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MORTAL2000/sfml-opemgl.cpp

Created January 14, 2019 13:33
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  1. MORTAL2000 created this gist Jan 14, 2019.
    115 changes: 115 additions & 0 deletions sfml-opemgl.cpp
    View file
    Original file line number Diff line number Diff line change
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    // Link statically with GLEW
    //#define GLEW_STATIC

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

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

    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();

    return 0;
    }