main.c

#include <stdio.h>
#include <stdbool.h>
#include <SDL2/SDL.h>
#include "const.h"
//****** GLOBAL VARS ******\\

int game_is_running = false;
SDL_Window* window = NULL;
SDL_Renderer* renderer = NULL;
int last_frame_time = 0;


struct game_object {
    float x;
    float y;
    float width;
    float height;
    float vel_x;
    float vel_y;
} ball, paddle;


//**** INITIALIZE SDL WINDOW *****\\

int initialize_window(void) {
    if (SDL_Init(SDL_INIT_EVERYTHING) != 0) {
        fprintf(stderr, "Error initializing SDL.\n");
        return false;
    }
    window = SDL_CreateWindow(
        NULL,
        SDL_WINDOWPOS_CENTERED,
        SDL_WINDOWPOS_CENTERED,
        WINDOW_WIDTH,
        WINDOW_HEIGHT,
        SDL_WINDOW_BORDERLESS
    );
    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;
}


//***** POLL SDL EVENTS AND PROCESS KEYBOARD INPUT ******\\

void process_input(void) {
    SDL_Event event;
    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;
            }
            if(event.key.keysym.sym==SDLK_LEFT){

            paddle.vel_x=-300;
            }
            if(event.key.keysym.sym==SDLK_RIGHT){

            paddle.vel_x=300;
            }
            break;
        case SDL_KEYUP:
            paddle.vel_x=0;
            break;
    }
}

//***** SETUP FUNCTION *****\\

void setup(void) {
    // Initialize the ball object moving down at a constant velocity
    ball.width = 15;
    ball.height = 15;
    ball.x = 20;
    ball.y = 20;
    ball.vel_x = 300;
    ball.vel_y = 300;
    // Initialize the paddle position at the bottom of the screen
    paddle.width = 100;
    paddle.height = 20;
    paddle.x = (WINDOW_WIDTH / 2) - (paddle.width / 2);
    paddle.y = WINDOW_HEIGHT - 40;
    paddle.vel_x = 0;
    paddle.vel_y = 0;
}

//***** UPDATE FUNCTION *****\\

void update(void) {

    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);

    float delta_time = (SDL_GetTicks() - last_frame_time) / 1000.0;


    last_frame_time = SDL_GetTicks();

    ball.x += ball.vel_x * delta_time;
    ball.y += ball.vel_y * delta_time;

    paddle.x += paddle.vel_x * delta_time;

    if(ball.x<0 || ball.x>WINDOW_WIDTH-ball.width)
        ball.vel_x =-ball.vel_x;
    if(ball.y<0 || ball.y>WINDOW_HEIGHT-ball.height)
        ball.vel_y =-ball.vel_y;
    if (ball.y + ball.height >= paddle.y && ball.x + ball.width >= paddle.x && ball.x <= paddle.x + paddle.width)
        ball.vel_y = -ball.vel_y;
    if(paddle.x<0)
    paddle.x=0;
    if(paddle.x>WINDOW_WIDTH-paddle.width)
    paddle.x=WINDOW_WIDTH-paddle.width;

if (ball.y + ball.height > WINDOW_HEIGHT) {
        ball.x = WINDOW_WIDTH / 2;
        ball.y = 0;}
}

//***** RENDER FUNCTION *****\\

void render(void) {
    SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
    SDL_RenderClear(renderer);

    // Draw a rectangle for the ball object
    SDL_Rect ball_rect = {
        (int)ball.x,
        (int)ball.y,
        (int)ball.width,
        (int)ball.height
    };
    SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
    SDL_RenderFillRect(renderer, &ball_rect);

    // Draw a rectangle for the paddle object
    SDL_Rect paddle_rect = {
        (int)paddle.x,
        (int)paddle.y,
        (int)paddle.width,
        (int)paddle.height
    };
    SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
    SDL_RenderFillRect(renderer, &paddle_rect);

    SDL_RenderPresent(renderer);
}


//***** DESTROY SDL + WINDOW *****\\

void destroy_window(void) {
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDL_Quit();
}


// Main function
int main(int argc, char* args[]) {
    game_is_running = initialize_window();

    setup();

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

    destroy_window();

    return 0;
}