Bug QPainter crashes

SGaist

On a side note, modifying your pen and brush objects after setting them on painter won't modify what painter draws. You should first configure them and once that done set them on painter.

Sproza

thanks @SGaist! it should be obvious, a silly mistake on my part. Any ideas about the problem though??

SGaist

What's the size of your snake variable ? Are you sure the coordinates are valid ?

Sproza

Yes, coords are valid (250x and 250y whereas border is 500x500). Size of snake vector is 2.
Whole code is available at: https://github.com/Sproza/Snake.git
Just to make it clear because many find it confusing: Snake is a class with snake member vector and I named an instance of Snake "snake" in mainwindow constructor.

Sproza

Please? Anyone?

SGaist

Can you provide a more complete code sample ? We can only do guesses here since there are a lot of unknowns from your side.

mrjj

Hi
The code on git do not really compile out of the box.
Anyway, i saw this

for(int i = snake.size(); i >= 0; i--)

if snake.size() is 0 , wont that crash in snake[0].x ?
as you say >= ?

jsulm

@mrjj @Sproza Yes, it should be

for(int i = snake.size() - 1; i >= 0; i--)

Sproza

Yes, in that case it will crash, but snake.size() will never be 0 unless board -> STARTING_LENGTH will be 0. In Snake constructor program pushes additional dot to vector STARTING_LENGTH times.
But in reality there wont be way to change STARTING_LENGTH to 0 via menu.
So I do no think that's the reason. Just to be sure I tried snake.size() - 1 (although i have no idea why it would work) and it is not the solution.

mrjj

@Sproza

Ok, since you can run it then why not just find the crash with the debugger ?
When it crash the call stack will be shown and you can easy see where the crash happened.