Initial Decart C++ SDK

[AdirAmsalem]

Decart C++ SDK 🎉

This adds a first-class C++ SDK so native apps, desktop tools, robotics, and game/engine integrations can use Decart's realtime models directly — no browser or Python runtime required. It rounds out our SDK lineup with the same concepts and ergonomics developers already know, in idiomatic, modern C++.

What you can do

• Transform video in realtime — stream frames to a model and get the transformed frames back, and steer the look live with prompts and reference images.
• Authenticate — mint short-lived client tokens from a server-side API key.

Usage

#include <decart/decart.h>
#include <livekit/livekit.h>

decart::Client client;                                   // reads DECART_API_KEY
auto model  = decart::models::realtime("lucy-2.1");
auto source = std::make_shared<livekit::VideoSource>(model.width, model.height);

decart::ConnectOptions opts;
opts.model = model;
opts.initialState.prompt = decart::Prompt{"put them all in space"};
opts.onRemoteFrame = [](const livekit::VideoFrame& frame, std::int64_t) {
  // render / encode the transformed frame
};

auto session = client.realtime().connect(source, opts);
// ... push your camera/render frames into `source` ...
session->setPrompt("a watercolor painting");   // change the look on the fly
session->disconnect();

// Auth: short-lived client token for untrusted clients
auto token = client.tokens().create();

Notes

• Easy to adopt: pulls its dependencies automatically via CMake (works with or without vcpkg), ships runnable examples (including streaming a video file through a model and saving the result), unit tests, and CI for Linux, macOS, and Windows.
• Lightweight option: an auth/tokens-only build is available for backends that only mint tokens and don't need the realtime stack.
• Verified end-to-end against production for both token creation and a full video transform.

Scope is intentionally minimal for this first release (realtime + auth); more surfaces can follow.