Targeting point

[Jackson Marie]

I have to do some calculations.

In short, the math exercise is :

Double xCurrentPt, yCurrentPt;
Double xTargetPt, yTargetPt;
Double angle;

Suppose a man is standing at position xCurrentPt, yCurrentPt and with angle "Angle". Now he want to move to position xTargetPt, yTargetPt. Before walking he must rotate himself to a proper angle value. He'll continue to walk with his speed 'fSpeed' until he's reached the Target position (xTargetPt, yTargetPt)

The problem is I can't get the new right angle when the target has been changed.
Eg :

xCurrentPt = 200;
yCurrentPt = 250;
Angle = 72º

Target :
xTargetPt : 125;
yTargetPt : 865;
Angle : ???????????

How to get the angle (or radian) between the current point and the target point? What the function is used to do this? Help please...

[AleaIactaEst]

This might help you: http://en.wikipedia.org/wiki/Triangle#Computing_the_sides_and_angles

As the length of the triangle sides you should use the x and y distance of the man to the target. For example:

double horizontalLine = xTargetPt - xCurrentPt;
double verticalLine = yTargetPt - yCurrentPt;

Now all you need to do is to calculate the angle between those two lines (think of it as a triangle, which means, connect the end of the horizontalLine with the end of the verticalLine). It probably helps to make a sketch.

By the way: You get all the trigonometric functions you need through the cmath ( http://www.cplusplus.com/reference/clibrary/cmath/ ) library.