在GLFW的OpenGL中没有绘制三角形

Question

我在tutorial中做了所有事情，但没有显示三角形。本教程是针对Windows完成的，但我使用的是Mavericks。谁能告诉我代码中有什么问题？

#include "GL/glew.h"
#define GLFW_DLL
#include "GLFW/glfw3.h"
#include <iostream>

int main( void )
{
    if (!glfwInit()) {
        fprintf(stderr, "ERROR: could not start GLFW3\n");
        return 1;
    }

    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    GLFWwindow* window = glfwCreateWindow(640, 480, "Hello Triangle", NULL, NULL);
    if (!window) {
        fprintf(stderr, "ERROR: could not open window with GLFW3\n");
        glfwTerminate();
        return 1;
    }
    glfwMakeContextCurrent (window);

    glewExperimental = GL_TRUE;
    glewInit ();

    const GLubyte* renderer = glGetString(GL_RENDERER);
    const GLubyte* version = glGetString(GL_VERSION);
    printf("Renderer: %s\n", renderer);
    printf("OpenGL version supported %s\n", version);

    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);

    float points[] = {
        0.0f,  0.5f,  0.0f,
        0.5f, -0.5f,  0.0f,
        -0.5f, -0.5f,  0.0f
    };

    GLuint vbo = 0;
    glGenBuffers(1, &vbo);
    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glBufferData(GL_ARRAY_BUFFER, 9 * sizeof(float), points, GL_STATIC_DRAW);

    GLuint vao = 0;
//  glGenVertexArrays(1, &vao);
    glGenVertexArraysAPPLE(1, &vao);
    glBindVertexArray(vao);
    glEnableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);

    const char* vertex_shader =
        "#version 400\n"
        "in vec3 vp;"
        "void main () {"
        "  gl_Position = vec4 (vp, 1.0);"
        "}";

    const char* fragment_shader =
        "#version 400\n"
        "out vec4 frag_colour;"
        "void main () {"
        "  frag_colour = vec4 (0.5, 0.0, 0.5, 1.0);"
        "}";

    GLuint vs = 0;
    glShaderSource(vs, 1, &vertex_shader, NULL);
    glCompileShader(vs);

    GLuint fs = 0;
    glShaderSource(fs, 1, &fragment_shader, NULL);
    glCompileShader(fs);

    GLuint shader_programme = glCreateProgram();
    glAttachShader(shader_programme, vs);
    glAttachShader(shader_programme, fs);
    glLinkProgram(shader_programme);

    while (!glfwWindowShouldClose(window)) {
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glUseProgram(shader_programme);
//      glBindVertexArray(vao);
        glBindVertexArrayAPPLE(vao);
        glDrawArrays(GL_TRIANGLES, 0, 3);
        glfwPollEvents();
        glfwSwapBuffers(window);
    }

    glfwTerminate();
    return 0;
}

printf()和glGetString(GL_RENDERER)的

glGetString(GL_VERSION)方法在输出中显示以下内容：

Renderer: NVIDIA GeForce GT 750M OpenGL Engine
OpenGL version supported 4.1 NVIDIA-8.26.28 310.40.55b01