Ok so I noticed that the program compiles fine in release mode, so I looked at what is done different in debug and release builds. In debug mode I log some information about the host system. The method
sf::Texture::getMaximumSize() seems to break the Shader code.
The following code does not work for me (ie. the Shader is not created, and there is OpenGL errors):
#include <SFML/System.hpp>
#include <SFML/Window.hpp>
#include <SFML/Graphics.hpp>
#include <iostream>
// Shader Bug Test
int main()
{
// comment the following line and everything works as expected
std::cout << "Maximale Texturgröße: " << sf::Texture::getMaximumSize() << std::endl;
// create the window
sf::RenderWindow window(sf::VideoMode(800, 600), "My window");
window.setFramerateLimit(60);
if(!sf::Shader::isAvailable()) {
std::cout << "Shader not available!" << std::endl;
}
sf::Shader m_FadeShader;
m_FadeShader.loadFromFile("FadeShader.frag", sf::Shader::Fragment);
m_FadeShader.setParameter("fRate", 0.5f);
sf::RectangleShape rect(sf::Vector2f(200, 200));
rect.setPosition(300, 200);
// run the program as long as the window is open
while (window.isOpen())
{
// check all the window's events that were triggered since the last iteration of the loop
sf::Event event;
while (window.pollEvent(event))
{
// "close requested" event: we close the window
if (event.type == sf::Event::Closed)
window.close();
// Escape key pressed, close window
if(event.type == sf::Event::KeyPressed && event.key.code == sf::Keyboard::Escape)
window.close();
}
// clear the window with black color
window.clear(sf::Color::Black);
// draw everything here...
window.draw(rect, &m_FadeShader);
// end the current frame
window.display();
}
return 0;
}
Shader code:
uniform float fRate;
void main()
{
vec4 color = vec4(1.0, 1.0, 1.0, 1.0);
color.a -= fRate;
gl_FragColor = color;
}
