How do I do ObjectRaycast the right way?

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Xaby

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Posted: 2nd Mar 2017 18:03 Edited at: 2nd Mar 2017 18:54

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Hello everyone.

I wanted to try something like minecraft. I wanted to look at a cube and raycast the cube with ObjectRayCast(0...) from my Head (camera on an object) to faraway.
This works all good. I knew with

If GetObjectRayCastNumHits()>0
HitID = GetObjectRayCastNumHits()-1
hitObjID = GetObjectRayCastHitID(HitID)
EndIf

I will get the right object I am looking at. But I want to draw a transparent cube where the new one can be placed. And there is the problem. I don't want to cast the Object I want to place or other helper-objects and Brush-Visuals for the Objects I want to place or 3D Arrows to show where I can do something.

How can I cast all, but only special objects not or how can I cast groups of objects? Or is there an easy way arround?

Something with the HitID, but I can't figure out, how I cast through the object that is nearest to me, but not the object I want to cast, because that's the object I want to place.

Thanks for help.

I changed the tutorial to ObjectRaycast and GetObjectRayCastX, but in the last example there is only one Object.
I don't know how to do this red ball the easy way.

[youtube]https://www.youtube.com/watch?v=sM4T_sZO6KI[/youtube]

My Code so far

// this example should work in AGK V1 and AGK V2

// use the w and s key or the push up and down on the on screen joystick to move the two spheres back and forth
// the cube will turn red if the raycast - from the green sphere to the red sphere - intersects it

SetAntialiasMode( 1) // 4X-MSAA
SetScreenResolution(1280,720)
SetDisplayAspect( 1.75 ) // ca. 16:9

//SetWindowSize(1280,720,0,1)

SetWindowTitle(":: FL Cubes ::")

//AddVirtualJoystick( 1, 1, 1, 10 )

// create a box (it will automaticall be located at point 0,0,0)

CreateObjectBox(2,1,8,8)
SetObjectColor(2,255,128,128,255)

For i = 5 to 8
	//objID = CreateObjectBox(8*i+8,8*i+8,8*i+8)
	CreateObjectBox(1+i,20,20,20)
	objID=1+i
	SetObjectPosition(objID,0,0,-60+40*i-150)
	SetObjectColor(objID,25,100,255,255)
Next

// create a green sphere and position it
CreateObjectSphere(30,10,12,12)
SetObjectColor(30,255,0,0,255)
SetObjectPosition(30,-50,0,50)

// create a red sphere and position it
CreateObjectSphere(20,10,12,12)
SetObjectColor(20,0,255,0,255)
SetObjectPosition(20,50,0,20)

// create a direction to make the whole scene look better (go on, delete this line and you'll find out why I included it)
//CreatePointLight(1,-1,-1,-1,255,255,255)

//CreateListOfElements()

// position and orientate the camera
SetCameraPosition(1,100,150,-60)
SetCameraLookAt(1,0,0,0,0)

// main loop
hitID=-2
do

// get player input (multiply by -1 so sphere move in direction the joystick is pushed, once again delete it and see what happens)
        joystick_y# = GetJoystickY() * -1

// move the spheres based on input
        MoveObjectLocalZ(20, joystick_y#)
        MoveObjectLocalZ(30, joystick_y#)

// ray cast from the green sphere to the blue sphere
        old_x# = GetObjectX(20)-11
        old_y# = GetObjectY(20)
        old_z# = GetObjectZ(20)

new_x# = GetObjectX(30)+11
        new_y# = GetObjectY(30)
        new_z# = GetObjectZ(30)

lasthitID = hitID
		hitID=-2

//SetObjectVisible(2,0)
        if ObjectRayCast(0,old_x#,old_y#,old_z# ,new_x#,new_y#,new_z#) = 1
			
				
						
		EndIf
		//SetObjectVisible(2,1)
		
			
		
		If GetObjectRayCastNumHits()>0
			Hit = GetObjectRayCastNumHits()-1
		  hitID = GetObjectRayCastHitID(Hit)	
		/*  if hitID =2
			Hit = GetObjectRayCastNumHits()
		    hitID = GetObjectRayCastHitID(Hit)	
		   EndIf  
		  */	
		EndIf	
		
		
		If hitID<>-2
						
                SetObjectColor(hitID,255,255,0,255)
                
          /*
                // get the ray cast intersect point
                intersect_x# = GetObjectRayCastX(Hit)
                intersect_y# = GetObjectRayCastY(Hit)
                intersect_z# = GetObjectRayCastZ(Hit)

// set the position of the blue sphere to the intersect point
                SetObjectPosition(2,intersect_x#,intersect_y#,intersect_z#)

// make the blue sphere visible
                SetObjectVisible(2,1)
		 */ 		     
                
        EndIf
        If lasthitID<>hitID
			    SetObjectVisible(2,0)
                SetObjectColor(lasthitID,25,100,255,255)              
              
                
        Endif
        
        Print (Str(GetObjectRayCastDistance( 0 ),2))
        print(Str(GetObjectRayCastNumHits()))
        Print (Str(hitID))

sync()
loop

+ Code Snippet

// this example should work in AGK V1 and AGK V2

// use the w and s key or the push up and down on the on screen joystick to move the two spheres back and forth
// the cube will turn red if the raycast - from the green sphere to the red sphere - intersects it




SetAntialiasMode( 1) // 4X-MSAA
SetScreenResolution(1280,720)
SetDisplayAspect( 1.75 ) // ca. 16:9

//SetWindowSize(1280,720,0,1)


SetWindowTitle(":: FL Cubes ::")

//AddVirtualJoystick( 1, 1, 1, 10 )

// create a box (it will automaticall be located at point 0,0,0)

CreateObjectBox(2,1,8,8)
SetObjectColor(2,255,128,128,255)


For i = 5 to 8
	//objID = CreateObjectBox(8*i+8,8*i+8,8*i+8)
	CreateObjectBox(1+i,20,20,20)
	objID=1+i
	SetObjectPosition(objID,0,0,-60+40*i-150)
	SetObjectColor(objID,25,100,255,255)
Next	

// create a green sphere and position it
CreateObjectSphere(30,10,12,12)
SetObjectColor(30,255,0,0,255)
SetObjectPosition(30,-50,0,50)

// create a red sphere and position it
CreateObjectSphere(20,10,12,12)
SetObjectColor(20,0,255,0,255)
SetObjectPosition(20,50,0,20)

// create a direction to make the whole scene look better (go on, delete this line and you'll find out why I included it)
//CreatePointLight(1,-1,-1,-1,255,255,255)

//CreateListOfElements()


// position and orientate the camera
SetCameraPosition(1,100,150,-60)
SetCameraLookAt(1,0,0,0,0)

// main loop
hitID=-2
do

 

        // get player input (multiply by -1 so sphere move in direction the joystick is pushed, once again delete it and see what happens)
        joystick_y# = GetJoystickY() * -1

        // move the spheres based on input
        MoveObjectLocalZ(20, joystick_y#)
        MoveObjectLocalZ(30, joystick_y#)

        // ray cast from the green sphere to the blue sphere
        old_x# = GetObjectX(20)-11
        old_y# = GetObjectY(20)
        old_z# = GetObjectZ(20)

        new_x# = GetObjectX(30)+11
        new_y# = GetObjectY(30)
        new_z# = GetObjectZ(30)

		lasthitID = hitID
		hitID=-2

		
		//SetObjectVisible(2,0)
        if ObjectRayCast(0,old_x#,old_y#,old_z# ,new_x#,new_y#,new_z#) = 1
			
				
						
		EndIf
		//SetObjectVisible(2,1)
		
			
		
		If GetObjectRayCastNumHits()>0
			Hit = GetObjectRayCastNumHits()-1
		  hitID = GetObjectRayCastHitID(Hit)	
		/*  if hitID =2
			Hit = GetObjectRayCastNumHits()
		    hitID = GetObjectRayCastHitID(Hit)	
		   EndIf  
		  */	
		EndIf	
		
		
		If hitID<>-2
						
                SetObjectColor(hitID,255,255,0,255)
                
          /*
                // get the ray cast intersect point
                intersect_x# = GetObjectRayCastX(Hit)
                intersect_y# = GetObjectRayCastY(Hit)
                intersect_z# = GetObjectRayCastZ(Hit)

                // set the position of the blue sphere to the intersect point
                SetObjectPosition(2,intersect_x#,intersect_y#,intersect_z#)

                // make the blue sphere visible
                SetObjectVisible(2,1)
		 */ 		     
                
        EndIf
        If lasthitID<>hitID
			    SetObjectVisible(2,0)
                SetObjectColor(lasthitID,25,100,255,255)              
              
                
        Endif
        
        Print (Str(GetObjectRayCastDistance( 0 ),2))
        print(Str(GetObjectRayCastNumHits()))
        Print (Str(hitID))
        

        sync()
loop

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Markus

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Joined: 10th Apr 2004

Location: Germany

Posted: 2nd Mar 2017 18:15

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there are commands to convert screen pos. into 3d direction.

AGK (Steam) V2017.01.09 : Windows 10 Pro 64 Bit : AMD (16.12.1) Radeon R7 265 : Mac mini OS Sierra (10.12.2)

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Xaby

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Location: Berlin

Posted: 2nd Mar 2017 18:58

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@Markus

sounds great, but how can I use this information with the problem, that I want to cast not every object in the ray? My program hast to work also in 3rd person and other camera angles.

Can you post a little code snippet, do clarify your thought?

Thanks for help.

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29 games

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Posted: 2nd Mar 2017 22:48

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There are a couple of ways to do this. Below is an example of what I think is simplest.

SetAntialiasMode( 1) // 4X-MSAA
SetScreenResolution(1280,720)
SetDisplayAspect( 1.75 ) // ca. 16:9

//SetWindowSize(1280,720,0,1)

SetWindowTitle(":: FL Cubes ::")

//AddVirtualJoystick( 1, 1, 1, 10 )

// create a box (it will automaticall be located at point 0,0,0)

// create a type and an array for the box variables
type _box_type
	obj as integer
	state as integer
endtype
dim box[25] as _box_type

// create some boxes and put their ID's into an array
num_boxes = 0
For z = 0 to 4
	for x = 0 to 4

inc num_boxes

box[num_boxes].obj = CreateObjectBox(20,20,20)
		SetObjectPosition(box[num_boxes].obj,30*(x-2),0,30*(z-2))

// randomly set the boxes state for purposes of collision
		box[num_boxes].state = random(0,1)

next x
Next z

// create a green sphere and position it
CreateObjectSphere(30,10,12,12)
SetObjectColor(30,255,0,0,255)
SetObjectPosition(30,-100,0,0)

// create a red sphere and position it
CreateObjectSphere(20,10,12,12)
SetObjectColor(20,0,255,0,255)
SetObjectPosition(20,100,0,0)

// create a direction to make the whole scene look better (go on, delete this line and you'll find out why I included it)
SetSunActive(1)
SetSunDirection(1,-1,1)

//CreateListOfElements()

// position and orientate the camera
SetCameraPosition(1,100,170,-100)
SetCameraLookAt(1,0,0,0,0)

// main loop
hitID=0
do

// get player input (multiply by -1 so sphere move in direction the joystick is pushed, once again delete it and see what happens)
        joystick_y# = GetJoystickY() * -1

// move the spheres based on input
        MoveObjectLocalZ(20, joystick_y#)
        MoveObjectLocalZ(30, joystick_y#)

// ray cast from the green sphere to the blue sphere
        old_x# = GetObjectX(20)-11
        old_y# = GetObjectY(20)
        old_z# = GetObjectZ(20)

new_x# = GetObjectX(30)+11
        new_y# = GetObjectY(30)
        new_z# = GetObjectZ(30)

lasthitID = hitID

for i = 1 to 25
			select box[i].state

// turn collision off - make it transparent
				case 0
					SetObjectCollisionMode(box[i].obj,0)
					SetObjectColor(box[i].obj,0,255,255,150)
					SetObjectTransparency(box[i].obj,1)
				endcase

// turn collision on - make it opaque
				case 1
					SetObjectCollisionMode(box[i].obj,1)
					SetObjectColor(box[i].obj,25,100,255,150)
					SetObjectTransparency(box[i].obj,0)
				endcase

endselect
		next i

// ray cast all the boxes and saved it's id
		// it will only do a ray cast with the boxes that have their collision turned on
		// and will return the id of the first object to be hit
        hitID = ObjectRayCast(0,old_x#,old_y#,old_z# ,new_x#,new_y#,new_z#)

// if the hitID is greater than zero then a box then highlight the box that has been hit
        If hitID > 0
                SetObjectColor(hitID,255,255,0,255)
        EndIf

Print (Str(GetObjectRayCastDistance( 0 ),2))
        print(Str(GetObjectRayCastNumHits()))
        Print (Str(hitID))

sync()
loop

+ Code Snippet

SetAntialiasMode( 1) // 4X-MSAA
SetScreenResolution(1280,720)
SetDisplayAspect( 1.75 ) // ca. 16:9

//SetWindowSize(1280,720,0,1)


SetWindowTitle(":: FL Cubes ::")

//AddVirtualJoystick( 1, 1, 1, 10 )

// create a box (it will automaticall be located at point 0,0,0)

// create a type and an array for the box variables
type _box_type
	obj as integer
	state as integer
endtype
dim box[25] as _box_type

// create some boxes and put their ID's into an array
num_boxes = 0
For z = 0 to 4
	for x = 0 to 4

		inc num_boxes

		box[num_boxes].obj = CreateObjectBox(20,20,20)
		SetObjectPosition(box[num_boxes].obj,30*(x-2),0,30*(z-2))

		// randomly set the boxes state for purposes of collision
		box[num_boxes].state = random(0,1)

	next x
Next z



// create a green sphere and position it
CreateObjectSphere(30,10,12,12)
SetObjectColor(30,255,0,0,255)
SetObjectPosition(30,-100,0,0)

// create a red sphere and position it
CreateObjectSphere(20,10,12,12)
SetObjectColor(20,0,255,0,255)
SetObjectPosition(20,100,0,0)

// create a direction to make the whole scene look better (go on, delete this line and you'll find out why I included it)
SetSunActive(1)
SetSunDirection(1,-1,1)

//CreateListOfElements()


// position and orientate the camera
SetCameraPosition(1,100,170,-100)
SetCameraLookAt(1,0,0,0,0)

// main loop
hitID=0
do



        // get player input (multiply by -1 so sphere move in direction the joystick is pushed, once again delete it and see what happens)
        joystick_y# = GetJoystickY() * -1

        // move the spheres based on input
        MoveObjectLocalZ(20, joystick_y#)
        MoveObjectLocalZ(30, joystick_y#)

        // ray cast from the green sphere to the blue sphere
        old_x# = GetObjectX(20)-11
        old_y# = GetObjectY(20)
        old_z# = GetObjectZ(20)

        new_x# = GetObjectX(30)+11
        new_y# = GetObjectY(30)
        new_z# = GetObjectZ(30)

        lasthitID = hitID

		for i = 1 to 25
			select box[i].state

				// turn collision off - make it transparent
				case 0
					SetObjectCollisionMode(box[i].obj,0)
					SetObjectColor(box[i].obj,0,255,255,150)
					SetObjectTransparency(box[i].obj,1)
				endcase

				// turn collision on - make it opaque
				case 1
					SetObjectCollisionMode(box[i].obj,1)
					SetObjectColor(box[i].obj,25,100,255,150)
					SetObjectTransparency(box[i].obj,0)
				endcase

			endselect
		next i

		// ray cast all the boxes and saved it's id
		// it will only do a ray cast with the boxes that have their collision turned on
		// and will return the id of the first object to be hit
        hitID = ObjectRayCast(0,old_x#,old_y#,old_z# ,new_x#,new_y#,new_z#)

		// if the hitID is greater than zero then a box then highlight the box that has been hit
        If hitID > 0
                SetObjectColor(hitID,255,255,0,255)
        EndIf

        Print (Str(GetObjectRayCastDistance( 0 ),2))
        print(Str(GetObjectRayCastNumHits()))
        Print (Str(hitID))


        sync()
loop

In this example I've used a flag that simply gives a state for the box which controls whether the collision for the box is turn on or off. In your case you will want to control the box's state depending of whether the box has been positioned or not. You might actually want more than two states. You might want:

state = 0 -- box has not been placed and is invisible and there should be no interaction with this box.
state = 1 -- box is being placed, is transparent but doesn't block line of sight
state = 2 -- box has been placed and now blocks line of sight.

If you want to do groups then you could have a group variable in the _box_type - or whatever other objects you might have - and then when you want to do collision with a particular group simply turn off the collision for all the other groups. Another way to do groups is to only loop through the objects that you are interested in and check collision with each individual object in that group but this won't necessarily give you the id of the nearest object.

I also did an object picker which you also might find useful: https://www.appgamekit.com/documentation/Reference/3D/Get3DVectorXFromScreen.htm

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Xaby

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Posted: 3rd Mar 2017 07:56 Edited at: 3rd Mar 2017 08:08

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@Markus, @29 Games,

thanks for your fast answer.

@29 games, your example is great, maybe this could be added to the examples too

That was my missing command

SetObjectCollisionMode( objID, mode )

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Markus

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Posted: 3rd Mar 2017 09:12

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the commands in meant was
Get3DVectorXFromScreen ( x, y )
Get3DVectorYFromScreen ( x, y )
Get3DVectorZFromScreen ( x, y )
GetScreenXFrom3D ( x, y, z )
GetScreenYFrom3D ( x, y, z )

RayCast give you a list, you can also igrone obj ids from the result.

AGK (Steam) V2017.01.09 : Windows 10 Pro 64 Bit : AMD (16.12.1) Radeon R7 265 : Mac mini OS Sierra (10.12.2)

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Xaby

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Posted: 5th Mar 2017 07:34

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@Markus, I understand, that you meat these commands, but to use them, I have to know, where the Ray hits the object. The example from 29 Games is realy that, what helped me out.

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