Sfml: Android sf::Text bug

[FQLT]

Subject of the issue

When drawing sf::Text on android getting: "sfml-error: Could not copy vertex buffer"

Your environment

Confirmed on Android 5.1, 8.0, 9.0
SFML version: 2.5.1
Compiler: clang
NDK version: 20
Compiler flags: -g -O0 -fexceptions -std=c++17

Steps to reproduce

#include <SFML/System.hpp>
#include <SFML/Window.hpp>
#include <SFML/Graphics.hpp>
#include <SFML/Audio.hpp>
#include <SFML/Network.hpp>
#include <vector>

int main(int argc, char *argv[])
{
    sf::VideoMode screen(sf::VideoMode::getDesktopMode());
    sf::RenderWindow window(screen, "");
    sf::Font font;
    if (!font.loadFromFile("sansation.ttf"))
        return EXIT_FAILURE;
    sf::View view = window.getDefaultView();
    std::vector<sf::Text> displayed;
    bool active = true;
    while (window.isOpen())
    {
        sf::Event event;

        while (active ? window.pollEvent(event) : window.waitEvent(event))
        {
            switch (event.type)
            {
                case sf::Event::Closed:
                    window.close();
                    break;
                case sf::Event::KeyPressed:
                    if (event.key.code == sf::Keyboard::Escape)
                        window.close();
                    break;
                case sf::Event::MouseLeft:
                    active = false;
                    break;
                case sf::Event::MouseEntered:
                    active = true;
                    break;
                case sf::Event::TouchBegan:
                    displayed.emplace_back("font",font, 40);
                    displayed.back().setPosition(0,displayed.size()*40);
                    break;
            }
        }

        if (active)
        {
            window.clear();
            for(auto &elem : displayed)
                window.draw(elem);
            window.display();
        }
        else {
            sf::sleep(sf::milliseconds(100));
        }
    }
}

Expected behavior

Correct drawing sf::Text without error.

Actual behavior

When adding sf::Text to vector and drawing it, getting bugs with correct draw and SFML error. To reproduce this, tap on screen 4-6 times.

[binary1248]

Even though this seems rather strange, we might be hitting some ridiculously low implementation limit on the number of supported VBOs. Regardless of the actual reason, #1584 should alleviate this issue.

[dmitry-t]

@binary1248 I'd like to notice that we talk about 4-6 text instances 4 glyphs each. The limit cannot be _so_ low. I use SFML in my project and had no issues with several dozens of text instances even on Android.

[binary1248]

Besides the number of VBOs that are created, I don't see any difference in program state between 2 taps and 4 taps, hence my assumption.

@FQLT can you run this in debug configuration with some kind of console open in the background? Any OpenGL errors that occur will be logged to the console this way.

[FQLT]

@binary1248 Here https://pastebin.com/BAEvMMBK is full console output from android studio. SFML vertex buffer errors starts producing after several taps. I found solution for me, in std::vector I store std::string instead of sf::Text, and on draw I create instances of sf::Text from std::string and draw it.

[MarioLiebisch]

Does this also happen if you sleep for 2 seconds after window creation? And does it happen if you add new text instances based on time rather than taps?

[FQLT]

Does this also happen if you sleep for 2 seconds after window creation? And does it happen if you add new text instances based on time rather than taps?

Yes and yes

[dmitry-t]

Besides the number of VBOs that are created, I don't see any difference in program state between 2 taps and 4 taps, hence my assumption.

I might imagine that there is a vector object (sf::Text) copying issue when the displayed vector reallocates its storage.

[tejohnso]

I'm seeing this "sfml-error: Could not copy vertex buffer" message whenever there is a Sprite in a constructor or I try to emplace a sprite into a vector.

Looks like it's successfully creating the vertex buffer "for copying" here, but then failing to make the copy here because of this.

[esbvaGames]

Android - 22