sdl实现texture旋转

  如果遇到闪退，尝试修改字体路径。

  利用函数 SDL_RenderCopyEx 可以实现texture旋转，函数参数 SDL_FLIP_NONE：无翻转，SDL_FLIP_HORIZONTAL：水平翻转，SDL_FLIP_VERTICAL：垂直翻转。

  

  效果图：

  代码：

#include <SDL2/SDL.h>
#include <SDL2/SDL_ttf.h>
//显示的texture的数量
const int TexNum =5;
SDL_Window*window=NULL;
SDL_Renderer*renderer=NULL;

//窗口类
class Window
{
    public:
    //记录是否加载成功
    bool load;
    //构造函数
    Window(char title[20], Uint32 w=720, Uint32 h=1280, int flag=0)
   {
        load=false;
        if (!SDL_Init(SDL_INIT_VIDEO))
        if (window=SDL_CreateWindow(title, 0, 0, w, h, flag))
        if (renderer=SDL_CreateRenderer(window, -1, 0))
        {
            //加载窗口成功
            load=true;
        }
    }
    
    //析构函数
    ~Window()
    {
SDL_DestroyRenderer(renderer);
SDL_DestroyWindow(window);
SDL_Quit();
    }

    //填充窗口：白色
    void fullWindow()
    {
SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
SDL_RenderFillRect(renderer, NULL);
    }

    //刷新窗口
    void reflush()
    {
SDL_RenderPresent(renderer);
SDL_RenderClear(renderer);
    }
};

//文字类
class Font
{
    public:
    TTF_Font*font; 
    //构造函数:size为字体大小
    Font(int size=70)
    {
        TTF_Init();
font=TTF_OpenFont("./resource/DroidSansFallback.ttf", size);
    }

    //析构函数
    ~Font()
    {
        TTF_CloseFont(font);
        font=0;
        TTF_Quit();
    }

    //把文字加载成texture
SDL_Texture*loadTex(char*str, int type=4)
    {
        switch (type)
        {
            case 0:TTF_SetFontStyle(font,TTF_STYLE_BOLD);break; //粗体
            case 1:TTF_SetFontStyle(font,TTF_STYLE_ITALIC);break; //斜体
            case 2:TTF_SetFontStyle(font,TTF_STYLE_UNDERLINE);break; //下划线
            case 3:TTF_SetFontStyle(font,TTF_STYLE_STRIKETHROUGH);break; //删除线
            case 4:TTF_SetFontStyle(font,TTF_STYLE_NORMAL);break; //正常
        }

        //文字颜色：黑色
        SDL_Color color={0, 0, 0, 255};
        
SDL_Surface*surface=TTF_RenderUTF8_Blended(font, str, color);

SDL_Texture*texture=SDL_CreateTextureFromSurface(renderer, surface);

SDL_FreeSurface(surface);
        return texture;

    }

};

//纹理类
class Tex
{
    public:
    SDL_Texture*tex[TexNum];
    SDL_Rect box[TexNum];
    Font font;
    //特效texture
    SDL_Texture*texture;
    SDL_Rect TexBox;
    int angle=0;  //角度
    int type=0;
    //构造函数
    Tex()
    {
        char *str[TexNum]={"开始旋转", "暂停旋转", "左右翻转", "上下翻转", "退出"}; 
        for (int i=0; i<TexNum; i++)
        {
tex[i]=font.loadTex(str[i]);
        int w,h;
//获取纹理大小
        SDL_QueryTexture(tex[i], NULL, NULL, &w, &h);
//设置纹理的大小
        box[i].w=w;
        box[i].h=h;
        }
//设置纹理的坐标
        box[0].x=50;
        box[0].y=800;
        box[1].x=400;
        box[1].y=800;
        box[2].x=50;
        box[2].y=950;
        box[3].x=400;
        box[3].y=950;
        box[4].x=280;
        box[4].y=1100;
//设置特效texture
Font BigFont(150);
texture=BigFont.loadTex("texture");
        int w,h;
//获取纹理大小
        SDL_QueryTexture(texture, NULL, NULL, &w, &h);
TexBox.w=w;
TexBox.h=h;
    }

    //析构函数
    ~Tex()
    {
        for (int i=0; i<TexNum; i++)
        {
            if (tex[i]!=NULL)
       SDL_DestroyTexture(tex[i]);
        }
SDL_DestroyTexture(texture);
    }
    //显示tex
    void showTex(int n)
    {
SDL_RenderCopy(renderer, tex[n], NULL, &box[n]);
    }
//显示特效texture
void showTexture(int x=100, int y=250)
{
TexBox.x=x;     TexBox.y=y;
SDL_Point point={TexBox.w/2, TexBox.h/2};
switch (type)
{
case 0:SDL_RenderCopyEx(renderer,texture,NULL,&TexBox,angle,&point,SDL_FLIP_NONE);break;//无翻转
case 1:SDL_RenderCopyEx(renderer,texture,NULL,&TexBox,angle,&point,SDL_FLIP_HORIZONTAL);break;//水平翻转
case 2:SDL_RenderCopyEx(renderer,texture,NULL,&TexBox,angle,&point,SDL_FLIP_VERTICAL);break;//垂直翻转
}
	}
};

//按钮类
class Button
{
    SDL_Event event;
    SDL_Rect box[TexNum];
    //屏幕分辨率
    int win_w,win_h;
	public :
	Tex tex;
	int m=-1; //按下和移动时按钮索引
	int n=-1;  //抬起时按钮索引
	int nn=-1; //n的上一个值
	//构造函数
	Button()
	{
		//获取屏幕分辨率
SDL_GetWindowSize(window, &win_w, &win_h);
		//获取tex文字大小和坐标
		for (int i=0; i<TexNum; i++)
		{
			box[i].x=tex.box[i].x;
			box[i].y=tex.box[i].y;
			box[i].w=tex.box[i].w;
			box[i].h=tex.box[i].h;
			}
		}
	void touch()
	{
			while (SDL_PollEvent(&event))
		{
			switch (event.type)
			{
//手指按下
case SDL_FINGERDOWN:
//手指滑动
case SDL_FINGERMOTION:{
	//event.tfinger.x和event.tfinger.y值范围：0~1
SDL_Point point={event.tfinger.x*win_w, event.tfinger.y*win_h};
for (int i=0; i<TexNum; i++)
//判断触点是否在box矩形中中
if (SDL_PointInRect(&point, &box[i]))
m=i;
	}break;
//手指抬起
				case SDL_FINGERUP:{
//event.tfinger.x和event.tfinger.y值范围：0~1
SDL_Point point={event.tfinger.x*win_w, event.tfinger.y*win_h};
for (int i=0; i<TexNum; i++)
//判断触点是否在box矩形中
if (SDL_PointInRect(&point, &box[i]))
n=i;
m=-1;
					}break;
				}
			}
		}
	void show()
	{
		//绘画填充矩形
		for (int i=0; i<TexNum; i++)
		{
SDL_SetRenderDrawColor(renderer, 0, 255, 255, 0);
SDL_RenderFillRect(renderer, &box[i]);
			}
		if (m!=-1)
		{
SDL_SetRenderDrawColor(renderer, 255, 0, 0, 0);
SDL_RenderFillRect(renderer, &box[m]);	
			}	
			//显示文字
			for (int i=0; i<TexNum; i++)
			tex.showTex(i);
		}
	};

//主函数
int main(int argc, char**argv)
{
    Window win("多个按钮");
    Button button;
    while (win.load)
    {
    	button.touch();
    	button.show();
    	switch (button.n)
    	{
    		case -1:{
button.tex.showTexture();
    			}break;
    			case 0:{
button.tex.angle++;
button.tex.showTexture();
    				}break;
    			case 1:{
button.tex.showTexture();					
    					}break;
    			case 2:{
button.tex.type=1;
button.tex.showTexture();						
    						}break;
    			case 3:{
button.tex.type=2;
button.tex.showTexture();					
    						}break;
    		        case 4:{
    			win.load=false;
    			}break;
    		}
        win.reflush();
        win.fullWindow();
        button.nn=button.n;
    }
    }