+    "cmake.configureSettings": {
+        "CMAKE_EXPORT_COMPILE_COMMANDS": "ON",
+    },
+    "cmake.buildDirectory": "${workspaceRoot}/build-vscode",
+    // To use separate directories for different configurations:
+    // "cmake.buildDirectory": "${workspaceRoot}/build/${buildKitTriple}-${buildKitVersion}/${variant:buildType}-${variant:linkage}",
+}