Question

我在Ubuntu 14.04上使用GPU Nvidia Titan X（驱动程序版本375.66）以相同的刷新率使用两个具有不同原始分辨率的显示器。我想在第二台显示器上实时显示捕获的图像全屏，同时在主显示器上操作相机GUI。

使用glfw和OpenGL的最低复制次数为：

#include <stdio.h>
#include <stdlib.h>
#include <glad/glad.h>
#include <GLFW/glfw3.h>

GLFWwindow* open_window(const char* title, GLFWmonitor* monitor)
{
    const GLFWvidmode* mode = glfwGetVideoMode(monitor);

    glfwWindowHint(GLFW_RED_BITS, mode->redBits);
    glfwWindowHint(GLFW_GREEN_BITS, mode->greenBits);
    glfwWindowHint(GLFW_BLUE_BITS, mode->blueBits);

    GLFWwindow* window = glfwCreateWindow(mode->width, mode->height, title, monitor, NULL);
    if (!window)
        return NULL;

    glfwMakeContextCurrent(window);
    gladLoadGLLoader((GLADloadproc) glfwGetProcAddress);

    glfwSwapInterval(1);
    glfwShowWindow(window);

    return window;
}

GLuint create_texture(GLFWmonitor* monitor)
{
    const GLFWvidmode* mode = glfwGetVideoMode(monitor);
    int width  = mode->width;
    int hieght = mode->height;

    char pixels[width * hieght];
    GLuint texture;

    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);

    for (int y = 0;  y < hieght;  y++)
        for (int x = 0;  x < width;  x++)
            pixels[y * width + x] = rand() % width;

    glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, width, hieght, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, pixels);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

    return texture;
}

void draw_quad(GLuint texture)
{
    int width, height;
    glfwGetFramebufferSize(glfwGetCurrentContext(), &width, &height);

    glViewport(0, 0, width, height);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(0.f, 1.f, 0.f, 1.f, 0.f, 1.f);

    glEnable(GL_TEXTURE_2D);
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

    glBegin(GL_QUADS);

    glTexCoord2f(0.f, 0.f);
    glVertex2f(0.f, 0.f);

    glTexCoord2f(1.f, 0.f);
    glVertex2f(1.f, 0.f);

    glTexCoord2f(1.f, 1.f);
    glVertex2f(1.f, 1.f);

    glTexCoord2f(0.f, 1.f);
    glVertex2f(0.f, 1.f);

    glEnd();
}

int main(int argc, char** argv)
{
    if (!glfwInit())
        exit(EXIT_FAILURE);

    // detect and print monitor information
    int monitor_count;
    GLFWmonitor** monitors = glfwGetMonitors(&monitor_count);
    printf("Number of monitors detected: %d\n", monitor_count);
    if (monitor_count < 2)
    {
        printf("The second monitor is not connected.\n");
        return false;
    }

    // open a window fullscreen on second monitor
    GLFWwindow *window = open_window("Captured image", monitors[1]);
    if (!window)
    {
        glfwTerminate();
        exit(EXIT_FAILURE);
    }

    // the loop
    while (!glfwWindowShouldClose(window))
    {
        // create the image (say, the captured image via camera App)
        GLuint texture = create_texture(monitors[1]);

        // show the image
        draw_quad(texture);
        glfwSwapBuffers(window);
    }

    glfwTerminate();
    exit(EXIT_SUCCESS);
}

问题是，当我将当前焦点切换到相机GUI或终端时，Ubuntu的标题栏会出现。例如： 顶部：专注于窗口（全屏完美）。下图：关注终端;注意现在出现不需要的顶部标题栏（标记为红色）。

X将两个显示器视为一个大屏幕，因此屏幕截图中有额外的黑色像素：

我发现https://bugs.launchpad.net/unity/+bug/853865表示第二个显示屏上的顶部面板无法隐藏，并被视为Unity的待实现功能。

如何在glfw内克服此问题？如果没有，任何其他OpenGL框架替代建议？我想保持多平台。

在Ubuntu 14.04上使用OpenGL在第二台显示器上始终全屏

0 个答案: