[1.7.10]How would I get the delta x,y, and z from two entites

[starwarsmace]

Hey guys. How would I get the motion x, y, and z from two entities. What I mean by that is if I have entity A and entity B how would I know what the motion x,y,z would be to get from Entity A to Entity B. (I am making a particle) I know some math as to converting to radians but how would I apply that to this?

[Ernio]

This is 100% math, but before I write something dumb - what is "motion" is this case? You want to compute starting (in A) speed to make entity get from A to B wheras in B the speed will get to 0?

[starwarsmace]

This is 100% math, but before I write something dumb - what is "motion" is this case? You want to compute starting (in A) speed to make entity get from A to B wheras in B the speed will get to 0?

Motion is the speed the particle is moving at.

 

What do you mean by your second question?

[Ernio]

You know, simple physics - there is speed, acceleration, time. If you would set motion x/y/z to exacly value "to ge from A to B" the particle would travel there in time=1[j] wheras [j] in MC is one tick.

 

So computing this way is simply retarded, hence my question and statement "before I write something dumb".

 

You either want a:

- formula for speed of particle in time with acceleration.

- forumla for speed of particle in time, without acceleration

- formula for starting force that should be used on particle for it to travel from A to B (which in the end is actually 1st formula mentioned).

[starwarsmace]

Well....

 

I dont need exact values...

 

motionX *= 0.98000001907348633D;
motionY *= 0.98000001907348633D;
motionZ *= 0.98000001907348633D;

MC has something like that where they multiple the motion.

I need to know how to get the direction in which the particle should travel, and how to set that direction

[Ernio]

One class: EntityLookHelper.

 

Example of code (vanilla):

this.theGolem.getLookHelper().setLookPositionWithEntity(this.theVillager, 30.0F, 30.0F);

 

EDIT:

Check out what happens there (self explainatory), it will take some time, but you should get it.

Then you will need to use same mechanics to make your EntityFX have motion set in given direction. For that you might wanna look at EntityThrowable (arrows).

 

[starwarsmace]

One class: EntityLookHelper.

 

Example of code (vanilla):

this.theGolem.getLookHelper().setLookPositionWithEntity(this.theVillager, 30.0F, 30.0F);

 

EDIT:

Check out what happens there (self explainatory), it will take some time, but you should get it.

Then you will need to use same mechanics to make your EntityFX have motion set in given direction. For that you might wanna look at EntityThrowable (arrows).

 

You bet I'll figure it out!

Anyway thanks for the help.

 

[starwarsmace]

Arrgggg the look helper code is driving me crazy! Ill look more though...

[Draco18s]

motionX *= 0.98000001907348633D;
motionY *= 0.98000001907348633D;
motionZ *= 0.98000001907348633D;

MC has something like that where they multiple the motion.

I need to know how to get the direction in which the particle should travel, and how to set that direction

 

Friction!  Air resistance!

[starwarsmace]

One class: EntityLookHelper.

 

Example of code (vanilla):

this.theGolem.getLookHelper().setLookPositionWithEntity(this.theVillager, 30.0F, 30.0F);

 

EDIT:

Check out what happens there (self explainatory), it will take some time, but you should get it.

Then you will need to use same mechanics to make your EntityFX have motion set in given direction. For that you might wanna look at EntityThrowable (arrows).

 

Im really not getting it...

[starwarsmace]

Would it be better to calculate a vector between the two entities?

[TheGreyGhost]

Hi

 

You are on the right track with vector calculation

 

If you just want the motion to be in a straight line, then it's pretty simple-

 

1) calculate the motion vector = PositionOfB - PositionOfA

2) normalise the vector to convert it to length 1 regardless of the distance between B and A

3) motionX = vectorX * speed

    motionY = vectorY * speed

    motionZ = vectorZ * speed

 

The *0.98 stuff is to slow the projectile down once you have fired it, air resistance as Draco said.  It has no effect on the direction.  Gravity is a different story, that will make your motion curve downwards, but I guess you aren't worried about that?

 

-TGG