SDL2.0的几何图行绘画

SDL2.0的几何图形绘画

 

通过SDL_Window、SDL_Renderer、SDL_Texture三者实现了简单的几何图形绘画。

包括了SDL_RenderDrawPoint、SDL_RenderFillRect、SDL_RenderDrawLine、SDL_SetRenderDrawColor等。

具体看代码吧（VS2012运行）：

#include <stdio.h>
#include <string.h>
#include <time.h>
#include <SDL2\SDL.h>
#include <SDL2\SDL_image.h>
#include <SDL2\ex\SDLex.h>

SDL_Window *sdlWindow = NULL;
SDL_Renderer *sdlRender = NULL;
SDL_Texture *sdlTexture = NULL;
SDL srcRect;
int w = 500;
int h = 500;

void DrawCircle(SDL_Renderer *ren,int radius){
    int st=clock(),tx=0,ty=radius,d=3-(radius<<1),x=radius,y=radius;
    while(tx<ty){
        for (int i=x-ty;i<=x+ty;++i){
            SDL_RenderDrawPoint(ren,i,y-tx);
            if (tx)
                SDL_RenderDrawPoint(ren,i,y+tx);
        }
        if (d<0)
            d+=(tx<<2)+6;
        else{
            for (int i=x-tx;i<=x+tx;++i){
                SDL_RenderDrawPoint(ren,i,y-ty);
                SDL_RenderDrawPoint(ren,i,y+ty);
            }
            d+=((tx - ty)<<2)+10,ty--;
        }
        tx++;
    }
    if (tx==ty)
        for (int i=x-ty;i<=x+ty;++i){
                SDL_RenderDrawPoint(ren,i,y-tx);
                SDL_RenderDrawPoint(ren,i,y+tx);
        }
    int en=clock();
}

bool InitView(int width, int height, const char *iconName)
{
    //初始化窗体
    SDL_Init(SDL_INIT_VIDEO);

    sdlWindow = SDL_CreateWindow(
        "The First SDL Program", 
        SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, width, height, 
        SDL_WINDOW_RESIZABLE);
    if (sdlWindow == NULL) return false;

    //加载窗体图标
    SDL_Surface *iconSurface = IMG_Load(iconName);
    if (iconSurface == NULL) return false;

    SDL_SetWindowIcon(sdlWindow, iconSurface);

    return true;
}

bool InitDraw()
{
    //加载渲染器
    sdlRender = SDL_CreateRenderer(sdlWindow, -1, 0);
    if (sdlRender == NULL) return false;

    sdlTexture = SDL_CreateTexture(sdlRender, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_TARGET, w, h);
    if (sdlTexture == NULL) return false;
    //SDL_SetTextureBlendMode(sdlTexture, SDL_BLENDMODE_BLEND);
    //SDL_SetRenderTarget(sdlRender, sdlTexture);

    return true;
}

void UpdateDraw()
{
    //设置背景颜色
    SDL_SetRenderDrawColor(sdlRender, 255, 153, 153, 0xFF);
    SDL_RenderClear(sdlRender);
    
    //左眼
    SDL_SetRenderDrawColor(sdlRender, 0x00, 0xFF, 0xFF, 0xFF);
    srcRect = SDLMake(w/7*2, h/7, w/8, h/8);
    SDL_RenderFillRect(sdlRender, &srcRect);
    
    //左眉毛
    SDL_SetRenderDrawColor(sdlRender, 0x00, 0x00, 0x00, 0xFF);
    SDL_RenderDrawLine(sdlRender, srcRect.x, srcRect.y - 10, SDLMaxX(srcRect), srcRect.y - 10);
    
    //右眼
    SDL_SetRenderDrawColor(sdlRender, 0xFF, 0x00, 0xFF, 0xFF);
    srcRect = SDLMake(w/7*4, srcRect.y, srcRect.w, srcRect.h);
    SDL_RenderDrawRect(sdlRender, &srcRect);
    
    //右眉毛
    SDL_SetRenderDrawColor(sdlRender, 0x00, 0x00, 0x00, 0xFF);
    SDL_RenderDrawLine(sdlRender, srcRect.x, srcRect.y - 10, SDLMaxX(srcRect), srcRect.y - 10);
    
    //嘴巴
    SDL_SetRenderDrawColor(sdlRender, 0xFF, 0xFF, 0x00, 0xFF);
    srcRect = SDLMake(w/8*3, h/7*3, w/8*2, h/8);
    SDL_RenderFillRect(sdlRender, &srcRect);
    
    SDL_SetRenderDrawColor(sdlRender, 0xFF, 0x00, 0x00, 0xFF);
    DrawCircle(sdlRender, 10);
    
    SDL_RenderPresent(sdlRender);
}

void Quit(int code)
{
    const char *errMsg = SDL_GetError();
    if (errMsg && strlen(errMsg)) {
        SDL_Log("Error : %s\n", errMsg);
    }

    //销毁窗口、渲染器、纹理
    if (sdlWindow) SDL_DestroyWindow(sdlWindow);
    if (sdlRender) SDL_DestroyRenderer(sdlRender);
    if (sdlTexture) SDL_DestroyTexture(sdlTexture);
    SDL_Quit();
    exit(code);
}

void HandleKeyEvent(const SDL_Keysym* keysym)
{
    int key = keysym->sym;
    switch(key)
    {
    case SDLK_ESCAPE:
        Quit(0);
        break;
    case SDLK_SPACE:
        break;
    case SDLK_UP:
    case SDLK_DOWN:
    case SDLK_LEFT:
    case SDLK_RIGHT:
        int x, y;
        SDL_GetWindowPosition(sdlWindow, &x, &y);
        x = (key == SDLK_LEFT ? x-2 : (key == SDLK_RIGHT ? x+2 : x));
        y = (key == SDLK_UP ? y-2 : (key == SDLK_DOWN ? y+2 : y));
        SDL_SetWindowPosition(sdlWindow, x, y);
        SDL_Log("x=%d, y=%d\n", x, y);
        break;
    case SDLK_KP_PLUS:
    case SDLK_KP_MINUS:
        w = (key == SDLK_KP_PLUS ? w+2 : w-2);
        h = (key == SDLK_KP_PLUS ? h+2 : h-2);
        SDL_SetWindowSize(sdlWindow, w, h);
        SDL_Log("w=%d, h=%d\n", w, h);
        break;
    default:
        break;
    }
}

void HandleEvents()
{
    //Our SDL event placeholder.
    SDL_Event event;
    //Grab all the events off the queue.
    while(SDL_PollEvent(&event)) {
        switch(event.type) {
        case SDL_KEYDOWN:
            //Handle key Event
            HandleKeyEvent(&event.key.keysym);
            break;
        case SDL_QUIT:
            //Handle quit requests (like Ctrl-c).
            Quit(0);
            break;
        }
    }
}

int main(int argc, char* argv[])
{
    printf("可以通过↑↓←→+ -按键控制移动和大小\n");
    if (InitView(w, h, "yp.ico") == false) {
        SDL_Log("sdlWindow is null @_@\n");
        Quit(0);
        return -1;
    }

    if (InitDraw() == false) {
        SDL_Log("Init Fail @_@\n");
        Quit(0);
        return -1;
    }
    
    //配置客户区大小
    SDL_QueryTexture(sdlTexture,NULL, NULL, &w, &h);
    SDL_SetWindowSize(sdlWindow, w + 2, h);
    SDL_Log("w=%d, h=%d\n", w, h);
    
    while (1) {
        HandleEvents();
        UpdateDraw();
    }
    
    SDL_DestroyWindow(sdlWindow);
    SDL_Quit();
    return 0;
}

效果图：