feat(sdk/cpp): Add vision sample, auto-download NuGet deps, and SDK README

[apsonawane]

feat(sdk/cpp): Add Responses API vision sample with auto-download build system

Adds a C++ vision sample, NuGet auto-download build infrastructure, SDK README, and find_package(FoundryLocal) support

What's included

Vision sample (sdk/cpp/sample/web-server-responses-vision/)

• Demonstrates vision (image understanding) using the Foundry Local web service and the OpenAI Responses API
• Loads, resizes (max 512px), and base64-encodes images using stb
• Streams model response token-by-token via SSE using libcurl
• Robust SSE parsing with persistent buffer across cURL callbacks
• Mirrors the structure of samples/python/web-server-responses-vision

SDK build improvements (sdk/cpp/CMakeLists.txt)

• Auto-downloads NuGet runtime DLLs (Core, OnnxRuntime, OnnxRuntimeGenAI) at configure time via fl_ensure_nuget_package()
• Exposes fl_copy_runtime_dlls(TARGET) — copies all runtime DLLs next to any executable
• Vision sample built as optional target WebServerResponsesVision (requires curl)
• CMake install rules for producing a redistributable SDK layout

find_package(FoundryLocal) support (sdk/cpp/cmake/FoundryLocalConfig.cmake)

• Consumers can use the prebuilt SDK via find_package(FoundryLocal REQUIRED)
• Provides imported target FoundryLocal::FoundryLocal and fl_copy_runtime_dlls() helper

SDK README (sdk/cpp/README.md)

• Full documentation: features, prerequisites, build steps, quick start, API usage examples
• Vision sample build instructions (from SDK root and standalone)
• Prebuilt SDK zip creation and consumer workflow
• Configuration reference, API reference, troubleshooting

Files changed (13 files, +1129 lines)

File	Change
sdk/cpp/CMakeLists.txt	NuGet auto-download, fl_copy_runtime_dlls(), vision sample target, install rules
sdk/cpp/README.md	Full SDK documentation (new)
sdk/cpp/cmake/FoundryLocalConfig.cmake	find_package(FoundryLocal) support (new)
sdk/cpp/vcpkg.json	Added curl, stb dependencies
sdk/cpp/test/model_variant_test.cpp	Fixed test: Download callback returns bool not void
sdk/cpp/sample/web-server-responses-vision/main.cpp	Vision sample implementation (new)
sdk/cpp/sample/web-server-responses-vision/stb_impl.cpp	stb library implementation (new)
sdk/cpp/sample/web-server-responses-vision/CMakeLists.txt	Sample build config (new)
sdk/cpp/sample/web-server-responses-vision/CMakePresets.json	Standalone build presets (new)
sdk/cpp/sample/web-server-responses-vision/README.md	Sample documentation (new)
sdk/cpp/sample/web-server-responses-vision/test_image.jpg	Default test image (new)
sdk/cpp/sample/web-server-responses-vision/vcpkg.json	Sample vcpkg manifest (new)
sdk/cpp/sample/web-server-responses-vision/vcpkg-configuration.json	vcpkg baseline (new)

Build & run

# From sdk/cpp (builds everything)
cmake --preset x64-debug
cmake --build --preset x64-debug --target WebServerResponsesVision
.\out\build\x64-debug\WebServerResponsesVision.exe qwen3.5-0.8b

# Or standalone from the sample directory
cd sample/web-server-responses-vision
cmake --preset x64-debug
cmake --build --preset x64-debug
.\out\build\x64-debug\web-server-responses-vision.exe qwen3.5-0.8b

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
foundry-local	Ready	Preview, Comment	May 7, 2026 10:58pm

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds a new Windows-focused C++ sample that calls a local Foundry web service using the /v1/responses endpoint for vision + SSE streaming, including build plumbing via CMake/vcpkg and stb-based image preprocessing.

Changes:

• Introduces a C++ vision streaming sample using libcurl (SSE) and stb (load/resize/JPEG/base64).
• Adds vcpkg manifest + baseline configuration for sample dependencies.
• Adds CMake project wiring that builds the Foundry Local C++ SDK as a subdirectory and links WinML EP Catalog libs.

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
samples/cpp/web-server-responses-vision/main.cpp	Implements image preprocessing, SSE parsing/streaming via libcurl, and Foundry Local web service orchestration.
samples/cpp/web-server-responses-vision/stb_impl.cpp	Provides single TU stb implementations for image load/resize/write used by the sample.
samples/cpp/web-server-responses-vision/CMakeLists.txt	Adds a standalone build for the sample and links to the Foundry SDK, curl, and WinML deps.
samples/cpp/web-server-responses-vision/vcpkg.json	Declares vcpkg dependencies needed by the sample.
samples/cpp/web-server-responses-vision/vcpkg-configuration.json	Pins a vcpkg builtin registry baseline for reproducible builds.
samples/cpp/web-server-responses-vision/README.md	Documents prerequisites, build/run steps, and a high-level flow explanation.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 12 out of 13 changed files in this pull request and generated 10 comments.

[Copilot]

Pull request overview

Copilot reviewed 12 out of 13 changed files in this pull request and generated 3 comments.