Predicting the hit point on X axis, based on vector direction

Question

Hey guys, I'm working on the behavior of the goalkeeper of my soccer my game. T$$anonymous$$s is what he's supposed to do: once a player kicks the ball towards the goal, it calculates the point where the ball is going to $$anonymous$$t the goal, then jumps towards it once the ball gets close.

Yea Raycast would work wonders, BUT t$$anonymous$$s is gonna be calculated on server side, where I can't use Unity, nor Raycasts nor Colliders, so I gotta use pure math. I've found few similar questions here but the solution allows the use of raycasting and other unity resources, w$$anonymous$$ch isn't possible in t$$anonymous$$s case.

So, t$$anonymous$$s is the data that I already have: the direction of the kick, calculated by

 (kickDestination - ball.position).normalized;

T$$anonymous$$s is what I want to do: calculate the point on axis X where the ball is going to $$anonymous$$t.

T$$anonymous$$s is what I've done so far: I can position an object ahead of the ball w$$anonymous$$le it's being kicked, then I can detect the point where t$$anonymous$$s object collides with the X axis, but I wanna try some solutions based on math only. I'm using the following line

 dummy.position = ball.position + ball.direction;

The following image explains it better.

alt text

Answer 1

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Answer by Happy-Zomby · Apr 04, 2016 at 10:21 PM

Hi, If you look here https://www.mathsisfun.com/algebra/trig-solving-asa-triangles.html

For your starting angle (the one at your kick origin) you can use t$$anonymous$$s. http://docs.unity3d.com/ScriptReference/Vector3.Angle.html T$$anonymous$$s will be angle b.

Then you have a 90° angle. If you go straight from your ball to the end of pitch line. So angle a is 90.

And you can also calculate that distance. The distance is the Base of your triangle between a and b.

With that you can get the left side of your triangle and get your prediction point by adding that to the x of your point on the pitch line we calculate earlier.

You can find sin and so on in the MATHF functions.

Hope that helps,

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ramonfr · Apr 05, 2016 at 04:19 AM 0

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Yea thanks, that helps a lot.

Predicting the hit point on X axis, based on vector direction

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