test.cpp

// Link statically with GLEW
#define GLEW_STATIC

// Headers
#include <SFML/Window.hpp>
#include <SFML/Graphics.hpp>
#include <GL/glew.h>
#include <iostream>

// Shader sources
const GLchar* vertexSource =
    "#version 150 core\n"
    "in vec2 position;"
    "void main() {"
    "   gl_Position = vec4(position, 0.0, 1.0);"
    "}";
const GLchar* fragmentSource =
    "#version 150 core\n"
    "out vec4 outColor;"
    "void main() {"
    "   outColor = vec4(1.0, 1.0, 1.0, 1.0);"
    "}";

int main()
{
    sf::ContextSettings settings;
    settings.depthBits = 24;
    settings.stencilBits = 8;

    sf::Window window(sf::VideoMode(800, 600, 32), "OpenGL", sf::Style::Titlebar | sf::Style::Close, settings);

    // 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)
    {
        sf::Event windowEvent;
        while (window.pollEvent(windowEvent))
        {
            switch (windowEvent.type)
            {
                case sf::Event::Closed:
                    running = false;
                    break;
            }
        }

        // 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
        window.display();
    }

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

    glDeleteBuffers(1, &vbo);

    glDeleteVertexArrays(1, &vao);
    window.close();
}