Developing games in C++ using SDL

Using SDL to develop games in C

With the continuous development of the game industry and the expansion of the market, game development has gradually become a hot topic of concern. As a classic programming language, C also plays an important role in game development. This article will introduce how to use SDL to develop games in C, so that readers can initially understand the basic process and technical knowledge of game development.

SDL is a cross-platform multimedia library that provides a series of functions such as image processing, sound processing, and event processing, and can be used in game development. In order to use SDL, you need to download and install the SDL library files, including the SDL.h header file and SDL.lib library file.

Next we will illustrate the basic use of SDL through a simple game example. Suppose our game is a game where a ball moves in a window. First, we need to create the window and set the window size:

#include <SDL.h>

const int WIDTH = 640;
const int HEIGHT = 480;

int main(int argc, char* argv[])
{
  SDL_Init(SDL_INIT_VIDEO);
  SDL_Window* window = SDL_CreateWindow("Ball Game", 
    SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 
    WIDTH, HEIGHT, SDL_WINDOW_SHOWN);
  SDL_Renderer* renderer = SDL_CreateRenderer(window, -1, 
    SDL_RENDERER_ACCELERATED);
  ...
}

The above code uses SDL_Init to initialize SDL, uses SDL_CreateWindow to create the window, and uses SDL_CreateRenderer to create the renderer. The window needs a title (here it is "Ball Game"), the position of the window can be set to any position on the screen (here we set it to UNDEFINED and let the operating system determine its position), and the size of the window can also be set as needed. A renderer is a tool used to draw images into a window.

The main logic of the game is that the ball moves in the window, so we need to create a ball object and set its initial position and speed:

class Ball {
public:
  Ball(int x, int y, int w, int h): x(x), y(y), w(w), h(h), 
    vx(1), vy(1) {}
  void move() {
    x += vx;
    y += vy;
    if (x <= 0 || x >= WIDTH - w) vx = -vx;
    if (y <= 0 || y >= HEIGHT - h) vy = -vy;
  }
  void draw(SDL_Renderer* renderer) {
    SDL_Rect rect = { x, y, w, h };
    SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
    SDL_RenderFillRect(renderer, &rect);
  }
private:
  int x, y, w, h;
  int vx, vy;
};

int main(int argc, char* argv[])
{
  ...
  Ball ball(WIDTH / 2, HEIGHT / 2, 20, 20);
  ...
}

The above code defines a Ball class, using Used to describe the properties of the ball. At the beginning of the main function, we create a ball object ball and set its initial position and size.

Next, we need to update and draw the state of the ball in the game loop:

int main(int argc, char* argv[])
{
  ...
  while (true) {
    SDL_Event event;
    SDL_PollEvent(&event);
    if (event.type == SDL_QUIT) break;
    SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
    SDL_RenderClear(renderer);
    ball.move();
    ball.draw(renderer);
    SDL_RenderPresent(renderer);
    SDL_Delay(10);
  }
  ...
}

In the game loop, first handle the user's input event. If the user wants to close the window, exit the loop. Next, we use the SDL_RenderClear function to clear the window and use the move function in the Ball class to update the position of the ball. Subsequently, the ball is drawn into the window and displayed on the screen using the SDL_RenderPresent function.

The above is the basic process of using SDL to develop games in C. Of course, this is just a simple example. In fact, game development requires a deeper understanding and more complex technical applications. But through this example, we can initially understand the basic ideas and technical points of game development.

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