how make "Moving Platforms" Face direction of motion

[Russell]

Hello again...

I'm working on a last map for showing CREDITS about my game. I will use a camera attached to a moving platform, using platform.lua and platformwaypoint.lua for the points of the trip. And the idea is the camera move across the map where the credits are exposed...

I have designed the trip, and the platform with the camera attached on it moves ok.

But I have an important question about a problem whose the solution I have not been able to find in the forums, neiher looking on Google...

Is there a way (or command) with which I can make the moving platform turn in the direction that is moving?

Like something moving always "Face of motion".

At this moment, when the platform turn left or right on the next waypoints, the platform still looking in the same direction. And the camera attached on it too. I want the platform turn in face of motion. ¿Is possible?

[Thirsty Panther]

I think point is what you are after.

https://www.leadwerks.com/learn?page=API-Reference_Object_Math_Transform_Point

[Russell]

13 hours ago, Thirsty Panther said:

I think point is what you are after.

https://www.leadwerks.com/learn?page=API-Reference_Object_Math_Transform_Point

I tried to understand this entity "Point". I have done the example with the blue box... But i don't know how works or how apply this entity to my moving platform.

I'm reading other post in the forum about how use this "point", but i don't understand how use it anyway... ????

[Russell]

I'm testing this with this example platform (The red face should always go to the front, but it doesn't?

I don't know how solve my case of how platform turn face direction of motion and i don't understand "Point" entity sintax to help me with this...

In other engines, like valve's Hammer, we have this option:

In Leadwerks is anything like that  or a code for Moving Platforms?

[Russell]

I think this is the part of the platform code i need to put the POINT code entity (last part of this code between comments):

function Script:SetTarget(newTarget)
	self.currentPosition = self.entity:GetPosition()
	self.originPosition = self.entity:GetPosition()
	self.targetPosition = newTarget:GetPosition()
	self.distance = self.originPosition:DistanceToPoint(self.targetPosition)
	self.target = newTarget

	local pos = self.entity:GetPosition(true)
	local targetpos = self.target:GetPosition(true)
	local pin = pos - targetpos
	self.distance = pin:Length()
	pin = pin:Normalize()

	if self.joint then
		self.joint:DisableMotor()
		self.joint:Release()
	end
	self.joint=Joint:Slider(targetpos.x,targetpos.y,targetpos.z,pin.x,pin.y,pin.z,self.entity,nil)
	self.joint:EnableMotor()
	self.joint:SetMotorSpeed(self.speed)
	self.joint:SetAngle(-self.distance)
  	--Here i think is needed Point code to turn my platform face direction of motion:
	self.Transform:Point(targetpos.x,targetpos.y,targetpos.z,nil,model)
  	--Don't know what parameters i need to platform FACE up direction to the pivot waypoint...
end

Thanks in advance for your help!!

[Marcousik]

Here I don't know how point() function is doing with joint functions...

But I would calculate a simple cosinus/sinus/tan math functions to determine the angle you need for your entity to face the waypoint.

Then use a joint kinematic on the entity instead of slider: https://www.leadwerks.com/learn?page=API-Reference_Object_Joint_Kinematic

move with joint:SetTargetPosition() https://www.leadwerks.com/learn?page=API-Reference_Object_Joint_SetTargetPosition

So then just apply the angle with joint:SetTargetRotation() https://www.leadwerks.com/learn?page=API-Reference_Object_Joint_SetTargetRotation

[reepblue]

When importing your models, the front should always be Z positive. Then you can use The point function of the entity to point to it's target like:

self.enitity:Point(self.target,2,1,0)

Only concern I have is that the joint locks the rotation of the entity so you might need to disable the mass of the train before you can manipulate the rotation. Then re-apply the mass.

Never did this, but that would be my first attempt.

 

[Russell]

Thanks for your answers!!

I will study all of them, for make my platform turn face of motion. I'm little confuse about how use of all those entities in learn page wiki, but i will manage to success this question about the platform.

I don't know if I'll get it. But if I succeeded, I will post it here my solution.

Many thanks team!! I am very proud and satisfied of the people in this forum. ☺️☺️☺️☺️

[Marcousik]

The kinematic joint functions are looking first more complicated as they are but it runs ok. Just create the joint in the center  - entity:GetPosition() - of the entity you want to move. And the joint:SetTargetPosition + joint:SetTargetRotation are very intuitive. 

Use a mass of about 3 or 5 not more or it won't move.

Feel free to ask if problems 

About what reepblue said, I suppose that the slider joint will force the rotation  as soon as the mass is restored. (but not tested) 

What you could do is to move a pivot with mass along the slider joint and put your box as child and use point() on the child