C / C++中的SDL库和示例

SDL是Simple DirectMedia Layer ，它是一个跨平台开发库，旨在通过OpenGL和Direct3D提供对音频，键盘，鼠标，操纵杆和图形硬件的低级访问，可用于制作动画和视频游戏。

• 它基本上提供了一组API，可与各种设备(例如图形硬件，音频，键盘，鼠标等)进行交互。
• 它是用C编程语言编写的，并且可以与C++和其他各种语言(如c＃和Python。

在Linux上安装(对于使用apt软件包管理器的操作系统，例如：Ubuntu)：

1. 在终端上运行命令sudo apt-get update 。
2. 在终端上运行命令sudo apt-get install clang 。
3. 在终端上运行命令sudo apt-get install libsdl2-2.0-0 libsdl2-dbg libsdl2-dev libsdl2-image-2.0-0 libsdl2-image-dbg libsdl2-image-dev 。
4. 我们需要创建一个Makefile，因此请打开您选择的文本编辑器并开始编写以下代码。

# A simple Makefile for compiling small SDL projects

# set the compiler
CC := clang

# set the compiler flags
CFLAGS := `sdl2-config --libs --cflags` -ggdb3 -O0 --std=c99 -Wall -lSDL2_image -lm
# add header files here
HDRS :=

# add source files here
SRCS := #file-name.c

# generate names of object files
OBJS := $(SRCS:.c=.o)

# name of executable
EXEC := #name your executable file

# default recipe
all: $(EXEC)
 
showfont: showfont.c Makefile
    $(CC) -o $@ $@.c $(CFLAGS) $(LIBS)

glfont: glfont.c Makefile
    $(CC) -o $@ $@.c $(CFLAGS) $(LIBS)

# recipe for building the final executable
$(EXEC): $(OBJS) $(HDRS) Makefile
    $(CC) -o $@ $(OBJS) $(CFLAGS)

# recipe for building object files
#$(OBJS): $(@:.o=.c) $(HDRS) Makefile
#    $(CC) -o $@ $(@:.o=.c) -c $(CFLAGS)

# recipe to clean the workspace
clean:
    rm -f $(EXEC) $(OBJS)

.PHONY: all clean

头文件：

CPP

// for initializing and sutdown functions
#include 
 
// for rendering images and graphics on screen
#include 
 
// for using SDL_Delay() functions
#include 

初始化：

CPP

#include 
#include 
#include 
 
int main(int argc, char *argv[])
{
 
    // retutns zero on success else non-zero
    if (SDL_Init(SDL_INIT_EVERYTHING) != 0) {
        printf("error initializing SDL: %s\n", SDL_GetError());
    }
    SDL_Window* win = SDL_CreateWindow("GAME",
                                       SDL_WINDOWPOS_CENTERED,
                                       SDL_WINDOWPOS_CENTERED,
                                       1000, 1000, 0);
    while (1)
        ;
 
    return 0;
}

这将在屏幕上创建一个空窗口。
输出：

我们将编写一个简单的程序来解释渲染和I / O处理：

CPP

#include 
#include 
#include 
 
int main(int argc, char *argv[])
{
 
    // retutns zero on success else non-zero
    if (SDL_Init(SDL_INIT_EVERYTHING) != 0) {
        printf("error initializing SDL: %s\n", SDL_GetError());
    }
    SDL_Window* win = SDL_CreateWindow("GAME", // creates a window
                                       SDL_WINDOWPOS_CENTERED,
                                       SDL_WINDOWPOS_CENTERED,
                                       1000, 1000, 0);
 
    // triggers the program that controls
    // your graphics hardware and sets flags
    Uint32 render_flags = SDL_RENDERER_ACCELERATED;
 
    // creates a renderer to render our images
    SDL_Renderer* rend = SDL_CreateRenderer(win, -1, render_flags);
 
    // creates a surface to load an image into the main memory
    SDL_Surface* surface;
 
    // please provide a path for your image
    surface = IMG_Load("path");
 
    // loads image to our graphics hardware memory.
    SDL_Texture* tex = SDL_CreateTextureFromSurface(rend, surface);
 
    // clears main-memory
    SDL_FreeSurface(surface);
 
    // let us control our image position
    // so that we can move it with our keyboard.
    SDL_Rect dest;
 
    // connects our texture with dest to control position
    SDL_QueryTexture(tex, NULL, NULL, &dest.w, &dest.h);
 
    // adjust height and width of our image box.
    dest.w /= 6;
    dest.h /= 6;
 
    // sets initial x-position of object
    dest.x = (1000 - dest.w) / 2;
 
    // sets initial y-position of object
    dest.y = (1000 - dest.h) / 2;
 
    // controls annimation loop
    int close = 0;
 
    // speed of box
    int speed = 300;
 
    // annimation loop
    while (!close) {
        SDL_Event event;
 
        // Events mangement
        while (SDL_PollEvent(&event)) {
            switch (event.type) {
 
            case SDL_QUIT:
                // handling of close button
                close = 1;
                break;
 
            case SDL_KEYDOWN:
                // keyboard API for key pressed
                switch (event.key.keysym.scancode) {
                case SDL_SCANCODE_W:
                case SDL_SCANCODE_UP:
                    dest.y -= speed / 30;
                    break;
                case SDL_SCANCODE_A:
                case SDL_SCANCODE_LEFT:
                    dest.x -= speed / 30;
                    break;
                case SDL_SCANCODE_S:
                case SDL_SCANCODE_DOWN:
                    dest.y += speed / 30;
                    break;
                case SDL_SCANCODE_D:
                case SDL_SCANCODE_RIGHT:
                    dest.x += speed / 30;
                    break;
                default:
                    break;
                }
            }
        }
 
        // right boundary
        if (dest.x + dest.w > 1000)
            dest.x = 1000 - dest.w;
 
        // left boundary
        if (dest.x < 0)
            dest.x = 0;
 
        // bottom boundary
        if (dest.y + dest.h > 1000)
            dest.y = 1000 - dest.h;
 
        // upper boundary
        if (dest.y < 0)
            dest.y = 0;
 
        // clears the screen
        SDL_RenderClear(rend);
        SDL_RenderCopy(rend, tex, NULL, &dest);
 
        // triggers the double buffers
        // for multiple rendering
        SDL_RenderPresent(rend);
 
        // calculates to 60 fps
        SDL_Delay(1000 / 60);
    }
 
    // destroy texture
    SDL_DestroyTexture(tex);
 
    // destroy renderer
    SDL_DestroyRenderer(rend);
 
    // destroy window
    SDL_DestroyWindow(win);
     
    // close SDL
    SDL_Quit();
 
    return 0;
}

这将在窗口上渲染图像，可以通过键盘上下左右控制该图像。
输出：

参考文献： https : //www.libsdl.org/，https://github.com/vivek9236/rocket_game

要从最佳影片策划和实践问题去学习，检查了C++基础课程为基础，以先进的C++和C++ STL课程基础加上STL。要完成从学习语言到DS Algo等的更多准备工作，请参阅“完整面试准备课程” 。