iOS Calculating triangle angle

[TodVader]

Hi. I'm not too sure about the technical words since I speak french but I have a rectangle triangle (with a 90degree angle).

I know both sides (x,y) so to get the hypothenuse, I did this:

float hyp = sqrt((difX * difX) + (difY * difY));

Now, to get the angle I want, I did this:

float rocketAngle = acos(difX/hyp); // difX/hyp should give me the cos of my angle.

I don't understand why it doesn't work. I apply a rotation to my missile with the angle of rocketAngle and it stays straight. My rotation code works if I test it with a static number.

This is done with OpenGL btw.

 

[-aggie-]

Not sure how you're using the rocket angle, but it's probably a degrees to radians issue. acos gives the angle in radians.

 

[TodVader]

Nice! Thankyou, that is probably the problem right there. I will go try this.

 

[PhoneyDeveloper]

That's called a right triangle.

The c library math functions work with radians, not degrees.

 

[TodVader]

Thankyou for the clarification. In french its a "Triangle rectangle"

Btw, this worked perfectly, I can now move on to different things.

Thanks for the help!

I just did (Radian*180)/PI

 

[-aggie-]

Thankyou for the clarification. In french its a "Triangle rectangle"

Btw, this worked perfectly, I can now move on to different things.

Thanks for the help!

Glad to help. I thought of writing my response en francais, but then no one else would know what I wrote. 🙂

Au revoir!