VAO不渲染

Question

我创建了一个加载器类，用于加载V.A.Os纹理等，但是当我使用此方法时

GLuint Loader::loadToVAO(GLfloat* vertices)
{
    GLuint VertexArrayID;
    glGenVertexArrays(1, &VertexArrayID);
    glBindVertexArray(VertexArrayID);

    GLuint vertexbuffer;
    glGenBuffers(1, &vertexbuffer);
    glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    return vertexbuffer;
}

它没有渲染任何东西--这里是我的呈现代码：

window.createWindow();

GLfloat vertices[] = {
    -1.0f, -1.0f, 0.0f,
    1.0f, -1.0f, 0.0f,
    0.0f,  1.0f, 0.0f,
};

GLuint vertexbuffer = loader.loadToVAO(vertices);

glClearColor(0, 1, 1, 0);

// It works fine when i generate the vao in the main method but not in the loader class
GLuint vertexbuffer1;
glGenBuffers(1, &vertexbuffer1);
glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer1);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

std::cout << vertexbuffer1 << std::endl;
std::cout << vertexbuffer << std::endl;

while (!window.shouldClose())
{
    window.clearWindow();

    // render here
    glEnableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer1);
    glVertexAttribPointer(
        0,                  // attribute 0. No particular reason for 0, but must match the layout in the shader.
        3,                  // size
        GL_FLOAT,           // type
        GL_FALSE,           // normalized?
        0,                  // stride
        (void*)0            // array buffer offset
    );
    // Draw the triangle !
    glDrawArrays(GL_TRIANGLES, 0, 3); // Starting from vertex 0; 3 vertices total -> 1 triangle
    glDisableVertexAttribArray(0);

    window.updateWindow();
}

return 0;

当我尝试呈现vertexbuffer1 (加载在main方法中的那个)时，它呈现得很好，但是顶点缓冲区没有呈现任何内容。如能提供任何帮助，将不胜感激。

编辑：这里是我试图遵循的教程- http://www.opengl-tutorial.org/

Answer 1

在函数中的指针类型上使用sizeof，这几乎肯定不是您想要的。在C和C++等语言中，数组不是C++，它们会衰减为指针，这些指针不携带关于它们存储的数据量的信息。相反，您要做的是将数组的大小作为附加参数传递：

GLuint Loader::loadToVAO(GLfloat* vertices, size_t num_vertices)
{
    GLuint VertexArrayID;
    glGenVertexArrays(1, &VertexArrayID);
    glBindVertexArray(VertexArrayID);

    GLuint vertexbuffer;
    glGenBuffers(1, &vertexbuffer);
    glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(*vertices) * num_vertices, vertices, 
    GL_STATIC_DRAW);
    return vertexbuffer;
}

然后在你的主要功能中：

GLuint vertexbuffer = loader.loadToVAO(vertices, sizeof(vertices) / sizeof(vertices[0]));

我鼓励你多读一些关于这里主题的文章。