cartrace/game.c

#include <stdio.h>
#include <math.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
#include <SDL2/SDL_timer.h>
#define PI 3.14159265

#define WINDOW_WIDTH 700
#define WINDOW_HEIGHT 500
#define FPS 60

#define SPEED 400 // pixels per second
#define STIRE_SPEED PI*2

SDL_Window* window;
SDL_Renderer* renderer;

SDL_Texture* Car_texture;
SDL_Rect Car_pos;

SDL_Surface* surface;
SDL_Texture* texture;

void quit(void){
  SDL_DestroyTexture(Car_texture);
  SDL_DestroyTexture(texture);
  SDL_DestroyRenderer(renderer);
  SDL_DestroyWindow(window);
  SDL_Quit();
}

// initialize SDL, create window and renderer
int init(void){
  // initialize SDL
  if (SDL_Init(SDL_INIT_VIDEO|SDL_INIT_TIMER) != 0){
      printf("error initializing SDL: %s\n", SDL_GetError());
      return 1;
  }

  // create window
  window = SDL_CreateWindow("Cart Race",
                            SDL_WINDOWPOS_CENTERED,
                            SDL_WINDOWPOS_CENTERED,
                            WINDOW_WIDTH, WINDOW_HEIGHT, 0);
  if(!window){
    printf("error create window: %s\n", SDL_GetError());
    SDL_Quit();
    return 2;
  }

  // create renderer
  renderer = SDL_CreateRenderer(
    window, -1,
    SDL_RENDERER_ACCELERATED|SDL_RENDERER_PRESENTVSYNC
  );

  if(!renderer){
    printf("error create renderer: %s\n", SDL_GetError());
    SDL_DestroyWindow(window);
    SDL_Quit();
    return 3;
  }
  return 0;
}

int createCar(){
  // create surface
  SDL_Surface* Car_surface = IMG_Load("img/car.png");
  if(!Car_surface){
    printf("error create surface: %s\n", SDL_GetError());
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDL_Quit();
    return 3;
  }

  // create texture
  Car_texture = SDL_CreateTextureFromSurface(renderer, Car_surface);
  SDL_FreeSurface(Car_surface);
  if(!Car_texture){
    printf("error create texture: %s\n", SDL_GetError());
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDL_Quit();
    return 3;
  }
  SDL_QueryTexture(Car_texture, NULL, NULL, &Car_pos.w, &Car_pos.h);
  return 0;
}

int main(void){
  if(init() != 0) return 1;
  if(createCar() != 0) return 2;

  Car_pos.x = (WINDOW_WIDTH - Car_pos.w) / 2;
  Car_pos.y = (WINDOW_HEIGHT- Car_pos.h) / 2;

  Uint8 close_requested = 0;
  int car_moving = 0;
  int direction = 0;

  double heading = PI;
  double speed = SPEED / FPS;
  double sspeed = STIRE_SPEED / FPS;

  double car_pos[2] = {Car_pos.x, Car_pos.y};

  while(!close_requested){
    // process events
    SDL_Event event;
    if(SDL_PollEvent(&event)){
      switch (event.type) {
        case SDL_QUIT:
          close_requested = 1;
          break;
        case SDL_KEYDOWN:
          switch (event.key.keysym.scancode) {
            case SDL_SCANCODE_UP:
            case SDL_SCANCODE_W:
              car_moving = 1;
              break;
            case SDL_SCANCODE_DOWN:
            case SDL_SCANCODE_S:
              car_moving = -1;
              break;
            case SDL_SCANCODE_LEFT:
            case SDL_SCANCODE_A:
              direction = 1;
              break;
            case SDL_SCANCODE_RIGHT:
            case SDL_SCANCODE_D:
              direction = -1;
            default:
              break;
          }
          break;
        case SDL_KEYUP:
          switch (event.key.keysym.scancode) {
            case SDL_SCANCODE_UP:
            case SDL_SCANCODE_W:
            case SDL_SCANCODE_DOWN:
            case SDL_SCANCODE_S:
              car_moving = 0;
              break;
            case SDL_SCANCODE_LEFT:
            case SDL_SCANCODE_A:
            case SDL_SCANCODE_RIGHT:
            case SDL_SCANCODE_D:
              direction = 0;
            default:
              break;
          }
        default:
          break;
      }
    }

    // clear the window
    SDL_RenderClear(renderer);

    // update position
    if(car_moving == 1){
      if(direction == 1){
        heading += sspeed;
      }else if(direction == -1){
        heading -= sspeed;
      }
      car_pos[0] += (sin(heading)*speed);
      car_pos[1] += (cos(heading)*speed);
    }else if(car_moving == -1){
      if(direction == 1){
        heading -= sspeed;
      }else if(direction == -1){
        heading += sspeed;
      }
      car_pos[0] -= (sin(heading)*speed);
      car_pos[1] -= (cos(heading)*speed);
    }

    if(car_pos[0] < 0){
      car_pos[0] = 0;
    }else if(car_pos[0]+Car_pos.w > WINDOW_WIDTH){
      car_pos[0] = WINDOW_WIDTH-Car_pos.w;
    }
    if(car_pos[1]< 0){
      car_pos[1]= 0;
    }else if(car_pos[1]+Car_pos.w > WINDOW_HEIGHT){
      car_pos[1]= WINDOW_HEIGHT-Car_pos.w;
    }

    Car_pos.x = (int) car_pos[0];
    Car_pos.y = (int) car_pos[1];

    printf("heading: %f\t%d\n", (heading), direction);
    printf("car posf: %f, %f\n", car_pos[0], car_pos[1]);
    printf("car pos: %u, %u\t%d\n", Car_pos.x, Car_pos.y, car_moving);

    // drow image
    SDL_RenderCopyEx(renderer, Car_texture, NULL, &Car_pos, 180-(heading*(180/PI)), NULL, SDL_FLIP_NONE);
    SDL_RenderPresent(renderer);

    // wait
    SDL_Delay(1000 / FPS);
  }

  // clean up resources before exiting
  SDL_DestroyTexture(texture);
  SDL_DestroyRenderer(renderer);
  SDL_DestroyWindow(window);
  SDL_Quit();
  return 0;
}