i'm trying create tiled background in sdl, 1 scrolls , continues scroll indefinitely.
so, came code , tested out. works enough, can travel 1920 pixels along x axis , 1080 along y.
here's code:
void background::render(sdl_renderer *renderer){ int xoffset = 0; int yoffset = 0; for(int y = 0; (y * 411) < 1080; y++){ for(int x = 0; (x * 405) < 1920; x++){ xoffset = 0; yoffset = 0; if(gamemanager::getinstance().getglobalx() + (405 * x) + 405 < 0){ xoffset = 1920; } if(gamemanager::getinstance().getglobaly() + (411 * y) + 411 < 0){ yoffset = 1080; } sdl_rect backrect = {gamemanager::getinstance().getglobalx() + (405 * x) + xoffset, gamemanager::getinstance().getglobaly() + (411 * y) + yoffset, 405, 411}; sdl_rendercopy(renderer, resourcemanager::getinstance().gettexture("background"), 0, &backrect); } } } the getglobalx() , getglobaly() object should relative player.
you should able draw 1920x1080 background more once.
the algorithm this.
- draw background starting @ (-1920,0) (completely out of screen)
- draw copy of background, time starting @ (0,0).
- every frame, draw both backgrounds 1 pixel right, you'll have scrolling illusion, end of background exiting right come out left.
- once background @ step 1 has come (0,0), draw background @ (-1920,0) , keep scrolling.
so basically, push 2 backgrounds right , keep putting 1 on left every time need to. should simple code.
