GLFW 创建多端口

Question

我想在window上创建两个视口，但是只有一个可以运行移动效果，另一个是停止，

我很困惑，当我设置两个相同的对象时，仍然有一个端口可以运行移动效果，另一个端口停止，但是当我删除一个着色器对象时，两个视口都可以显示由另一个着色器对象生成的相同移动效果。

这是我的代码：

int main()
{
    // glfw: initialize and configure
    // ------------------------------
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

#ifdef __APPLE__
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif

    // glfw window creation
    // --------------------
    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
    if (window == NULL)
    {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);



    //glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);


    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }


    glEnable(GL_DEPTH_TEST);


    Shader ourShader("../../shader/vertex.glsl", "../../shader/cloud_frag.glsl");

    

    float vertices[] = {
        // positions          // colors           // texture coords
         1.0f,  1.0f, 0.0f,   1.0f, 0.0f, 0.0f,   1.0f, 1.0f, // top right
         1.0, -1.0f, 0.0f,   0.0f, 1.0f, 0.0f,   1.0f, 0.0f, // bottom right
        -1.0f, -1.0f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f, // bottom left
        -1.0f,  1.0f, 0.0f,   1.0f, 1.0f, 0.0f,   0.0f, 1.0f  // top left 
    };

    unsigned int indices[] = {
        0, 1, 3, // first triangle
        1, 2, 3  // second triangle
    };

    unsigned int VBO, VAO, EBO;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);
    glGenBuffers(1, &EBO);
    glBindVertexArray(VAO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
    // position attribute
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);
    // color attribute
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
    glEnableVertexAttribArray(1);
    // texture coord attribute
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
    glEnableVertexAttribArray(2);


    Shader ourShader1("../../shader/vertex1.glsl", "../../shader/cloud2_frag.glsl");
    float vertices1[] = {
        // positions          // colors           // texture coords
         1.0f,  1.0f, 0.0f,   1.0f, 0.0f, 0.0f,   1.0f, 1.0f, // top right
         1.0, -1.0f, 0.0f,   0.0f, 1.0f, 0.0f,   1.0f, 0.0f, // bottom right
        -1.0f, -1.0f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f, // bottom left
        -1.0f,  1.0f, 0.0f,   1.0f, 1.0f, 0.0f,   0.0f, 1.0f  // top left 
    };

    unsigned int indices1[] = {
        0, 1, 3, // first triangle
        1, 2, 3  // second triangle
    };
    unsigned int VBO1, VAO1, EBO1;
    glGenVertexArrays(1, &VAO1);
    glGenBuffers(1, &VBO1);
    glGenBuffers(1, &EBO1);
    glBindVertexArray(VAO1);
    glBindBuffer(GL_ARRAY_BUFFER, VBO1);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices1), vertices1, GL_STATIC_DRAW);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO1);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices1), indices1, GL_STATIC_DRAW);
    // position attribute
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);
    // color attribute
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
    glEnableVertexAttribArray(1);
    // texture coord attribute
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
    glEnableVertexAttribArray(2);


    unsigned int texture1 = loadtexture("F:/Project/opengl/shadertoy/iChannels/RGBA_noise_medium.png");

    ourShader.use();
    ourShader.setInt("iChannel0", 0);           //iChannel0 is texture and has been binded, the 0 is texture unit, not texture ID
    //ourShader.setInt("texture2", 1);
    ourShader1.use();
    ourShader1.setInt("iChannel0", 0);
    //resolution_width = 100;
    //resolution_height = 200;
    //glViewport(20, 20, 100, 200);
    // render loop
    // -----------
    while (!glfwWindowShouldClose(window))
    {
        // per-frame time logic
        // --------------------
        float currentFrame = glfwGetTime();
        deltaTime = currentFrame - lastFrame;
        lastFrame = currentFrame;

        ourShader.setFloat("iTime", currentFrame);
        ourShader.setVec3("iResolution", resolution_width, resolution_height, 0.0);

        ourShader1.setFloat("iTime", currentFrame);
        ourShader1.setVec3("iResolution", resolution_width, resolution_height, 0.0);
        // input
        // -----
        processInput(window);

        // render
        // ------
        glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        // activate shader
        ourShader.use();
        glViewport(10, 10, 200, 200);
        glBindVertexArray(VAO);
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
        
        ourShader1.use();
        glViewport(300, 300, 200, 200);
        glBindVertexArray(VAO1);
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

        // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
        // -------------------------------------------------------------------------------
        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    glDeleteVertexArrays(1, &VAO1);
    glDeleteBuffers(1, &VBO1);
    // glfw: terminate, clearing all previously allocated GLFW resources.
    // ------------------------------------------------------------------
    glfwTerminate();
    return 0;
}

Answer 1

glUniform* specify a value of a uniform variable for the currently installed program object. Hence you've to install the program before setting the uniforms (glUseProgram):

ourShader.use();
ourShader.setFloat("iTime", currentFrame);
ourShader.setVec3("iResolution", resolution_width, resolution_height, 0.0);

ourShader1.use();
ourShader1.setFloat("iTime", currentFrame);
ourShader1.setVec3("iResolution", resolution_width, resolution_height, 0.0);

GLFW 创建多端口

GLFW create multiport

c++

opengl

glsl

glfw

opengl-es-3.0