Problem reading from bitmap

[mike_g]

I'm making a prog that converts a bitmap to a kind of binary stencil.

The data that gets written is the image width, followed by a bool signaling if the first pixel is on or not. The data after that is written as a sequence of short values each saying how many pixels to draw or skip.

My problem is that only 3 bytes are being written to the file and the on-off states never seem to flip. I added some debug output and it displays the first pixel on my bmp to have a value of 2293488 when it is black and should be 0.

The problem should be in the highlighted area. Also to test it there needs to be a 24bit bitmap image in the same directory called "test.bmp".

#include <iostream>
#include <fstream>
using namespace::std;
bool Convert(const char*, const char*);

int main()
{
    if(! Convert("test.bmp", "result.dat"))
        cout << "Error";
    else
        cout << "Success";
    cin.ignore();
}

// Converts 24bit bmp data to compressed format
bool Convert(const char* bmpFile, const char* outFile)
{	
	short w, h;
	char bytes[3];
        bool state;
	int count =0;

	//Set up streams
	ifstream in;
	ofstream out;
	in.open(bmpFile, ios::binary);
	if(! in.is_open()) return false;
	out.open(outFile, ios::out);

	//Write the image width
	in.seekg(18, ios::beg);
	in.read((char *)&w, sizeof w);
	in.seekg(22, ios::beg);
        out.write(bytes, 2);
	in.read((char *)&h, sizeof h);
        cout << "Width: " << w << endl;
        cout << "Height: " << h << endl;

	//Write if first pixel is on or not
	in.seekg(54,ios::beg);
	in.read(bytes, 3);
	
        if(bytes)
                state = true;
	else
		state = false;

        out.write((char*)&state, 1);
        cout << "Pix 1: " << ((int)bytes & 0x00FFFFFF) << endl;
        cout << "State: " << state << endl;

	in.seekg(54, ios::beg);
	for(int y=h; y>0; y--)
	{
		for(int x=0; x<w; x++)
		{		
			in.read((char*)&bytes, 3);          
			if(state)
			{
				if(bytes)	
				{
					count++;
				}
				else
				{					
					out.write((char*)&count, 2);		
                                        cout << "On: " << count << endl;
                                        count = 1;
                                        state = false;
				}
			}
			else
			{
				if(!bytes)
				{
					count++;
				}
				else
				{					
					out.write((char*)&count, 2);
                                        cout << "Off: " << count << endl;
					count = 1;
                                        state = true;
				}
			}
		}
	}
        cout << "Counter at: " << count << endl;
	in.close();
        out.close();
	return true;
}/**/

Cheers.

[oogabooga]

Hi mike, testing "bytes" will always be true since bytes is an array and evaluates to its address.
Maybe something like this. It should do for testing for zero.

unsigned pix = 0; // ensure all 4 (or more!) bytes start as zero
in.read( (char*)&pix, 3 );
if (pix)
 ...

[mike_g]

Yep, that looks like it fixed it. Thanks