C++ & SDL2 - Big Graphics Bug - Any ideas welcome

Nick · 2022-04-06T17:38:37

Ahh…my enemy sprite draw routine is bugged and I can't find the problem. For the time being the routine reads a 20y, by 76x, int array, and creates a new instance of vector, Class Enemy, enemies for each ‘1’, using the arrays index as a proxy for the map location (1080y, by 7860x). The draw routine then cycles through each instance of vector, Class Enemy, enemies, loads the image template, sets the x & y relative to the 7680x1080, checks to see if each instance is currently in bounds (within the viewing window, and places the 50x50 enemy (cherry) sprite on renderer. I've got std::cout's at each stage showing me the correct number of enemies, in the correct x/y relative to the map, and then in the correct x/y relative to the viewing window - ..but I'm getting bizarre results. It only ever prints the sprites in the right location, but it never prints all the sprites. Yet, it is very consistent in the sprites it omits. Doesn't feel like an memory issue? but I just don't know what to think at this stage. [Edit -1/04/2022 - I've removed the source code and replaced it with the link below to the the games GitHub page - including source code, installer and executables] https://nickchantrell.github.io/Parrallax-Zoom-SDL2/ Thank you for the suggestion @fleabay

For Beginners Hobby game C++ SDL2 Debug

Started by Nick72c March 31, 2022 09:01 AM

21 comments, last by Nick72c 2 years, 8 months ago

fleabay

1,327

April 06, 2022 05:27 PM

I'm lazy and just allocate as many objects as I ever plan on having so the container never gets moved.

.hpp

std::vector<GameObject *> m_objects;

.cpp

m_objects.reserve(256);

🙂🙂🙂🙂🙂<←The tone posse, ready for action.

Nick72c

Author

April 06, 2022 05:38 PM

@joej @fleabay

Thank you both - this has been bugging me (excuse the pun) for days.

Hearing Joe's explanation I was just about to ripe out the vectors and replace them with fixed size arrays, but enemy_image.reserve(20); worked a treat ? thank you!

https://nickchantrell.github.io/Parrallax-Zoom-SDL2/

https://www.deftdelta.com

Download Parallax Zoom!! (pre-alpha) - https://www.gamedev.net/projects/4262-parallax-zoom/