Screen Shots

  
void Screenshot()
{
	char currFileName[30];   // array to build the filename

	unsigned char r = 0, g = 0, b = 0; // RGB values to build the bitmap

	
	BITMAPFILEHEADER fileHeader;
	BITMAPINFOHEADER infoHeader;
	unsigned char* bitmapBits = NULL;
	
	// allocate the bits, 3 bytes per pixel (24 bits), the size of the screen

	bitmapBits = new unsigned char[SCREEN_WIDTH * SCREEN_HEIGHT * 3];
	if(bitmapBits == NULL)
	{
		DebugOut("-Screenshot: Failed to allocate bitmap bits.\n");
		return;
	}

	// copy the screen data to the bitmap


	backBuffer->Lock(NULL,&desc,DDLOCK_WAIT | DDLOCK_SURFACEMEMORYPTR | SYSLOCK_FLAG,NULL);

	unsigned short* videoBuffer = (unsigned short*)desc.lpSurface;

	for(int i = 0, j = 0; i < SCREEN_HEIGHT; i++, videoBuffer += pixelLPitch)
		for(int col = 0; col < SCREEN_WIDTH; col++, j += 3)
		{
			ExtractRGB(videoBuffer[col],&r,&g,&b);

			// scale the color components up to 8 bits per color levels

			r *= 8;
			g *= gScale;
			b *= 8;

			// save them in reverse order

			bitmapBits[j] = b;
			bitmapBits[j + 1] = g;
			bitmapBits[j + 2] = r;
		}

	backBuffer->Unlock(NULL);

	// build the headers

	fileHeader.bfType = ''MB''; // MB instead of BM because of intel byte order

	fileHeader.bfSize = (sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) +
								(SCREEN_WIDTH * SCREEN_HEIGHT * 3));
	fileHeader.bfReserved1 = 0;
	fileHeader.bfReserved2 = 0;
	fileHeader.bfOffBits = (sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER));

	infoHeader.biSize = sizeof(BITMAPINFOHEADER);
	infoHeader.biWidth = SCREEN_WIDTH;
	infoHeader.biHeight = SCREEN_HEIGHT;
	infoHeader.biPlanes = 1;
	infoHeader.biBitCount = 24;
	infoHeader.biCompression = BI_RGB;
	infoHeader.biSizeImage = (SCREEN_WIDTH * SCREEN_HEIGHT * 3);
	infoHeader.biXPelsPerMeter = 0;
	infoHeader.biYPelsPerMeter = 0;
	infoHeader.biClrUsed = 0;
	infoHeader.biClrImportant = 0;

	// generate a filename for the bitmap file

	i = 0;
	while(true)
	{		
		wsprintf(currFileName,"Inv2Shot%d.bmp",i);

		// check if the current file name is available

		// (if _access returns -1, then the file doesn''t exist)

		if(_access(currFileName,0) == -1)
			break;

		i++;
	}

	// flip the bitmap (they''re stored upside-down)

	unsigned char* picture; // new byte pointer to the bitmap buffer

	unsigned char* tempBuffer; // a temporary buffer


	picture = bitmapBits;
	tempBuffer = new unsigned char[SCREEN_WIDTH * SCREEN_HEIGHT * 3];
	if(tempBuffer == NULL)
	{
		DebugOut("-ScreenShot: Failed to allocate temp buffer for flipping.\n");
		delete[] bitmapBits;
		bitmapBits = NULL;
		return;
	}

	memcpy(tempBuffer,picture,(SCREEN_WIDTH * SCREEN_HEIGHT * 3));

	for(i = 0; i < SCREEN_HEIGHT; i++)
		memcpy(&picture[((SCREEN_HEIGHT - 1) - i) * (SCREEN_WIDTH * 3)],
			&tempBuffer[i * (SCREEN_WIDTH * 3)], SCREEN_WIDTH * 3);

	delete[] tempBuffer;

	// write it all to a file

	FILE* file = fopen(currFileName,"wb");

	fwrite(&fileHeader,sizeof(BITMAPFILEHEADER),1,file);
	fwrite(&infoHeader,sizeof(BITMAPINFOHEADER),1,file);
	fwrite(bitmapBits,SCREEN_WIDTH * SCREEN_HEIGHT * 3,1,file);

	fclose(file);

	// deallocate the bitmap

	if(bitmapBits)
		delete[] bitmapBits;
}