Linux画像素缓冲区 [英] Linux draw pixel buffer

问题描述

问题很简单，我有一个生成像素缓冲区的代码.现在，我需要呈现此像素缓冲区，而不是保存图像，然后再对其进行分析.

The problem is simple enough, i have a code that generates a pixel buffer. Now i need to present this pixel buffer instead of saving image and then analyzing it after.

解决方案是什么?

1. 打开窗口
2. 用我的像素RGB888替换此窗口中的所有像素

到目前为止，建议是:若要使用opengl，请为覆盖窗口的矩形创建顶点缓冲区，然后使用像素着色器绘制像素.显然，这不是在窗口中交换像素缓冲区的最佳方法.

So far suggestion were: To use opengl, create a vertex buffer for a rect covering a window, and use pixel shader to draw your pixels. Which clearly is not the best way to swap pixel buffers in window.

平台:Ubuntu 18

Platform: Ubuntu 18

推荐答案

您还可以使用 SFML .实际上，在我的其他答案中，它似乎比 CImg 快得多.我不是这方面的专家，但是以下代码可以满足您的需求:

You can also display bitmapped images in a window pretty easily with SFML. In fact, it seems considerably faster than CImg in my other answer. I am no expert in this, but the following code does what you seem to want:

// g++ -std=c++11 main.cpp $(pkg-config --libs --cflags sfml-graphics sfml-window)

#include <SFML/Graphics.hpp>
#include <iostream>
#include <cstdint>

int main()
{
    const unsigned width = 1024;
    const unsigned height= 768;

    // create the window
    sf::RenderWindow window(sf::VideoMode(width, height), "Some Funky Title");

    // create a texture
    sf::Texture texture;
    texture.create(width, height);

    // Create a pixel buffer to fill with RGBA data
    unsigned char *pixbuff = new unsigned char[width * height * 4];
    // Create uint32_t pointer to above for easy access as RGBA
    uint32_t * intptr = (uint32_t *)pixbuff;

    // The colour we will fill the window with
    unsigned char red  = 0;
    unsigned char blue = 255;

    // run the program as long as the window is open
    int frame = 0;
    while (window.isOpen())
    {
        // check all the window's events that were triggered since the last iteration of the loop
        sf::Event event;
        while (window.pollEvent(event))
        {
            // "close requested" event: we close the window
            if (event.type == sf::Event::Closed)
                window.close();
        }

        // clear the window with black color
        window.clear(sf::Color::Black);

        // Create RGBA value to fill screen with.
        // Increment red and decrement blue on each cycle. Leave green=0, and make opaque
        uint32_t RGBA;
        RGBA = (red++ << 24) | (blue-- << 16) | 255;
        // Stuff data into buffer
        for(int i=0;i<width*height;i++){
           intptr[i] = RGBA;
        }
        // Update screen
        texture.update(pixbuff);
        sf::Sprite sprite(texture);
        window.draw(sprite);

        // end the current frame
        window.display();
        std::cout << "Frame: " << frame << std::endl;
        frame++;
        if(frame==1000)break;
    }

    return 0;
}

在Mac上，我达到了以下帧速率:

On my Mac, I achieved the following frame rates:

• 700 fps @ 640x480分辨率
• 384 fps @ 1024x768分辨率

如果您想提高性能，则可以/可以在第二个线程外创建并填充屏幕外的纹理，但这已经非常快了.

You can/could create and fill a texture off-screen in a second thread if you want to improve performance, but this is already pretty fast.

关键字:C ++，图像处理，显示，位图图形，像素缓冲区，SFML，imshow，质数.

Keywords: C++, Image Processing, display, bitmapped graphics, pixel buffer, SFML, imshow, prime.

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