Printing a 2d array in sfml from a text file - c++

Question

Im trying to print out a 2d array of characters that is from a text file, into a renderwindow using the window.draw() function. However, everything seems to work perfectly fine, except that when printing its skipping exactly one character.
For instance if i had a line of 15 chars, it will only print 8,but when i print it on the terminal it prints it perfectly fine, I simply dont know why its behaving like that, tried several things like changing the text file itself, or changing the size. Nothing seems to work for me. any ideas or help is very much appreciated.
here is the part of the code:
void Level::printgrid(int level)
{
sf::RenderWindow window(sf::VideoMode(800, 600), "Game On");
sf::Font MyFont;
if (!MyFont.loadFromFile("tnr.ttf"))
{
// Error...
}
ifstream my_file("nn.txt"); //text that i will be reading from
char number;
int i = 0; //to help loop
int j = 0;
while (window.isOpen())
{
sf::Event event;
while (window.pollEvent(event))
{
if (event.type == sf::Event::Closed)
window.close();
else
{
window.clear();
while (i<row) // ive tried 2 for loops that didnt work cause
{ // it kept re-entering those loops
while (j<col)
{
my_file.get(grid[i][j]); //getting the chars one by one
cout << grid[i][j]; // printing them on terminal
//so i can check its correct
//changing to text that is drawable to print in window
sf::Text text(grid[i][j], MyFont, 30);
text.setPosition(0 + (30 * i), 0 + (30 * j));
// drawing it in window
window.draw(text);
window.display();
j++;
}
my_file.get(number);
cout << endl;
i++;
j = 0;
}
}
}
}
}

Answer 1

There are a few issues with your code, but the most apparent problem is the fact that you're always drawing only one character, then presenting the result (which will flip buffers).
Due to this you're basically alternating characters between the two buffers (since SFML is double buffering).
In addition, you're continually reading from your file, recreating the characters/text elements, etc. which is not very effective and should fail once you reach the end of the file.
For some actual game or program, you should work on optimizing the drawing (drawing 10 characters at once as one sf::Text is faster than drawing 10 individual sf::Text objects). I'll be ignoring this for simplicity for now.
The following is just a quick (untested) example to show you the basic idea.
// First I'd use some container to store our `sf::Text` objects
// This will just create all the objects
std::vector<sf::Text> chars(rows * cols);
// Now let's read the characters and add to our vector
for (std::size_t y = 0; y < rows; ++y) {
for (std::size_t x = 0; x < cols; ++x) {
// Just an alias to simplify the following lines
sf::Text &text = chars[y * cols + x];
// Now just set up everything
text.setFont(my_font);
text.setFillColor(sf::Color::White);
text.setCharacterSize(30);
text.setPosition(30 * x, 30 * y);
text.setString(my_file.get());
}
}
while (window.isOpen()) {
sf::Event event;
while (window.pollEvent(event)) {
// Just your usual event handling
}
window.clear();
// Iterate over all elements and draw them
for (const auto &text : chars)
window.draw(text);
window.display();
}
If you're trying to create some kind of graphical console, you should put all characters into some sf::VertexArray or potentially render them using a shader.