SDL 渲染纹理

#include <windows.h>   // include important windows stuff

#include "SDL.h"

#include <cstdio>

#pragma comment(lib,"SDL2.lib")
#pragma comment(lib,"SDL2main.lib")

#pragma warning(disable:4244) //全部关掉

#define SCREEN_WIDTH 640            //窗口尺寸
#define SCREEN_HEIGHT 480

                                 
SDL_Window* gWindow = nullptr;//渲染的窗口


SDL_Surface* gScreenSurface = nullptr;//窗口包含的表面

SDL_Renderer* gRenderer = nullptr;


SDL_Texture* gTexture = nullptr;//加载和显示到屏幕的图像


UINT pixels[SCREEN_WIDTH * SCREEN_HEIGHT];

                                    
bool init();//启动sdl，创建窗口

void close();

int Game_Main();


void setPixels(int x, int y, UINT color);

int main(int argc, char *argv[])
{
    printf("Start Game!
");

    if (!init())
    {
        printf("Failed to initialize!
");
    }
    else
    {
        bool quit = false;

        SDL_Event e;

        while (!quit)
        {
            while (SDL_PollEvent(&e) != 0)
            {
                if (e.type == SDL_QUIT)
                {
                    quit = true;
                }
            }

            Game_Main();
        }
    }

    close();

    return 0;
}

bool init()
{
    bool success = true;

    if (SDL_Init(SDL_INIT_VIDEO) < 0)
    {
        printf("SDL could not initialize! SDL_Error: %s
", SDL_GetError());
        success = false;
    }
    else
    {
        gWindow = SDL_CreateWindow("sdl test", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
        if (gWindow == nullptr)
        {
            printf("Window could not be created! SDL_Error: %s
", SDL_GetError());
            success = false;
        }
        else
        {
            gRenderer = SDL_CreateRenderer(gWindow, -1, SDL_RENDERER_ACCELERATED);
            if (gRenderer == nullptr)
            {
                printf("Renderer could not be created! SDL_Error: %s
", SDL_GetError());
                success = false;
            }
            else
            {
                gScreenSurface = SDL_GetWindowSurface(gWindow);

                gTexture = SDL_CreateTexture(gRenderer, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_STATIC, SCREEN_WIDTH, SCREEN_HEIGHT);
            }
        }
    }

    return success;
}


void close()
{
    SDL_DestroyTexture(gTexture);
    gTexture = nullptr;

    SDL_DestroyRenderer(gRenderer);
    SDL_DestroyWindow(gWindow);
    gWindow = nullptr;
    gRenderer = nullptr;

    SDL_Quit();
}

void setPixels(int x, int y, UINT color) 
{
    int index = (int)(SCREEN_WIDTH * y + x);

    pixels[index] = color;
}


//游戏循环
int Game_Main()
{
    //清屏
    SDL_SetRenderDrawColor(gRenderer, 0xFF, 0xFF, 0xFF, 0xFF);
    SDL_RenderClear(gRenderer);

    //清空像素
    memset(pixels, 0xFF0000, SCREEN_WIDTH * SCREEN_HEIGHT * sizeof(Uint32));

    //设置像素点
    setPixels(10, 10, 0xFF0000);
    setPixels(20, 20, 0x00FF00);

    SDL_UpdateTexture(gTexture, NULL, pixels, 640 * sizeof(Uint32));

    //渲染贴图到屏幕
    SDL_RenderCopy(gRenderer, gTexture, nullptr, nullptr);

    //显示
    SDL_RenderPresent(gRenderer);

    return 1;
}