Sine wave at an angle?

[Joe123]

At the moment, I have a movement routine for an enemy worked out to follow a straight line between two points, using y = mx +c.

I want to make it also move in a sine wave sort of pattern, but along that line...

I can only think of how to make things move in a sine wave along a horizontal or vertical line though.

Anyone have any ideas as to how I'd go about doing this?

[Saffith]

Just think of the wave movement as an offset along a line perpendicular to the direction you're moving. Something like this:

while(true)
{
    // Undo previous frame's offset
    this->X-=offset*Cos(angle+90);
    this->Y-=offset*Sin(angle+90);
    
    // Move along the overall angle
    this->X+=speed*Cos(angle);
    this->Y+=speed*Sin(angle);
    
    // Find the offset from the straight line
    offset=amplitude*Sin(i);
    
    // Offset movement
    this->X+=offset*Cos(angle+90);
    this->Y+=offset*Sin(angle+90);
    
    i=(i+1)%360;
    Waitframe();
}

[Joe123]

I shall...

...have a look and try to decipher that.

Thanks ^_^

[Joe123]

Oh, I had it moving using y=mx+c to move it along the line, but this uses sine and cosine to do that, doesn't it?

Hrm ok.



EDIT: With a little fiddling, and a complete conversion to radians it now works ^_^
Thanks.