Real-time rendering is a critical aspect of many modern applications, including video games, simulations, and virtual reality experiences. Ensuring smooth and responsive visuals in real-time requires efficient multithreading.

In C++, the Standard Library provides several threading options, including std::thread and std::async. However, with the introduction of C++20, a new addition to the threading library called std::jthread was introduced. In this blog post, we will explore how to leverage std::jthread for real-time rendering.

What is std::jthread?

std::jthread is a thread-aware RAII (Resource Acquisition Is Initialization) wrapper introduced in C++20. It provides an easy and safe way to create and manage threads by encapsulating both the thread and its associated joinable state.

Using std::jthread for Real-Time Rendering

To illustrate the usage of std::jthread in real-time rendering, let’s consider a simple example where we want to render a scene in parallel while continuously updating it. We’ll assume we have a Renderer class that handles rendering and an Updater class that updates the scene data.

class Renderer {
public:
    void render() {
        // Rendering implementation
    }
};

class Updater {
public:
    void update() {
        // Scene update implementation
    }
};

Now, we can create a render loop that utilizes std::jthread to perform rendering and updating in parallel:

#include <chrono>
#include <iostream>
#include <thread>

int main() {
    Renderer renderer;
    Updater updater;

    std::jthread renderThread([&]() {
        while (true) {
            renderer.render();
            std::this_thread::sleep_for(std::chrono::milliseconds(16)); // Render at ~60 FPS
        }
    });

    std::jthread updateThread([&]() {
        while (true) {
            updater.update();
            std::this_thread::sleep_for(std::chrono::milliseconds(33)); // Update at ~30 FPS
        }
    });

    // Wait for user input to exit the application
    std::cin.get();
    return 0;
}

In the example above, we create two std::jthread objects, renderThread and updateThread, which encapsulate the rendering and updating tasks, respectively. The threads execute their respective tasks in an infinite loop, with appropriate sleep durations to achieve the desired frame rates.

Benefits of std::jthread

Using std::jthread for real-time rendering offers several benefits:

1. Automatic Resource Management: std::jthread automatically joins the thread upon destruction, ensuring proper resource management without the need for manual join or detach calls.
2. Exception Safety: std::jthread handles exceptions thrown from the associated thread and ensures proper cleanup, avoiding resource leaks.
3. Thread Interruption: std::jthread provides a convenient request_stop() member function, allowing safe interruption of the associated thread.

Conclusion

std::jthread is a valuable addition to the C++ threading library, especially for real-time rendering scenarios. It simplifies thread management, ensuring resource safety and exception handling. By leveraging std::jthread, developers can create responsive and parallel rendering systems that meet the demands of modern applications.

#RealTimeRendering #Multithreading