Why do I keep getting a multiple definition error? - c

Question

Recently I've been working on my first game in C. (It is also my first programming language.) I finished a course ages ago and found a wonderful library called SDL2. It's great for graphics and all sorts. I've been also looking at other people's code and just been learning off of that too.
Anyway, my error is this "multiple definition of: function-name", I think it's a classic error as some people have experienced it too. It seems to have problem with all the functions in "pong_function.c". I’m also using the Code::Blocks IDE if anyone’s wondering.
In my pong.c file:
#include "pong.h"
int main( int argc, char** argv ) {
auto unsigned int col = 0x00;
paddle[0].x = 575 ;
paddle[0].y = 210 ;
paddle[0].hit = false ;
paddle[1].x = 0 ;
paddle[1].y = 205 ;
paddle[1].hit = false ;
ball.x = WIDTH / 2 ;
ball.y = HEIGHT / 2 ;
ball.speedX = 3;
ball.speedY = 0;
ball.direction = 2 ;
int n ;
init( ) ;
SDL_Window *window = SDL_CreateWindow( "Pong", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, WIDTH, HEIGHT, FLAG ) ;
SDL_Renderer *renderer = SDL_CreateRenderer( window, -1, SDL_RENDERER_ACCELERATED ) ;
load_files( renderer );
get_text( surface, renderer );
bool running = true;
while( running ) {
SDL_Event e;
while( SDL_PollEvent( &e ) ) {
switch( e.type ) {
case SDL_QUIT :
running = false;
break ;
switch( e.key.keysym.sym ) {
case SDL_KEYDOWN:
case SDLK_ESCAPE :
running = false ;
break;
}
default:
running = true;
}
}
input( );
update( );
draw_screen( renderer ) ;
}
surface = NULL; // Just in case
delete_items( window, renderer ) ;
return 0;
}
In my pong.h file:
#ifndef pong_h_
#define pong_h_
#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include <time.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
#include <SDL2/SDL_ttf.h>
typedef struct {
float x ;
float y ;
bool hit ;
} Paddle_t ;
typedef struct {
float x, speedX ;
float y , speedY ;
short direction ;
} Ball_t ;
const int WIDTH = 640 ;
const int HEIGHT = 480 ;
const int FLAG = 0 ;
extern unsigned int col ;
int tWidth = 0, tHeight = 0, tX = 0, tY = 0;
SDL_Texture *f_text = NULL ;
SDL_Texture *p_text = NULL ;
SDL_Texture *b_text = NULL ;
SDL_Surface *surface ;
TTF_Font *test;
Paddle_t paddle[ 2 ];
Ball_t ball;
extern void draw_screen( SDL_Renderer *renderer ) ;
extern void update( void ) ;
extern void load_files( SDL_Renderer *renderer ) ;
extern void input( void ) ;
extern void init( void ) ;
extern void get_text( SDL_Surface *surface, SDL_Renderer *renderer ) ;
extern void delete_items( SDL_Window *win, SDL_Renderer* renderer ) ;
#endif // pong_h_
Lastly, in my pong_func.c file:
#include "pong.h"
void draw_screen( SDL_Renderer *renderer ) {
// Clear screen to black colour
SDL_SetRenderDrawColor( renderer, col, col, col, col );
SDL_RenderClear( renderer ) ;
// Paddle (player 1)
SDL_Rect src = { 0, 0, 32*2, 32*2 } ;
SDL_Rect dRect = { paddle[ 0 ].x, paddle[ 0 ].y, 32*2, 32*2 } ;
SDL_RenderCopy( renderer, p_text, &src, &dRect ) ;
// Paddle (player 2)
SDL_Rect src2 = { 0, 0, 32*2, 32*2 } ;
SDL_Rect dRect2 = { paddle[ 1 ].x, paddle[ 1 ].y, 32*2, 32*2 } ;
SDL_RenderCopy( renderer, p_text, &src2, &dRect2 ) ;
// Ball
SDL_Rect bRect = { 0, 0, 32, 32 } ;
SDL_Rect bRect2 = { ball.x, ball.y, 32, 32 } ;
SDL_RenderCopy( renderer, b_text, &bRect, &bRect2 ) ;
// Font
SDL_Rect dstRect = { tX, tY, tWidth, tHeight } ;
SDL_RenderCopy( renderer, f_text, NULL, &dstRect ) ;
SDL_RenderPresent( renderer ) ;
}
void update( void ) {
// Nothing yet...
}
void load_files( SDL_Renderer *renderer ) {
if( ( surface = IMG_Load( "paddle.png" ) ) == NULL ) {
fprintf( stderr, "Unable to load file\n" ) ;
exit(-1);
}
p_text = SDL_CreateTextureFromSurface( renderer, surface ) ;
if( ( surface = IMG_Load( "ball.png" ) ) == NULL ) {
fprintf( stderr, "Unable to load file\n" ) ;
exit( -1 ) ;
}
b_text = SDL_CreateTextureFromSurface( renderer, surface ) ;
}
void input( void ) {
// Input
const Uint8 *state = SDL_GetKeyboardState( NULL ) ;
if( state[SDL_SCANCODE_A] ) paddle[ 0 ].y++;
if( state[SDL_SCANCODE_D] ) paddle[ 0 ].y--;
if( state[SDL_SCANCODE_LEFT] ) paddle[ 1 ].y++;
if( state[SDL_SCANCODE_RIGHT] ) paddle[ 1 ].y--;
}
void init( void ) {
// Init random
srand( time( NULL ) ) ;
// Init TTF
TTF_Init( ) ;
// Init PNG
IMG_Init( IMG_INIT_PNG ) ;
// Init SDL
if( SDL_Init(SDL_INIT_AUDIO) < 0 ) {
fprintf( stderr, "Unable to initialise SDL: %s", SDL_GetError() );
exit( -1 ) ;
}
}
void get_text( SDL_Surface *surface, SDL_Renderer *renderer ) {
const char *string = "Welcome to pong!" ;
SDL_Color clr = { 255, 255, 255 } ;
test = TTF_OpenFont( "slkscr.ttf", 25 ) ;
surface = TTF_RenderText_Solid(test, string, clr);
f_text = SDL_CreateTextureFromSurface(renderer, surface);
SDL_QueryTexture( f_text, NULL, NULL, &tWidth, &tHeight ) ;
}
void delete_items( SDL_Window *win, SDL_Renderer* renderer ) {
// Delete items
SDL_DestroyTexture( f_text ) ;
SDL_DestroyTexture( b_text ) ;
SDL_DestroyTexture( p_text ) ;
TTF_CloseFont( test ) ;
SDL_FreeSurface( surface ) ;
SDL_DestroyWindow( win ) ;
SDL_DestroyRenderer( renderer ) ;
SDL_Quit( );
IMG_Quit( );
TTF_Quit( );
}