Bearing calculation out of 2 nmea strings

[ScaleRobotics]

Sounds like a fine approach to me. The more complicated stuff is for if you want to know which direction and distance it is to something. If you just want to see if its been moved, and don't care which direction it's been moved to, it seems nice and simple.

[Art]

You should be able to cycle a list of waypoints,
measure the distance to all of them,
find the closest, calculate the bearing, and draw an arrow pointing to it.
Was that the idea?

I finally got PBP working with MPLab again today,
The trig functions should be fine to rotate points around a screen
(2D screen with X - Y coordinates) yes ?

This is how I'd rotate points about an origin in C, where 160x240 is the origin
this was to connect the points for a 3D cube, so has a faked z axis as well:

    // do pre-calculations for rotation
        theta = rotation;		// pre calculations
	thetab = 360 - theta;
	thetab = (3.141592 / 180) * theta;
	ztheta = rotationz;
	zthetab = 360 - ztheta;
	zthetab = (3.141592 / 180) * ztheta;    
    
    
	for(cnt=0; cnt<8; cnt++) {	// 3D rotate points
        xx = xpoints[cnt];
        yy = ypoints[cnt];
        x = xx - 160;
        y = yy - 240;
        xnew = cos(thetab)*x - sin(thetab)*y;
        ynew = sin(thetab)*x + cos(thetab)*y;
        xnew = xnew + 160;
        ynew = ynew + 240;
        if (cnt < 4) {zxx = 160 + 76;} else {zxx = 160 - 76;}
        zyy = ynew;
        zx = zxx - 160;
        zy = zyy - 240;
        zxnew = cos(zthetab)*zx - sin(zthetab)*zy;
        zynew = sin(zthetab)*zx + cos(zthetab)*zy;
        zxnew = zxnew + 160;
        zynew = zynew + 240;
        xcoords[cnt+1] = xnew;
        ycoords[cnt+1] = zynew;
	}

The source and return data is coordinate integers, but it appears the trick you do
is multiplying out the fractions in the formula is to occupy integers and divide later?

[Demon]

Art, I see you're catching up on some reading.

The last post was from August, 2 years ago.

Robert (being a smart-azz)

[Art]

It's cool, cordic trig would still be a good thing to get working.
I tried last time, and had no luck, but it's worth another shot.

Art, I see you're catching up on some reading.

The last post was from August, 2 years ago.

Robert (being a smart-azz)

[Art]

double post :O