SDL, How can I make the background picture render? - c++

Question

I had a render problem, but I fixed that. The problem is, is that the picture won't actually show up. I know the picture gets loaded because I have an error handler if it isn't loaded. I know the code is messy, but I just need the picture to show up.
#include <SDL/SDL.h>
#include <stdio.h>
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
const int fps = 60;
SDL_Window *window;
int main(int argc, char **argv)
{
SDL_Init(SDL_INIT_EVERYTHING);
window = SDL_CreateWindow("", 300, 100, 1024, 800, SDL_WINDOW_OPENGL);
if (window == NULL)
{
cout << ("could not create window: %s/n", SDL_GetError());
return 1;
}
SDL_Renderer *renderer = SDL_CreateRenderer(window, -1, 0);
int x = 0, y = 0;
SDL_Surface *screen;
SDL_Surface *background = SDL_LoadBMP("hockeyrink.bmp");
if(background == NULL)
{
SDL_ShowSimpleMessageBox(0, "Background init error", SDL_GetError(), window);
}
if(renderer == NULL)
{
SDL_ShowSimpleMessageBox(0, "Renderer init error", SDL_GetError(), window);
}
SDL_Texture *texture = SDL_CreateTextureFromSurface(renderer,background);
if(texture == NULL)
{
SDL_ShowSimpleMessageBox(0, "Texture init error", SDL_GetError(), window);
}
const int speed = 5;
SDL_Rect camera;
camera.x = 0; //Don't worry about this camera, I need this after i get the background working.
camera.y = 0;
camera.w = 800;
camera.h = 600;
bool b[2] = {0,0};
Uint32 start;
bool running = true;
while (running)
{
start = SDL_GetTicks();
SDL_Event event;
while(SDL_PollEvent(&event))
{
switch(event.type)
{
case SDL_QUIT:
running = false;
SDL_DestroyTexture(texture);
SDL_FreeSurface(background);
SDL_DestroyRenderer(renderer);
SDL_DestroyWindow(window);
SDL_Quit();
break;
case SDL_KEYDOWN:
switch(event.key.keysym.sym)
{
case SDLK_UP:
b[0]=1;
break;
case SDLK_LEFT:
b[1]=1;
break;
}
break;
case SDL_KEYUP:
switch(event.key.keysym.sym)
{
case SDLK_UP:
b[0]=0;
break;
case SDLK_LEFT:
b[1]=0;
break;
}
break;
}
}
if(b[0])
{
x+=speed;
camera.y+=speed;
if (camera.y > 3000-800)
{
camera.y=0;
}
}
else if(b[1])
{
x-=speed;
camera.y-=speed;
if (camera.y <= 0)
{
camera.y = 2000-800;
}
SDL_RenderCopy(renderer, texture, NULL, NULL);
SDL_RenderPresent(renderer);
}
if(1000/fps>SDL_GetTicks()-start)
{
SDL_Delay(1000/fps-(SDL_GetTicks() - start));
}
}
return 0;
}

Answer 1

You have initialized b[1] to 0 and the texture is rendered only when b[1] is 1 as in your code.
You should either put the lines:
SDL_RenderCopy(renderer, texture, NULL, NULL);
SDL_RenderPresent(renderer);
before the loop,
or press the left key of your keyboard(i.e. SDLK_LEFT)
to render and present the image on the screen.
It works in my system, so it should work in yours, too.