OpenGl程序 - 仅显示黑屏

Question

我尝试使用简单的openGl程序绘制三角形，我只能在窗口看到黑屏。

以下是供您参考的代码。

让我知道我做错了什么。

// Headers
#include <GL/glew.h>
#include <GL/glut.h>//Drawing funciton
#include <GL/freeglut.h>
// Link statically with GLEW
#define GLEW_STATIC

// Shader sources
const GLchar* vertexSource =
    "##version 300 es\n"
    "in vec2 position;"
    "void main()"
    "{"
    "    gl_Position = vec4(position, 0.0, 1.0);"
    "}";
const GLchar* fragmentSource =
    "##version 300 es\n"
    "out vec4 outColor;"
    "void main()"
    "{"
    "    outColor = vec4(1.0, 1.0, 1.0, 1.0);"
    "}";

int main(int argc,char**argv)
{    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);
    glutInitWindowSize(800,600);
    glutCreateWindow("GW");
    //glutSetOption(GLUT_ACTION_ON_WINDOW_CLOSE,GLUT_ACTION_GLUTMAINLOOP_RETURNS);

    // Initialize GLEW
    glewExperimental = GL_TRUE;
    glewInit();

    // Create Vertex Array Object
    GLuint vao;
    glGenVertexArrays(1, &vao);
    glBindVertexArray(vao);

    // Create a Vertex Buffer Object and copy the vertex data to it
    GLuint vbo;
    glGenBuffers(1, &vbo);

    GLfloat vertices[] = {
         0.0f,  0.5f,
         0.5f, -0.5f,
        -0.5f, -0.5f
    };

    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    // Create and compile the vertex shader
    GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexSource, NULL);
    glCompileShader(vertexShader);

    // Create and compile the fragment shader
    GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentSource, NULL);
    glCompileShader(fragmentShader);

    // Link the vertex and fragment shader into a shader program
    GLuint shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glBindFragDataLocation(shaderProgram, 0, "outColor");
    glLinkProgram(shaderProgram);
    glUseProgram(shaderProgram);

    // Specify the layout of the vertex data
    GLint posAttrib = glGetAttribLocation(shaderProgram, "position");
    glEnableVertexAttribArray(posAttrib);
    glVertexAttribPointer(posAttrib, 2, GL_FLOAT, GL_FALSE, 0, 0);

    bool running = true;
    while (running)
    {
        // Clear the screen to black
        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        // Draw a triangle from the 3 vertices
        glDrawArrays(GL_TRIANGLES, 0, 3);

        // Swap buffers
        glutSwapBuffers();
    }

    glDeleteProgram(shaderProgram);
    glDeleteShader(fragmentShader);
    glDeleteShader(vertexShader);

    glDeleteBuffers(1, &vbo);

    glDeleteVertexArrays(1, &vao);

    return 0;
}