I am trying to create a basic spawn sequence- the block must be created, moveDownLeft, and then removeLeft. moveDownLeft and removeLeft work fine on their own when the block is added using self.addChild(block1) previously, however I need to have self.addchild within the sequence.
The only way that I can see to do this is use runBlock, and I looked at this question when I got an error using that: Swift: SKAction.runBlock -> Missing argument for parameter 'completion' in call BUT WHY?
So now I am left with this:
block1.runAction(SKAction.sequence([SKAction.runBlock({ self.addChild(self.block1) }), moveDownLeft, removeLeft]))
And nothing in the sequence works because the block is not created in the first place. Why is this happening?
Your code fragment is too short but it looks like a typical chicken and egg problem.
node can only run actions once it has been added as child and thus becomes part of the scene graph
your node is supposed to run an action that will eventually add itself to the scene graph but it's not in the scene graph yet so it won't run that action
Add the node as child first, then run the action. If you need the node to be inactive for some time, simply set it's visible property to NO for the duration. You kay also ned to change other properties, ie postpone creation of the physics body.
Related
Hey im trying to get an object which is referenced in another script (dictionary).
But when i try to get the object in the start method it seems like the dictionary isnt populated jet.
Error: NullReferenceException: Object reference not set to an instance of an object
If I run this line of code in the update method it works completely fine.
Is there an easy way to let this line run after the dictionary is populated?
Grid Manager Script
Camera Movement Script
Both your code snippets run in Start.
There is no way to predict in which order these two Start messages will be invoked (at least not from the user perspective).
To solve this kind of race conditions (see Order of execution for event functions).
The Awake function is called on all objects in the Scene before any object's Start function is called.
my general thumb-rule is:
Use Awake
to initialize the component itself where it doesn't depend on values
from other components.
E.g. initializing your fields, filling your collections, using GetComponent etc to initialize references (but stop there)
Use Start to then initialize things where you do depend on other components being already initialized.
Like in your case access the collections of the other component
This usually covers most of the cases.
In your case simply converting GridManager.Start to GridManager.Awake should already solve the issue.
Where this is not enough you either can start and tweak the Script Execution Order and basically enforce a certain order in which the event methods get invoked or implement a more complex event based initialization system
Populate the dictionary in Awake() method instead of Start(), then it would be ready by the time you need it in Start() of another script.
For a project I'm trying to select the right output if a parameter of the created agent is true. The agent is created in the main but goes into a different agent for the selection of the output. If I use a select in the main and use the statement for the parameter as condition it works fine. Whenever it enters the agent and I use the same statement it gives an error (Description: product1 cannot be resolved or is not a field. Location: testCase5/Transport/selectOutput - SelectOutput).
I tried using different conditions like main.agent.product1 . Can't seem to solve the issue. I know that it has to do something with declaration probably but I'm clueless at the moment.
//for the condition that works if I put the selectOutput in the main
agent.product1
//for the condition in the agent I tried the same but didn't work. also tried
main.agent.product1 // Gives the same error but for (Description: agentcannot be resolved or is not a field.)
(Main)agent.product1
//And a few more
In AnyLogic each block of a project flow (regardless if from the process modeling library, the pedestrian library or another) has the type of Agent that is flowing through it defined in its properties. You can find this setting as Agent type in the block's properties under Advanced.
If you fail to set this correctly (meaning this setting equals the type of Agents you let flow through it), it will still flow through, BUT: you cannot access the specific properties of the Agent type.
That said, usually you do not even have to think about, because AnyLogic has an automatism there: The first block of your process flow, typically a Source-block or a Enter-block is the only block where you have to make the correct setting, all attached blocks get it then automatically!
However this does not work when:
You have separate flows (eg. you leave one flow through an Exit-block and enter another by an Enter). You'll manually have to put the correct setting also for the first block of the second process flow.
Your process flow is continued inside of another Agent/Custom Block, as in your example. AnyLogic doesnt realize the process flow inside your custom block is logically connected to the outside process flow in main. You have to specifiy manually again the Agent type flowing through in the first block of your process inside your Custom Block.
I am having trouble with my Unreal Engine 4 project. I'm very new to this and i don't really understand what's going on. I have made ladder functionality so the character can climb up the ladder and stand on the Static Mesh that is on top. But when i want to go down the ladder i want to trigger the "Allow Down" function on Actor "BP_Ladder" but the cast is failing everytime. what is causing the casts to fail?
I've looked around and other people with cast failed problems have mostly had the names wrong but my ladder is called "BP_Ladder" and that is what i'm casting to so that leaves me really confused.
My BP_Dude blueprint (this is being called every tick)
My BP_Ladder blueprint (this is what i'm trying to trigger)
The goal for this function is that the collision of the static mesh will turn off and then allow me to move down the ladder like normal.
I'd really appreciate your help with this, its my first couple of days using unreal engine and the Epic Games tutorials i followed didn't show all of the blueprints so everyone was left helpless with half broken blueprints.
Understanding Casts
In its simplest form, if your Actor can be cast to BP_Ladder, then it will return the casted object on the output pin.
Just to ensure you know how a cast works, I have to point out that you can't cast a given type to some unrelated arbitrary type; it has to be "castable" to the cast destination. So if you think that the Actor object returned by your overlap is genuinely a BP_Ladder, or a blueprint class that derives from BP_Ladder, then you should be OK. But that has to be the case; otherwise it will fail every time.
https://docs.unrealengine.com/en-us/Engine/Blueprints/UserGuide/CastNodes
Sorry if I'm being patronising, but if a cast isn't working 9/10 it hasn't been used correctly.
Debugging
OK that out of the way, if you think you are genuinely casting to the correct type and it's still failing, then you'll need to debug your blueprint with the objective of finding what type is being given to the cast node which results in the failure.
Select the cast object in your blueprint.
Press F9 to create a breakpoint; a red circle should appear on the top left of your cast box
Run your game in PIE mode (Combo next to play, New Editor Window (PIE))
Put the game in a scenario where your cast will fire (I presume touch the ladder)
The breakpoint should trigger; your game window will go grey and you'll get a large red arrow pointing down towards your cast box where you placed the breakpoint
Hover over the Object pin on the input side of the cast box. It should show a alt-text containing details of the variable.
Inside the alt-text box, look for Current value; this should show you the current object type that you are about to cast. You need to ensure that this value is what you expect.
https://docs.unrealengine.com/en-US/Engine/Blueprints/UserGuide/Debugging
Example
I've taken a screenshot of a working game; in this you will see:
a Breakpoint (the red circle) is shown on the function node (the box)
the Execution node (red arrow) is Create Rolling Stock
the Current value of the variable is DepotComponent...Depot
Final thoughts
There's a couple of gotchas when using blueprints; one of them in this case could be that you can have two classes with the same name (although they might have different internal "script names" - effectively a fully qualified path). When you debugging an object variable, make sure you match the entire path to the location of your asset in your content folder; this will ensure that you are indeed attempting to cast to the object you think you really are.
Another classic gotcha is "hot reloads". Sometimes the editor needs to reload a module after an on-the-fly build but a class conflict occurs internally; this results in the new version of the class getting a different name (prefixed with HOTRELOADED). Watch out for this; it can cause you to be dealing with two distinct types when casting and you don't even realise. A real sanity-sapper. If in doubt, close and re-open the editor; it fixes it every time.
On Begin Overlap is only triggered when you START an overlap, so if you have some logic that sets your "can climb" to false you will need to move outside of the collider and back into it again for another Begin Overlap event.
In my scene I have 2 camera(split screen). it's possible change the trasparency of a layer only for one camera? for examples the "layer1" have alphatrasparency = 0.5 for right camera while left camera show "layer1" without trasparency.
Ostensibly no
There's a way to do it, though. It's a bit of a hack though, as it doesn't depend on physics layers, but rather the presence of a custom monobehavior script. Here's what I remember about this off the top of my head (I can dig up an implementation later, if needed).
Step 1: you will need a MonoBehaviour script attached to every game object you want to have rendered differently. This script is absolutely essential.
Step 2: this script will contain one function (you can use an existing behaviour script if all the objects already have one in common and you can just add this function to that script). Call it whatever you want, but something like AboutToBeRendered(Camera cam)
Step 3: create another script and attach it to both cameras. This script will also have one function in it: OnPreRender()
Step 4: In this OnPreRender method you will need to do:
find all game objects from Step 1
get their component with the AboutToBeRendered method
invoke that method, passing the camera as the paramter
Step 5: Writing the AboutToBeRendered method.
determinie which of the two cameras was passed to the method
set the material's color to be transparent or not, as needed
OnPreRender() is only called on scripts with a camera component on the same GameObject, indicating that this camera is about to render the scene. But what we actually want is for the object about to be rendered to know that it's about to be rendered and by which camera. Which is why we need the script in step 1.
I suppose you could skip step 1 and only look at every object in the scene and look at its physics layer, but that's going to be more expensive to figure out than "get me all instances of this component." You could do it based on Tag instead, as FindObjectsWithTag is generally considered to be pretty fast, but if you're already using the tag for something else, you're out of luck, and there's no comparable method for getting objects in a given physics layer.
However, you'd have to tweak the material's alpha value in the camera script rather than letting the object itself decide what value it should be.
In either case, the object's material would need to support transparency. When I did this I was preventing the object from being rendered entirely, so I just disabled its MeshRenderer component.
I have a gtk.Fixed. I move components inside it around using:
myFixed.move( myEventBox, new_x, new_y )
What event do I listen for to know when myEventBox has been rendered at its new position?
Do I connect to the fixed or the eventbox?
MORE INFO:
I need this information so I know when it is safe to queue a video under the eventbox... if I do it too soon (e.g. right after calling myFixed.move) I can see the glitch. Currently getting around this with a gobject.idle_add.
To be honest, I am not aware of any such event. The object should move immediately and redraw the screen, but I don't think any signal is emitted when that happens.
The PyGTK documentation is very comprehensive, and it will list all of the functions and events of every object in the library. In searching (through both the gtk.Container (for fixed) and gtk.Widget (for fixed and eventbox) signal lists, I can't find any such event. The closest thing is an "add" signal in gtk.Container, but I don't think that's what you're looking for.
If the object is not moving, please post your code, because there is probably a subtle error.
If the object is moving just fine and you just want the event/signal, you may have to simulate it yourself. Write the function you want to be called as soon as the object is moved in a function (def) inside "__ init __", and then call that function in code in the line right after "myFixed.move".