chore: import upstream snapshot with attribution

examples/cpp/clock/main.cpp

@@ -0,0 +1,56 @@
+#include <rerun.hpp>
+
+#include <algorithm> // std::max
+#include <cmath>
+#include <string>
+
+using namespace std::chrono;
+
+constexpr float TAU = 6.28318530717958647692528676655900577f;
+
+void log_hand(
+    const rerun::RecordingStream& rec, const char* name, seconds step, float angle, float length,
+    float width, uint8_t blue
+) {
+    const auto tip = rerun::Vec3D{length * sinf(angle * TAU), length * cosf(angle * TAU), 0.0f};
+    const auto c = static_cast<uint8_t>(angle * 255.0f);
+    const auto color =
+        rerun::Color{static_cast<uint8_t>(255 - c), c, blue, std::max<uint8_t>(128, blue)};
+
+    rec.set_time_duration("sim_time", step);
+
+    rec.log(
+        std::string("world/") + name + "_pt",
+        rerun::Points3D(rerun::Position3D(tip)).with_colors(color)
+    );
+    rec.log(
+        std::string("world/") + name + "hand",
+        rerun::Arrows3D::from_vectors(rerun::Vector3D(tip))
+            .with_origins({{0.0f, 0.0f, 0.0f}})
+            .with_colors(color)
+            .with_radii({width * 0.5f})
+    );
+}
+
+int main() {
+    const float LENGTH_S = 20.0f;
+    const float LENGTH_M = 10.0f;
+    const float LENGTH_H = 4.0f;
+    const float WIDTH_S = 0.25f;
+    const float WIDTH_M = 0.4f;
+    const float WIDTH_H = 0.6f;
+
+    const int num_steps = 10000;
+
+    const auto rec = rerun::RecordingStream("rerun_example_clock");
+    rec.spawn().exit_on_failure();
+
+    rec.log_static("world", rerun::ViewCoordinates::RIGHT_HAND_Y_UP);
+    rec.log_static("world/frame", rerun::Boxes3D::from_half_sizes({{LENGTH_S, LENGTH_S, 1.0f}}));
+
+    for (int step = 0; step < num_steps; step++) {
+        log_hand(rec, "seconds", seconds(step), (step % 60) / 60.0f, LENGTH_S, WIDTH_S, 0);
+        log_hand(rec, "minutes", seconds(step), (step % 3600) / 3600.0f, LENGTH_M, WIDTH_M, 128);
+        log_hand(rec, "hours", seconds(step), (step % 43200) / 43200.0f, LENGTH_H, WIDTH_H, 255);
+    }
+}