Function main

examples/OpenGL.cpp:9–123

#include <cstdint>

int main() {
	// An sf::Window for raw OpenGL rendering.
	sf::Window app_window( sf::VideoMode( { 800, 600 } ), "SFGUI with OpenGL example", sf::Style::Titlebar | sf::Style::Close );

	// Create an SFGUI. This is required before doing anything with SFGUI.
	sfg::SFGUI sfgui;

	// Set the SFML Window's context back to the active one. SFGUI creates
	// a temporary context on creation that is set active.
	(void)app_window.setActive();

	// Initial OpenGL setup.
	// We have to set up our own OpenGL viewport because we are using an sf::Window.
	glViewport( 0, 0, static_cast<int>( app_window.getSize().x ), static_cast<int>( app_window.getSize().y ) );

	auto red_scale = sfg::Scale::Create( 0.f, 1.f, .01f, sfg::Scale::Orientation::HORIZONTAL );
	auto green_scale = sfg::Scale::Create( 0.f, 1.f, .01f, sfg::Scale::Orientation::HORIZONTAL );
	auto blue_scale = sfg::Scale::Create( 0.f, 1.f, .01f, sfg::Scale::Orientation::HORIZONTAL );
	auto angle_scale = sfg::Scale::Create( 0.f, 360.f, 1.f, sfg::Scale::Orientation::HORIZONTAL );
	auto auto_check = sfg::CheckButton::Create( "Auto" );

	auto table = sfg::Table::Create();
	table->SetRowSpacings( 5.f );
	table->SetColumnSpacings( 5.f );

	table->Attach( sfg::Label::Create( "Change the color of the rect using the scales below." ), sf::Rect<std::uint32_t>( { 0, 0 }, { 3, 1 } ), sfg::Table::FILL, sfg::Table::FILL );
	table->Attach( sfg::Label::Create( "Red:" ), sf::Rect<std::uint32_t>( { 0, 1 }, { 1, 1 } ), sfg::Table::FILL, sfg::Table::FILL );
	table->Attach( red_scale, sf::Rect<std::uint32_t>( { 1, 1 }, { 1, 1 } ), sfg::Table::FILL | sfg::Table::EXPAND, sfg::Table::FILL | sfg::Table::EXPAND );
	table->Attach( sfg::Label::Create( "Green:" ), sf::Rect<std::uint32_t>( { 0, 2 }, { 1, 1 } ), sfg::Table::FILL, sfg::Table::FILL );
	table->Attach( green_scale, sf::Rect<std::uint32_t>( { 1, 2 }, { 1, 1 } ), sfg::Table::FILL | sfg::Table::EXPAND, sfg::Table::FILL | sfg::Table::EXPAND );
	table->Attach( sfg::Label::Create( "Blue:" ), sf::Rect<std::uint32_t>( { 0, 3 }, { 1, 1 } ), sfg::Table::FILL, sfg::Table::FILL );
	table->Attach( blue_scale, sf::Rect<std::uint32_t>( { 1, 3 }, { 1, 1 } ), sfg::Table::FILL | sfg::Table::EXPAND, sfg::Table::FILL | sfg::Table::EXPAND );
	table->Attach( sfg::Label::Create( "Angle:" ), sf::Rect<std::uint32_t>( { 0, 4 }, { 1, 1 } ), sfg::Table::FILL, sfg::Table::FILL );
	table->Attach( angle_scale, sf::Rect<std::uint32_t>( { 1, 4 }, { 1, 1 } ), sfg::Table::FILL | sfg::Table::EXPAND, sfg::Table::FILL | sfg::Table::EXPAND );
	table->Attach( auto_check, sf::Rect<std::uint32_t>( { 2, 4 }, { 1, 1 } ), sfg::Table::FILL, sfg::Table::FILL );

	auto window = sfg::Window::Create();
	window->SetTitle( "SFGUI with OpenGL" );
	window->Add( table );

	sfg::Desktop desktop;
	desktop.Add( window );

	red_scale->SetValue( .2f );
	green_scale->SetValue( .5f );
	blue_scale->SetValue( .8f );

	glMatrixMode( GL_PROJECTION );
	glLoadIdentity();

	static const auto pi = 3.1415926535897932384626433832795f;
	static const auto fov = 90.f;
	static const auto near_distance = .1f;
	static const auto far_distance = 100.f;
	static const auto aspect = 800.f / 600.f;

	auto frustum_height = std::tan( fov / 360 * pi ) * near_distance;
	auto frustum_width = frustum_height * aspect;