sdl - SDL2 C++ - Multiple Image Rendering Bug -

before begin, ide use code::blocks.

i going practice things learned online sdl in project separate study project. wanted load image of ball on top of background. worked fine in study project. replicated code on test project, , ball disappeared. background visible.

i removed codes involve background , worked fine.

my code:

#include <iostream> #include <cstdlib> #include <sdl.h> #include <sdl_image.h> #undef main  using namespace std;  sdl_texture *loadtexture (string filepath, sdl_renderer *rendertarget){     sdl_texture *texture = 0;     sdl_surface *surface = img_load(filepath.c_str());      texture = sdl_createtexturefromsurface(rendertarget, surface);      sdl_freesurface(surface);      return texture; }  int main () {      sdl_window *window = 0;     sdl_texture *ball = 0;     sdl_texture *background_sky = 0;      sdl_renderer *rendertarget = 0;      int framew, frameh;     int texturew, textureh;      //--crop instructions--//     framew = texturew / 1; //row division     frameh = textureh / 1; //column division      sdl_rect ballcrop;     ballcrop.x = ballcrop.y = 0;     ballcrop.w = framew; //length of selected area     ballcrop.h = frameh; //height of selected area      sdl_rect ballpos;     ballpos.x = ballpos.y = 10; //ball position     ballpos.w = ballpos.h = 64; //size of crop     //---------------------//      sdl_init(sdl_init_everything);     img_init(img_init_png);      window = sdl_createwindow("ball", sdl_windowpos_centered, sdl_windowpos_centered, 500, 500, sdl_window_shown);     rendertarget = sdl_createrenderer(window, -1, sdl_renderer_accelerated | sdl_renderer_presentvsync);      ball = loadtexture("ball.png", rendertarget);     background_sky = loadtexture("bg_sky.png", rendertarget);       sdl_querytexture(ball, null, null, &texturew, &textureh); //crop action      bool active = true;     sdl_event ev;      while (active) {         while (sdl_pollevent(&ev)!=0) {             if (ev.type == sdl_quit)                 active = false;              else if (ev.type == sdl_keydown) {                 switch (ev.key.keysym.sym) {                 case sdlk_up:                     ballpos.y -= 5;                     break;                 case sdlk_down:                     ballpos.y += 5;                     break;                 }             }         }         sdl_renderclear(rendertarget);          sdl_rendercopy(rendertarget, background_sky, null, null);         sdl_rendercopy(rendertarget, ball, &ballcrop, &ballpos);          sdl_renderpresent(rendertarget);     }      sdl_destroywindow(window);     sdl_destroytexture(background_sky);     sdl_destroytexture(ball);      sdl_destroyrenderer(rendertarget);      window = 0;     ball = background_sky = 0;     rendertarget = 0;      img_quit();     sdl_quit();      return 0; } 

i dont think want show source code of study project because extremely messy.

any appreciated :)

you have error in calculation of framew , frameh; code calculates

//--crop instructions--// framew = texturew / 1; //row division frameh = textureh / 1; //column division 

uses texturew , textureh before these initialised. move entire 'crop instructions' block until after have called sdl_querytexture.