[C++知识库]纯C语言RGBA8888转ARGB1555格式

#define MICSIZE 10
#if 1

	FILE* fpbmp;
	FILE* fpout;
	unsigned char* pu8FileBuffer = NULL;
	fpbmp = fopen("xxx.rgba", "rb");

	if (fpbmp == NULL)
	{
		printf("Open bmp failed!!!\n");
	}
	else
	{
		printf("Open bmp success!!!\n");
	}

	fpout = fopen("1111.argb1555", "wb+");
	if (fpout == NULL)
	{
		printf("Open out.bmp failed!!!\n");
	}
	else
	{
		printf("Open out.bmp success!!!\n");
	}

	fseek(fpbmp, 0, SEEK_SET);  //定位原图 偏移位置
	fseek(fpout, 0, SEEK_SET);  //定位新图 偏移位置


	unsigned char u8bitAlphaChannel = 0;
	unsigned char u8bitRedChannel = 0;
	unsigned char u8bitGreenChannel = 0;
	unsigned char u8bitBlueChannel = 0;
	unsigned int alpha = 0;
	unsigned int red = 0;
	unsigned int green = 0;
	unsigned int blue = 0;
	unsigned short ARGB1555pixel= 0;


	pu8FileBuffer = (unsigned char*)malloc(MICSIZE * MICSIZE *4);
	if (pu8FileBuffer == NULL)
	{
		printf("malloc failed fileSize=%d\n", fpbmp);
		fclose(fpbmp);
		 
	}
	memset(pu8FileBuffer, 0, MICSIZE * MICSIZE *4);
	//fseek(pFile, 54, SEEK_SET);

	fread(pu8FileBuffer, 1, MICSIZE * MICSIZE *4, fpbmp);
	fclose(fpbmp);

	unsigned short* pBmpBufOut = NULL;
	pBmpBufOut = (unsigned short*)malloc(MICSIZE * MICSIZE * 2);
	memset(pBmpBufOut, 0, MICSIZE * MICSIZE * 2);



	for (int i = 0; i < MICSIZE * MICSIZE * 4; i+=4)
	{

		u8bitAlphaChannel = *(pu8FileBuffer + i + 3);
		u8bitRedChannel = *(pu8FileBuffer + i + 0);
		u8bitGreenChannel  = *(pu8FileBuffer + i + 1);
		u8bitBlueChannel = *(pu8FileBuffer + i + 2);

		alpha = (u8bitAlphaChannel + 127) / 255;
		red = (u8bitRedChannel * 31 + 127) / 255;
		green = (u8bitGreenChannel * 31 + 127) / 255;
		blue = (u8bitBlueChannel * 31 + 127) / 255;
		ARGB1555pixel = (alpha << 15) | (red << 10) | (green << 5) | blue;

		*(pBmpBufOut + i / 4) = ARGB1555pixel;
	}
	fwrite(pBmpBufOut, MICSIZE * MICSIZE, sizeof(unsigned short), fpout);

	fclose(fpout);
#endif