VBO 和 VAO 不绘制 opengl 和 LWJGL3

Question

我已经玩了一段时间的 open GL，我已经到了可以绘制 3d 形状的地步，我的形状、顶点和索引绝对是正确的，我的形状变得一团糟。我现在想重做我的画。我以前只使用没有 VAO 的 VBO，只是绑定和绘制它们。这有效，但我怀疑这是我的错误。所以我开始使用 VAO，我没有看到我的代码有任何问题，我仍然无法让它绘制我的白色方块（没有着色器，就像 wiki 教程一样）。

我的窗口初始化代码在这里：

private void initWindow() {
    //Makes sure window can work
    if (!glfwInit()) {
        throw new IllegalStateException("Failed to Initialize GLFW!");
    }

    //Create window object and set its hints
    glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE);

    this.windowRef = glfwCreateWindow(width, height, name, NULL, NULL);

    if (windowRef == 0) {
        throw new IllegalStateException("Failed to create Window!");
    }

    GLFWVidMode videoMode = glfwGetVideoMode(glfwGetPrimaryMonitor());
    glfwSetWindowPos(windowRef, (videoMode.width() - width) / 2, (videoMode.height() - height) / 2);

    // Make the OpenGL context current
    glfwMakeContextCurrent(windowRef);
    // Enable v-sync
    glfwSwapInterval(1);

    //Make GL capabilites for window
    GL.createCapabilities();
    glfwShowWindow(windowRef);
}

我的缓冲区和对象初始化代码在这里

public void loadGL() {
    float[] vertex = {
        0f, 0f, 0f, //0
        0.5f, 0, 0, //1
        0.5f, 0, 0.5f, //2
        0f, 0f, 0.5f, //3
        0f, 0.5f, 0f, //4
        0.5f, 0.5f, 0, //5
        0.5f, 0.5f, 0.5f,//6
        0f, 0.5f, 0.5f//7
    };

    int[] index = {
        0, 1, 2, //0
        0, 2, 3, //1
        0, 3, 4, //2
        3, 7, 4,//3
        0, 4, 1,//4
        1, 5, 4,//5
        1, 5, 2,//6
        2, 6, 5,//7
        2, 3, 6,//8
        3, 7, 6,//9
        4, 5, 7,//10
        5, 6, 7//11
    };
    size = 12*3;

    indicesBuff = BufferUtils.createIntBuffer(index.length);
    vertBuff = BufferUtils.createFloatBuffer(vertex.length);
    indicesBuff.put(index);
    vertBuff.put(vertex);
    indicesBuff.flip();
    vertBuff.flip();

    vao = glGenVertexArrays();
    glBindVertexArray(vao);

    vboID = glGenBuffers();
    glBindBuffer(GL_ARRAY_BUFFER, vboID);
    glBufferData(GL_ARRAY_BUFFER, vertBuff, GL_STATIC_DRAW);
    GL20.glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, 0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);

    ibo = glGenBuffers();
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, indicesBuff, GL_STATIC_DRAW);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
    glBindVertexArray(0);

}

最后我的主循环就到这里了，在窗口初始化之后调用：

    private void mainLoop() {
    loadGL();
    glClearColor(0.5f, 0.5f, 0.5f, 1);
    while (!glfwWindowShouldClose(windowRef)) {

        //Render Stuff here
        //TODO: later skip this block if nothing has changed
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // clear 
the framebuffer

        glBindVertexArray(vao);
        glEnableVertexAttribArray(0);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);

        glDrawElements(GL_TRIANGLES, size, GL_UNSIGNED_INT, 0);

//            glBegin(GL_QUADS);
//            glVertex3f(-0.5f, -0.5f, 0);
//            glVertex3f(-0.5f, 0.5f, 0);
//            glVertex3f(0.5f, -0.5f, 0);
//            glVertex3f(0.5f, 0.5f, 0);
//            glEnd();

        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
        glDisableVertexAttribArray(0);
        glBindVertexArray(0);

        glfwSwapBuffers(windowRef);
        glfwPollEvents();
    }
}

顺便说一句，用 glBegin 绘制它，这样可以，但它对我想做的事情效率不高。

Answer 1

在 OpenGL 中呈现的现代方式是使用Shader 程序。

如果您不使用着色器程序，则必须使用glVertexPointer 不推荐的方式定义顶点数据数组，并且您必须通过glEnableClientState( GL_VERTEX_ARRAY ) 启用顶点坐标的客户端功能：

vao = glGenVertexArrays();
glBindVertexArray(vao);

vboID = glGenBuffers();
glBindBuffer(GL_ARRAY_BUFFER, vboID);
glBufferData(GL_ARRAY_BUFFER, vertBuff, GL_STATIC_DRAW);
GL20.glVertexPointer(3, GL_FLOAT, 0, 0);  // <--------------
glBindBuffer(GL_ARRAY_BUFFER, 0);

 glBindVertexArray(vao);
 glEnableClientState( GL_VERTEX_ARRAY );   // <--------------
 glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);

 glDrawElements(GL_TRIANGLES, size, GL_UNSIGNED_INT, 0);

 glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
 glDisableClientState( GL_VERTEX_ARRAY ); // <---------------
 glBindVertexArray(0);

---

进一步注意，客户端功能（或顶点属性数组）的状态和对索引（元素）缓冲区的引用存储在Vertex Array Objects 状态向量中。 因此，在指定顶点数组对象时启用顶点坐标并在绑定顶点数组对象时投标索引缓冲区就足够了。绘制几何图形时，顶点坐标的启用和禁用以及索引缓冲区的绑定可以省略：

vao = glGenVertexArrays();
glBindVertexArray(vao);

vboID = glGenBuffers();
glBindBuffer(GL_ARRAY_BUFFER, vboID);
glBufferData(GL_ARRAY_BUFFER, vertBuff, GL_STATIC_DRAW);
GL20.glVertexPointer(3, GL_FLOAT, 0, 0);    // <--------------
glEnableClientState( GL_VERTEX_ARRAY );     // <--------------
glBindBuffer(GL_ARRAY_BUFFER, 0);

ibo = glGenBuffers();
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, indicesBuff, GL_STATIC_DRAW);
// skip glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
glBindVertexArray(0);

glBindVertexArray(vao);

glDrawElements(GL_TRIANGLES, size, GL_UNSIGNED_INT, 0);

glBindVertexArray(0);