opengl_edited2.cpp

////////////////////////////////////////////////////////////
// Headers
////////////////////////////////////////////////////////////
#include <SFML/Graphics.hpp>
#include <SFML/OpenGL.hpp>

#include "ResourcePath.hpp"


////////////////////////////////////////////////////////////
/// Entry point of application
///
/// \return Application exit code
///
////////////////////////////////////////////////////////////
int main()
{
    // Request a 24-bits depth buffer when creating the window
    sf::ContextSettings contextSettings;
    contextSettings.depthBits = 24;

    // Create the main window
    sf::RenderWindow window(sf::VideoMode(800, 600), "SFML graphics with OpenGL", sf::Style::Default, contextSettings);
    window.setVerticalSyncEnabled(true);

    // Create a sprite for the background
    sf::Texture backgroundTexture;
    if (!backgroundTexture.loadFromFile(resourcePath() + "background.jpg"))
        return EXIT_FAILURE;
    sf::Sprite background(backgroundTexture);

    // Create some text to draw on top of our OpenGL object
    sf::Font font;
    if (!font.loadFromFile(resourcePath() + "sansation.ttf"))
        return EXIT_FAILURE;
    sf::Text text("SFML / OpenGL demo", font);
    text.setColor(sf::Color(255, 255, 255, 170));
    text.setPosition(250.f, 450.f);

    // Make the window the active target for OpenGL calls
    // Note: If using sf::Texture or sf::Shader with OpenGL,
    // be sure to call sf::Texture::getMaximumSize() and/or
    // sf::Shader::isAvailable() at least once before calling
    // setActive(), as those functions will cause a context switch
    window.setActive();

    // Define a 3D cube (6 faces made of 2 triangles composed by 3 vertices)
    static const GLfloat cube[] =
    {
        // positions    // texture coordinates
        -20, -20, -20,  0, 0,
        -20,  20, -20,  1, 0,
        -20, -20,  20,  0, 1,
        -20, -20,  20,  0, 1,
        -20,  20, -20,  1, 0,
        -20,  20,  20,  1, 1,

        20, -20, -20,  0, 0,
        20,  20, -20,  1, 0,
        20, -20,  20,  0, 1,
        20, -20,  20,  0, 1,
        20,  20, -20,  1, 0,
        20,  20,  20,  1, 1,

        -20, -20, -20,  0, 0,
        20, -20, -20,  1, 0,
        -20, -20,  20,  0, 1,
        -20, -20,  20,  0, 1,
        20, -20, -20,  1, 0,
        20, -20,  20,  1, 1,

        -20,  20, -20,  0, 0,
        20,  20, -20,  1, 0,
        -20,  20,  20,  0, 1,
        -20,  20,  20,  0, 1,
        20,  20, -20,  1, 0,
        20,  20,  20,  1, 1,

        -20, -20, -20,  0, 0,
        20, -20, -20,  1, 0,
        -20,  20, -20,  0, 1,
        -20,  20, -20,  0, 1,
        20, -20, -20,  1, 0,
        20,  20, -20,  1, 1,

        -20, -20,  20,  0, 0,
        20, -20,  20,  1, 0,
        -20,  20,  20,  0, 1,
        -20,  20,  20,  0, 1,
        20, -20,  20,  1, 0,
        20,  20,  20,  1, 1
    };

    // Create a clock for measuring the time elapsed
    sf::Clock clock;

    // Start game loop
    while (window.isOpen())
    {
        // Process events
        sf::Event event;
        while (window.pollEvent(event))
        {
            // Close window: exit
            if (event.type == sf::Event::Closed)
                window.close();

            // Escape key: exit
            if ((event.type == sf::Event::KeyPressed) && (event.key.code == sf::Keyboard::Escape))
                window.close();

            // Adjust the viewport when the window is resized
            if (event.type == sf::Event::Resized)
                glViewport(0, 0, event.size.width, event.size.height);
        }

        window.resetGLStates();
        // Load an OpenGL texture.
        // We could directly use a sf::Texture as an OpenGL texture (with its Bind() member function),
        // but here we want more control on it (generate mipmaps, ...) so we create a new one from an image
        GLuint texture = 0;
        {
            sf::Image image;
            if (!image.loadFromFile(resourcePath() + "texture.jpg"))
                return EXIT_FAILURE;
            glGenTextures(1, &texture);
            glBindTexture(GL_TEXTURE_2D, texture);
            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image.getSize().x, image.getSize().y, 0, GL_RGBA, GL_UNSIGNED_BYTE, image.getPixelsPtr());
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        }

        // Draw the background
        window.pushGLStates();
        window.draw(background);
        window.popGLStates();

        // Enable Z-buffer read and write
        glEnable(GL_DEPTH_TEST);
        glDepthMask(GL_TRUE);
        glClearDepth(1.f);

        // Disable lighting
        glDisable(GL_LIGHTING);

        // Configure the viewport (the same size as the window)
        glViewport(0, 0, window.getSize().x, window.getSize().y);

        // Setup a perspective projection
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        GLfloat ratio = static_cast<float>(window.getSize().x) / window.getSize().y;
        glFrustum(-ratio, ratio, -1.f, 1.f, 1.f, 500.f);

        // Bind the texture
        glEnable(GL_TEXTURE_2D);
        glBindTexture(GL_TEXTURE_2D, texture);

        // Enable position and texture coordinates vertex components
        glEnableClientState(GL_VERTEX_ARRAY);
        glEnableClientState(GL_TEXTURE_COORD_ARRAY);
        glVertexPointer(3, GL_FLOAT, 5 * sizeof(GLfloat), cube);
        glTexCoordPointer(2, GL_FLOAT, 5 * sizeof(GLfloat), cube + 3);

        // Disable normal and color vertex components
        glDisableClientState(GL_NORMAL_ARRAY);
        glDisableClientState(GL_COLOR_ARRAY);

        // Clear the depth buffer
        glClear(GL_DEPTH_BUFFER_BIT);

        // We get the position of the mouse cursor, so that we can move the box accordingly
        float x =  sf::Mouse::getPosition(window).x * 200.f / window.getSize().x - 100.f;
        float y = -sf::Mouse::getPosition(window).y * 200.f / window.getSize().y + 100.f;

        // Apply some transformations
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();
        glTranslatef(x, y, -100.f);
        glRotatef(clock.getElapsedTime().asSeconds() * 50.f, 1.f, 0.f, 0.f);
        glRotatef(clock.getElapsedTime().asSeconds() * 30.f, 0.f, 1.f, 0.f);
        glRotatef(clock.getElapsedTime().asSeconds() * 90.f, 0.f, 0.f, 1.f);

        // Draw the cube
        glDrawArrays(GL_TRIANGLES, 0, 36);

        // Draw some text on top of our OpenGL object
        window.pushGLStates();
        window.draw(text);
        window.popGLStates();

        // Finally, display the rendered frame on screen
        window.display();

        // Don't forget to destroy our texture
        glDeleteTextures(1, &texture);
    }
    
    return EXIT_SUCCESS;
}