C/SDL program, render not working with my renderer

Question

I'm was following this tutorial from Pikuma on how to setup a basic C/SDL2 gameloop, and it was all working really well. I was able to finish the tutorial and my program was running fine.

The problem apeared when I tried to split the code into multiple files(in the tutorial he was doing everything in the main function, besides some constants declaration)

I am still able to create the window and delete it, and I can still call my render function. BUT the render function doesn´t reconize my renderer. It was suposed to draw a simple red line in a gray background, but it is not working anymore ever since I split my functions into different files.

here it is how my files and code is arranged:

main.c

#include <stdio.h>
#include <SDL2/SDL.h>

#include "./constants.h"
#include "./init_and_destroy.h"
#include "./render.h"

//globals
int game_is_running = FALSE;
SDL_Window* my_window = NULL;
SDL_Renderer* my_renderer = NULL;

int last_frame_time = 0;

void setup() {

}

void process_input() {

    SDL_Event event;
    SDL_PollEvent(&event); //reference to event

    switch (event.type) {
        case SDL_QUIT:
            game_is_running = FALSE;
            break;
        case SDL_KEYDOWN:
            if(event.key.keysym.sym == SDLK_ESCAPE)
                game_is_running = FALSE;
            break;
    }
}

void update() {
    
    //---------------------------------FPS AND DELTA_TIME LOGIC---------------------------------------

    //caping frame rate
    int time_to_wait = FRAME_TARGET_TIME - (SDL_GetTicks() - last_frame_time);
    if (time_to_wait > 0 && time_to_wait <= FRAME_TARGET_TIME) {
        SDL_Delay(time_to_wait);
    }

    //delta time in seconds
    float delta_time = (SDL_GetTicks() - last_frame_time) / 1000.0f;

    last_frame_time = SDL_GetTicks();

    //------------------------------------------------------------------------------------------------

    //UPDATE LOGIC GOES HERE

}

int main() {
    
    game_is_running  = initialize_window(my_window, my_renderer);
    
    setup();

    while(game_is_running) {
        process_input();
        update();
        render(my_renderer);
    }

    destroy_window(my_window, my_renderer);

    return 0;
}

---

init_and_destroy.c

#include <stdio.h>
#include <SDL2/SDL.h>

#include "./constants.h"
#include "./init_and_destroy.h"


int initialize_window(SDL_Window* window, SDL_Renderer* renderer) {

    if (SDL_Init(SDL_INIT_EVERYTHING) != 0) {
        fprintf(stderr, "Error initializing SDL.\n");
        return FALSE;
    }

    window = SDL_CreateWindow(
        "My Window",
        SDL_WINDOWPOS_CENTERED, //x position
        SDL_WINDOWPOS_CENTERED, //y position
        WINDOW_WIDTH,
        WINDOW_HEIGHT,
        0
    );
    if(!window) {
        fprintf(stderr, "Error creating SDL Window.\n");
        return FALSE;
    }

    renderer = SDL_CreateRenderer(window, -1, 0);
    if(!renderer) {
        fprintf(stderr, "Error creating SDL Renderer.\n");
        return FALSE;
    }

    return TRUE;
}

void destroy_window(SDL_Window* window, SDL_Renderer* renderer) {
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDL_Quit();
}

---

render.c

#include <stdio.h>
#include <SDL2/SDL.h>

#include "./constants.h"
#include "./render.h"

void render(SDL_Renderer* renderer) {
       
    SDL_SetRenderDrawColor(renderer, 50, 50, 50, 255);
    SDL_RenderClear(renderer);
   
   //draw a red line
    SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
    for(int i = 0; i < WINDOW_WIDTH; i++) {
        SDL_RenderDrawPoint(renderer, i, i);
    }

    SDL_RenderPresent(renderer); //swap buffer

}

---

and my header files:

render.h

#ifndef RENDER
#define RENDER

void render(SDL_Renderer* renderer);

#endif

---

init_and_destroy.h

#ifndef INIT_AND_DESTROY
#define INIT_AND_DESTROY

int initialize_window(SDL_Window* window, SDL_Renderer* renderer);
void destroy_window(SDL_Window* window, SDL_Renderer* renderer);

#endif

---

print of my screen

I tried just declaring the render function without passing any parameters, and now I'm trying passing my SDL_Renderer as a parameter, and still nothing work, all I can see is a black window.

Answer 1

I see someone posted the answer already.

Just one quick tip: remember that we should loop the return of SDL_PollEvent.

void process_input() {
  SDL_Event event;
  while (SDL_PollEvent(&event)) {
    switch (event.type) {
      case SDL_QUIT:
        game_is_running = FALSE;
        break;
      case SDL_KEYDOWN:
        if (event.key.keysym.sym == SDLK_ESCAPE)
          game_is_running = FALSE;
        break;
    }
  }
}

We add this loop in one of the later lectures of the course.