Trigonometry | SpigotMC | Page 1

tawdry creek Mar 13, 2022, 1:49 PM

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I suck at trigonometry, help plz c:

eager seal Mar 13, 2022, 1:50 PM

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so you know the coords of the point and the location of the player

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imagine building a right triangle with the hypothenuse being the segment between the player and the point

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you need to get the angle between the hypothenuse and one of the sides of the triangle

tawdry creek Mar 13, 2022, 1:51 PM

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Will reiterate; I have a BukkitRunnable that will iterate over the players in the game and I intend on having a Set of players (so no duplicates) where whenever a player has their line of sight towards the ability activator with a configurable offset, they will be added to the set, it will then force everyone in the set to look at the activator until the ability ends

eager seal Mar 13, 2022, 1:52 PM

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so any player in the Set have to look at a point for a while

tawdry creek Mar 13, 2022, 1:52 PM

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Yeah that's right, in which case that point might change (if the activator moves)

eager seal Mar 13, 2022, 1:52 PM

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with need to i mean the plugin has to force them to

tawdry creek Mar 13, 2022, 1:53 PM

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Yeah, I know I'll have to somehow calculate the yaw/pitch to use and just constantly teleport them to their same x/y/z cords (as I want them to be able to move still)

eager seal Mar 13, 2022, 1:53 PM

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ok so imagine the blue dot is the player and the red one is the activator

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you need to get alpha (yellow angle)

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right?

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by definition, sin(alpha) = side of the triangle opposing the angle / hypothenuse

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in this case the side opposing alpha is the shortest one

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and the hypothenuse is the distance between the player and the point

tawdry creek Mar 13, 2022, 1:55 PM

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Yeah, I already have a formula to work out the hypothenuse

eager seal Mar 13, 2022, 1:55 PM

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you can just call .distance from Location

tawdry creek Mar 13, 2022, 1:56 PM

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Oh, guess I just recreated that for no reason then lol but anyway

eager seal Mar 13, 2022, 1:56 PM

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i'd suggest using distanceSquared since computing a square root is expensive

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since the distance you calculate with pythagoras' theorem

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which i guess you know

tawdry creek Mar 13, 2022, 1:57 PM

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Yeah

eager seal Mar 13, 2022, 1:57 PM

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so basically you can get the distance squared by running a^2 + b^2

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and not computing the sqrt

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because it's expensive

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and to compensate you square the other side too (the height of the triangle)

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do you know the 3 theorems of similar triangles? (not sure of the english name)

tawdry creek Mar 13, 2022, 1:58 PM

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In that case on another note, if I wanted to see if a player is within the radius of a location, would it work and be most efficient to compare distanceSquared vs radius^2?

eager seal Mar 13, 2022, 1:58 PM

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yes

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very noticeable if you need to iterate the Set

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and execute it often

tawdry creek Mar 13, 2022, 1:59 PM

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That's good to know, thank you. Now how can we use distance squared to get the yaw and pitch?

eager seal Mar 13, 2022, 1:59 PM

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eager seal do you know the 3 theorems of similar triangles? (not sure of the english name)

.

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basically you can extrapolate from them that if you square all of the sides of the triangle, the angles don't change

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so we can compute the sin without having to use sqrt

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so we can do sin(alpha) = height^2 / distance^2

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then if you compute the asin of that value, you get the angle

tawdry creek Mar 13, 2022, 2:04 PM

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So I should manually calculate the hypotenuse of the angle and disregard y then calculate the hypotenuse again after knowing the angle?

eager seal Mar 13, 2022, 2:05 PM

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no, you need to calculate the distance (which you have)

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and the height (which is the difference between the x values of the coords)

tawdry creek Mar 13, 2022, 2:08 PM

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So I'd get 1 of the angles from the sin of the (difference in y)^2 / distance^2 then the other angle from the difference in x^2/ distance^2?

eager seal Mar 13, 2022, 2:08 PM

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i'm talking about 2 dimensions still here so try that first

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then yea i think that could work

copper bolt Mar 13, 2022, 2:08 PM

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what the fuckius

eager seal Mar 13, 2022, 2:09 PM

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trigonometry

copper bolt Mar 13, 2022, 2:09 PM

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I'm too dumb to understand

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Goodbye

eager seal Mar 13, 2022, 2:09 PM

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cya

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lol

tawdry creek Mar 13, 2022, 2:09 PM

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Knew I should've paid more attention in school

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I enjoyed algebra and solving problems but always sucked at both geometry and trigonometry

eager seal Mar 13, 2022, 2:10 PM

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i actually have not studied this stuff in school yet

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i kinda taught them to myself

copper bolt Mar 13, 2022, 2:11 PM

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tawdry creek I enjoyed algebra and solving problems but always sucked at both geometry and tr...

I don't blame you for sucking at geometry

eager seal Mar 13, 2022, 2:12 PM

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anyways try to implement that code in a command or something and broadcast the outcome to see if the math is correct

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also remember that trigo functions in java use radians

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not degrees

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i'll go code, ping me if u need any help

tawdry creek Mar 13, 2022, 2:15 PM

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eager seal i'll go code, ping me if u need any help

Okay I'll just send you a message if it doesn't work 😁 thanks

#Trigonometry