ObjectRayCast question? - GameCreators Forum

Author

Message

Golelorn

7

Years of Service

User Offline

Joined: 20th Nov 2016

Location:

Posted: 19th Jun 2019 21:17

Link

I thought I had this figured out, but I keep getting inconsistent results. Or perhaps, I have forgotten what I learned, since I haven't messed with this command in awhile.

If I do ObjectRayCast(1,x,y,z,nx,ny,nz) Shouldn't it return a 0 if there is another object between the ray? Or is this only testing to see if the one object is in the ray path?

Conversely, if I send out a ray of ObjectRayCast(0,x,y,z,nx,ny,nz) should it not return the first object hit? Instead I get the object hit at the end of the ray, and the object in-between is only hit if I put that object ID in(so I know its not a case of me inadvertently turning off collision mode).

I could have sworn I have mentioned this before, but the documentation is wrong. ObjectRayCast() only returns a 1 if you put in the ObjectID.

Doc page

Quote: "will return the number of the object hitt first, or 0 for no collision"

Would be nice to get that fixed.

Back to top

Profile PM

fubarpk

Retired Moderator

19

Years of Service

User Offline

Joined: 11th Jan 2005

Playing: AGK is my friend

Posted: 20th Jun 2019 02:05

Link

The easiest way to raycast I find is to check for object collision with the below function

//EDITED as I noticed I was using x when y and z calculations were needed 
function checkCollision(objID as integer)

local width# as float
local height# as float
local depth# as float
local x# as float
local y# as float
local z# as float
local start_x# as float
local start_y# as float
local start_z# as float
local end_x# as float
local end_y# as float
local end_z# as float 
local object_Hit as integer

//this checks for colliion between an object with any other object and returns its id
width#=(GetObjectMeshSizeMaxX(objID,1)-GetObjectMeshSizeMinX(objID,1))/2 
height#=(GetObjectMeshSizeMaxY(objID,1)-GetObjectMeshSizeMinY(objID,1))/2 
depth#=(GetObjectMeshSizeMaxZ(objID,1)-GetObjectMeshSizeMinZ(objID,1))/2 
 
x#=getObjectWorldX(objID)
y#=GetObjectWorldY(objID)
z#=getObjectWorldZ(objID)

// calculate the start of the ray cast
start_x# = x#-width#
start_y# = y#+height#
start_z# = z#-depth#

// calculate the end of the ray cast
end_x# = x#+width#   
end_y# = y#-height#
end_z# = z#+depth#
 
// determine which object has been hit
object_Hit = ObjectRayCast(0,start_x#,start_y#,start_z#,end_x#,end_y#,end_z#) :rem returns the object ID
rem if you change this to object_Hit = ObjectRayCast(obj2ID,start_x#,start_y#,start_z#,end_x#,end_y#,end_z#) it will return 1 or 0
endfunction object_Hit

+ Code Snippet


//EDITED as I noticed I was using x when y and z calculations were needed 
function checkCollision(objID as integer)

local width# as float
local height# as float
local depth# as float
local x# as float
local y# as float
local z# as float
local start_x# as float
local start_y# as float
local start_z# as float
local end_x# as float
local end_y# as float
local end_z# as float 
local object_Hit as integer	

//this checks for colliion between an object with any other object and returns its id
width#=(GetObjectMeshSizeMaxX(objID,1)-GetObjectMeshSizeMinX(objID,1))/2 
height#=(GetObjectMeshSizeMaxY(objID,1)-GetObjectMeshSizeMinY(objID,1))/2 
depth#=(GetObjectMeshSizeMaxZ(objID,1)-GetObjectMeshSizeMinZ(objID,1))/2 
 
x#=getObjectWorldX(objID)
y#=GetObjectWorldY(objID)
z#=getObjectWorldZ(objID)


// calculate the start of the ray cast
start_x# = x#-width#
start_y# = y#+height#
start_z# = z#-depth# 

// calculate the end of the ray cast
end_x# = x#+width#   
end_y# = y#-height#
end_z# = z#+depth#
 
// determine which object has been hit
object_Hit = ObjectRayCast(0,start_x#,start_y#,start_z#,end_x#,end_y#,end_z#) :rem returns the object ID
rem if you change this to object_Hit = ObjectRayCast(obj2ID,start_x#,start_y#,start_z#,end_x#,end_y#,end_z#) it will return 1 or 0
endfunction object_Hit

fubarpk
fubarpk on Itch...………...https://fubarpk.itch.io/
fubarpk on googleplay..https://play.google.com/store/apps/developer?id=fubarpk

Back to top

Profile PM Email Website

Ortu

DBPro Master

16

Years of Service

User Offline

Joined: 21st Nov 2007

Location: Austin, TX

Posted: 20th Jun 2019 23:33 Edited at: 20th Jun 2019 23:34

Link

If it isn't returning the first object hit, then yeah that's probably a bug.

I did notice this in the docs though as a work around:

+ Code Snippet

     n=GetObjectRayCastNumHits()
     print("GetObjectRayCastNumHits "+str(n))
     for i=0 to n-1
      obj = GetObjectRayCastHitID(i)
      print("Obj " +str(obj))
      print(GetObjectRayCastY(i))
     next

Looks like if multiple objects are hit, it keeps a list of all of them that you can scan through.

If it's actually returning the last object hit instead of the first, then possibly you just want the hit at the other end of the list...

http://games.joshkirklin.com/sulium

A single player RPG featuring a branching, player driven storyline of meaningful choices and multiple endings alongside challenging active combat and intelligent AI.

Back to top

Profile PM Email Website

Golelorn

7

Years of Service

User Offline

Joined: 20th Nov 2016

Location:

Posted: 21st Jun 2019 15:29

Link

Thanks, Ortu. I will see if that is the case.

Back to top

Profile PM

Bryan Ruffin

5

Years of Service

User Offline

Joined: 16th Apr 2019

Location:

Posted: 27th Jun 2019 07:20

Link

I high appreciate this post. It’s hard to find the good from the bad sometimes, but I think you’ve nailed it! would you mind updating your blog with more information?
geometry dash

Back to top

Profile PM

Sorry your browser is not supported!

Newcomers AppGameKit Corner / ObjectRayCast question?