Function find_instance_at

examples/main_video.cpp:277–288

Check if a click position lands on any tracked instance mask. Returns the instance_id or -1.

// Check if a click position lands on any tracked instance mask.
// Returns the instance_id or -1.
static int find_instance_at(const vapp_state& app, float ix, float iy) {
    int px = (int)ix, py = (int)iy;
    for (const auto& det : app.result.detections) {
        if (det.mask.data.empty()) continue;
        if (px >= 0 && px < det.mask.width &&
            py >= 0 && py < det.mask.height &&
            det.mask.data[py * det.mask.width + px] > 127) {
            return det.instance_id;
        }
    }
    return -1;
}

static void add_instance_from_prompts(vapp_state& app) {
    if (!app.tracker_created || !app.frame_encoded) return;