SDL2.0 扣色（PNG图片重叠）

两张png图片叠加在一起,使用SDL让前景色透明

#include “stdafx.h“
#include “include/SDL.h“
#include “SDL2_image/include/SDL_image.h“
#pragma comment（lib “lib/x86/SDL2.lib“）
#pragma comment（lib “SDL2_image/lib/x86/SDL2_image.lib“）

int _tmain（int argc _TCHAR* argv[]）
{
	SDL_Init（SDL_INIT_EVERYTHING）;//SDL初始化

	SDL_Window *Screen = SDL_CreateWindow（“title“ 100 100 640 480 SDL_WINDOW_RESIZABLE）;//创建窗口
	SDL_Renderer *render = SDL_CreateRenderer（Screen -1 0）;//创建渲染器
	SDL_Surface *bk = IMG_Load（“F:\\background.png“）;//SDL IMAGE扩展库读取tga图片
	SDL_Surface *foo = IMG_Load（“F:\\foo.png“）;//SDL IMAGE扩展库读取tga图片

	//Use this function to map an RGB triple to an opaque pixel value for a given pixel format
	//format:an SDL_PixelFormat structure describing the format of the pixel
	Uint32 colorkey = SDL_MapRGB（foo->format 0x00 0xff 0xff）;//用画图工具提取foo.png的背景颜色发现foo.png的背景色是0x00ffff


	//surface:the SDL_Surface structure to update
	//flag:SDL_TRUE to enable color key SDL_FALSE to disable color key
	//key:the transparent pixel
	//Returns 0 on success or a negative error code on failure; call SDL_GetError（） for more information.
	SDL_SetColorKey（foo 1 colorkey）;//Use this function to set the color key （transparent pixel） in a surface.

	SDL_Texture *texture = SDL_CreateTextureFromSurface（render bk）;//创建纹理
	SDL_Texture *texture1 = SDL_CreateTextureFromSurface（render foo）;//创建纹理

	SDL_RenderClear（render）;
	SDL_RenderCopy（render texture NULL NULL）;//拷贝数据显示

	SDL_Rect rect;
	rect.x = 50;
	rect.y = 125;
	rect.w = foo->w;
	rect.h = foo->h;
	SDL_RenderCopy（render texture1 NULL &rect）;//拷贝数据显示
	SDL_RenderPresent（render）;

	SDL_Event event;
	while （1）{
		SDL_PollEvent（&event）;
		if （event.type == SDL_QUIT）{
			break;
		}
	}

	SDL_FreeSurface（bk）;//是否图片资源
	SDL_DestroyTexture（texture）;//释放纹理
	SDL_DestroyRenderer（render）;//释放渲染器
	SDL_DestroyWindow（Screen）;//销毁窗口
	SDL_Quit（）;//退出
	return 0;
}

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----

     文件       3718  2005-06-17 19:30  SDL_Lesson1\Debug\bk.png

     文件        548  2005-06-17 19:30  SDL_Lesson1\Debug\foo.png

     文件     223232  2016-01-02 21:52  SDL_Lesson1\Debug\libjpeg-9.dll

     文件     200704  2016-01-02 21:52  SDL_Lesson1\Debug\libpng16-16.dll

     文件     436224  2016-01-02 21:52  SDL_Lesson1\Debug\libtiff-5.dll

     文件     271872  2016-01-02 21:52  SDL_Lesson1\Debug\libwebp-4.dll

     文件    1068544  2016-10-19 20:58  SDL_Lesson1\Debug\SDL2.dll

     文件      93184  2016-01-02 21:52  SDL_Lesson1\Debug\SDL2_image.dll

     文件      32768  2017-06-22 13:38  SDL_Lesson1\Debug\SDL_Lesson1.exe

     文件     123904  2016-01-02 21:52  SDL_Lesson1\Debug\zlib1.dll

     文件       4182  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\begin_code.h

     文件       1417  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\close_code.h

     文件       4101  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL.h

     文件      10860  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_assert.h

     文件       9458  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_atomic.h

     文件      28133  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_audio.h

     文件       2527  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_bits.h

     文件       2252  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_blendmode.h

     文件       1966  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_clipboard.h

     文件       5722  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_config.h

     文件       4181  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_cpuinfo.h

     文件      73519  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_egl.h

     文件       5944  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_endian.h

     文件       2271  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_error.h

     文件      28067  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_events.h

     文件       5255  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_filesystem.h

     文件      10824  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_gamecontroller.h

     文件       2157  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_gesture.h

     文件      38621  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_haptic.h

     文件      32393  2016-10-19 20:59  SDL_Lesson1\SDL_Lesson1\include\SDL_hints.h

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