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////////////////////////////////////////////////////////////
// Headers
////////////////////////////////////////////////////////////
#include <SFML/Graphics.hpp>
#include <array>
#include <filesystem>
#include <iostream>
#include <cstdlib>
#define GLAD_GL_IMPLEMENTATION
#include <gl.h>
#ifdef SFML_SYSTEM_IOS
#include <SFML/Main.hpp>
#endif
#ifndef GL_SRGB8_ALPHA8
#define GL_SRGB8_ALPHA8 0x8C43
#endif
namespace
{
std::filesystem::path resourcesDir()
{
#ifdef SFML_SYSTEM_IOS
return "";
#else
return "resources";
#endif
}
} // namespace
////////////////////////////////////////////////////////////
/// Entry point of application
///
/// \return Application exit code
///
////////////////////////////////////////////////////////////
int main()
{
bool exit = false;
bool sRgb = false;
while (!exit)
{
// Request a 24-bits depth buffer when creating the window
sf::ContextSettings contextSettings;
contextSettings.depthBits = 24;
contextSettings.sRgbCapable = sRgb;
// Create the main window
sf::RenderWindow window(sf::VideoMode({800, 600}),
"SFML graphics with OpenGL",
sf::Style::Default,
sf::State::Windowed,
contextSettings);
window.setVerticalSyncEnabled(true);
window.setMinimumSize(sf::Vector2u(400, 300));
window.setMaximumSize(sf::Vector2u(1200, 900));
// Create a sprite for the background
const sf::Texture backgroundTexture(resourcesDir() / "background.jpg", sRgb);
const sf::Sprite background(backgroundTexture);
// Create some text to draw on top of our OpenGL object
const sf::Font font(resourcesDir() / "tuffy.ttf");
sf::Text text(font, "SFML / OpenGL demo");
sf::Text sRgbInstructions(font, "Press space to toggle sRGB conversion");
sf::Text mipmapInstructions(font, "Press return to toggle mipmapping");
text.setFillColor(sf::Color(255, 255, 255, 170));
sRgbInstructions.setFillColor(sf::Color(255, 255, 255, 170));
mipmapInstructions.setFillColor(sf::Color(255, 255, 255, 170));
text.setPosition({280.f, 450.f});
sRgbInstructions.setPosition({175.f, 500.f});
mipmapInstructions.setPosition({200.f, 550.f});
// Load a texture to apply to our 3D cube
sf::Texture texture(resourcesDir() / "logo.png");
// Attempt to generate a mipmap for our cube texture
// We don't check the return value here since
// mipmapping is purely optional in this example
(void)texture.generateMipmap();
// Make the window the active window for OpenGL calls
if (!window.setActive(true))
{
std::cerr << "Failed to set window to active" << std::endl;
return EXIT_FAILURE;
}
// Load OpenGL or OpenGL ES entry points using glad
#ifdef SFML_OPENGL_ES
gladLoadGLES1(sf::Context::getFunction);
#else
gladLoadGL(sf::Context::getFunction);
#endif
// Enable Z-buffer read and write
glEnable(GL_DEPTH_TEST);
glDepthMask(GL_TRUE);
#ifdef SFML_OPENGL_ES
glClearDepthf(1.f);
#else
glClearDepth(1.f);
#endif
// Disable lighting
glDisable(GL_LIGHTING);
// Configure the viewport (the same size as the window)
glViewport(0, 0, static_cast<GLsizei>(window.getSize().x), static_cast<GLsizei>(window.getSize().y));
// Setup a perspective projection
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
const GLfloat ratio = static_cast<float>(window.getSize().x) / static_cast<float>(window.getSize().y);
#ifdef SFML_OPENGL_ES
glFrustumf(-ratio, ratio, -1.f, 1.f, 1.f, 500.f);
#else
glFrustum(-ratio, ratio, -1.f, 1.f, 1.f, 500.f);
#endif
// Bind the texture
glEnable(GL_TEXTURE_2D);
sf::Texture::bind(&texture);
// Define a 3D cube (6 faces made of 2 triangles composed by 3 vertices)
// clang-format off
constexpr std::array<GLfloat, 180> 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
};
// clang-format on
// Enable position and texture coordinates vertex components
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glVertexPointer(3, GL_FLOAT, 5 * sizeof(GLfloat), cube.data());
glTexCoordPointer(2, GL_FLOAT, 5 * sizeof(GLfloat), cube.data() + 3);
// Disable normal and color vertex components
glDisableClientState(GL_NORMAL_ARRAY);
glDisableClientState(GL_COLOR_ARRAY);
// Make the window no longer the active window for OpenGL calls
if (!window.setActive(false))
{
std::cerr << "Failed to set window to inactive" << std::endl;
return EXIT_FAILURE;
}
// Create a clock for measuring the time elapsed
const sf::Clock clock;
// Flag to track whether mipmapping is currently enabled
bool mipmapEnabled = true;
// Start game loop
while (window.isOpen())
{
// Process events
while (const std::optional event = window.pollEvent())
{
// Window closed or escape key pressed: exit
if (event->is<sf::Event::Closed>() ||
(event->is<sf::Event::KeyPressed>() &&
event->getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Escape))
{
exit = true;
window.close();
}
// Return key: toggle mipmapping
if (const auto* keyPressed = event->getIf<sf::Event::KeyPressed>();
keyPressed && keyPressed->code == sf::Keyboard::Key::Enter)
{
if (mipmapEnabled)
{
// We simply reload the texture to disable mipmapping
texture = sf::Texture(resourcesDir() / "logo.png");
// Rebind the texture
sf::Texture::bind(&texture);
mipmapEnabled = false;
}
else if (texture.generateMipmap())
{
mipmapEnabled = true;
}
}
// Space key: toggle sRGB conversion
if (const auto* keyPressed = event->getIf<sf::Event::KeyPressed>();
keyPressed && keyPressed->code == sf::Keyboard::Key::Space)
{
sRgb = !sRgb;
window.close();
}
// Adjust the viewport when the window is resized
if (const auto* resized = event->getIf<sf::Event::Resized>())
{
const sf::Vector2u textureSize = backgroundTexture.getSize();
// Make the window the active window for OpenGL calls
if (!window.setActive(true))
{
std::cerr << "Failed to set window to active" << std::endl;
return EXIT_FAILURE;
}
const auto [width, height] = resized->size;
glViewport(0, 0, static_cast<GLsizei>(width), static_cast<GLsizei>(height));
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
const GLfloat newRatio = static_cast<float>(width) / static_cast<float>(height);
#ifdef SFML_OPENGL_ES
glFrustumf(-newRatio, newRatio, -1.f, 1.f, 1.f, 500.f);
#else
glFrustum(-newRatio, newRatio, -1.f, 1.f, 1.f, 500.f);
#endif
// Make the window no longer the active window for OpenGL calls
if (!window.setActive(false))
{
std::cerr << "Failed to set window to inactive" << std::endl;
return EXIT_FAILURE;
}
sf::View view;
view.setSize(sf::Vector2f(textureSize));
view.setCenter(sf::Vector2f(textureSize) / 2.f);
window.setView(view);
}
}
// Draw the background
window.pushGLStates();
window.draw(background);
window.popGLStates();
// Make the window the active window for OpenGL calls
if (!window.setActive(true))
{
// On failure, try re-creating the window, as it is intentionally
// closed when changing color space.
continue;
}
// Clear the depth buffer
glClear(GL_DEPTH_BUFFER_BIT);
// We get the position of the mouse cursor (or touch), so that we can move the box accordingly
sf::Vector2i pos;
#ifdef SFML_SYSTEM_IOS
pos = sf::Touch::getPosition(0);
#else
pos = sf::Mouse::getPosition(window);
#endif
const float x = static_cast<float>(pos.x) * 200.f / static_cast<float>(window.getSize().x) - 100.f;
const float y = -static_cast<float>(pos.y) * 200.f / static_cast<float>(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);
// Make the window no longer the active window for OpenGL calls
if (!window.setActive(false))
{
std::cerr << "Failed to set window to inactive" << std::endl;
return EXIT_FAILURE;
}
// Draw some text on top of our OpenGL object
window.pushGLStates();
window.draw(text);
window.draw(sRgbInstructions);
window.draw(mipmapInstructions);
window.popGLStates();
// Finally, display the rendered frame on screen
window.display();
}
}
return EXIT_SUCCESS;
}
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