I currently have two nodes in use, one of which is a boat (polygon) and the other a straight vertical rectangle. The boat needs to be a polygon so that it can be hit via projectiles, however this causes me problems when it collides with the vertical rectangle due to the many sides it's coming into contact with. Hence a piece of code I want ran only once is instead ran multiple times.
Is there anyway to make the collision detection only function for the first contact so that it doesn't repeatedly call?
I'm aware of setting the categoryBitMask to 0 however doing so renders the boat unable to be hit by anything else- something I don't want. Additionally I considered using a boolean variable to only run the code once whilst the boat is passing through, however as previously mentioned, due to the different sides, the code think it's passed through when in fact it's just hitting another side of the boat.
I don't have much code to show here other than setting physics bodies so I don't think it's necessary, but inside didBeginContact() I'm using a categoryBitMask comparison to check for collisions.
I may have not explained this very well, in which case I apologize, my English is not the best!
If anyone can help, it'd be much appreciated, thanks.
You can combine the individual physics bodies of your ship into a single body with
+ (SKPhysicsBody *)bodyWithBodies:(NSArray *)bodies
and then test for contacts with the composite body instead of the individual components.
If you are subclassing your node then simply create a BOOL property for it.
BOOL alreadyHit;
If you are not subclassing, use the SKNode's userData dictionary and create an entry for the same.
Related
I'm working on a procedural terrain generator using Geometry Nodes and I want to include the option of having buildings or other objects placed inside a collection that the terrain uses as a reference for where not to put grass, pebbles and rocks. The issue I have is that I've been only able to do it with the faces of the objects in the collection, and when they are big enough, that causes the points to be distributed inside the object. Here's a capture:
I've scoured the internet for help, but since the change in the geometry nodes on 3.0, most of the answers I can find use the old system and I can't find a way to adapt it, so I'm asking for help here, because I ran out of ideas. Here's the current set up I have to make the selection to know where not to put points for the grass:
I did try using the Mesh Boolean approach, but it is too resource heavy. For the buildings is not a problem, but when I use it for avoiding grass from spawning inside the big rocks, it makes the entire geometry nodes really heave resources wise.
Any Help is appreciated, I've been fighting this "bug" for three days now and it's driving me crazy. Thanks!
After many searches, I've managed to find a solution that works! It is using the method explained in this tutorial: https://www.youtube.com/watch?v=tvb2aCeTANM
Basically, you create a raycast on top of the scene and use a Boolean Math node to detect if it's hitting or not. In my case, for deleting the Geometry in the mesh where the points are distributed, I used a "Or" operation. You can see the node setup here: New Node Setup
Hope this helps anyone else having the same problem :). Of course if anyone can think of a better solution, feel free to add it!
Just use Raycast node with position node to evaluate a dot product
and then add map range with clamp checkbox
I have been working on a simple game in Unreal Engine 4. I am trying to make it so when a player is hit by a cube they take damage. However, I am stuck on creating a condition. I have previously used:
to set up a condition where a player only takes damage if they are touched by the cube (In my cube pawn blueprints).
This doesn't work however - when trying to set-up my health bar:
This shows that I am now using entirely new variables to attempt to get a successful updating bar.
Without setting it up so when a cube hits the player, the player takes damage, the player will take damage from simply jumping at walking into other surfaces.
I have created a function that successfully updates my current health and max health so I don't need to show, or need help with the maths or updating the widget. Is there a way for me to use the branch to create an if statement that checks the contact is form a cube?
I am quite new to blueprints and have mostly developed through the use of tutorials. If you need clarity on my question or you don't understand what I am asking please leave a comment and I will try to update. I have looked long and hard for an answer, but I have found that Unreal Engine 4 hasn't got many questions that I can tailor the answer to my situation. If the answer is already in another post on this website, comment saying so and I will remove this post.
Thanks for any help you can give me :)
(This also has a itch.io page for me to quickly share to my friends so I will also credit the person who helped me there)
If I've understood your question correctly, I believe you are just asking how to check if the cube has hit the player character and not some other actor.
Instead of using an if statement as you suggested, you can just cast the Other Actor property to your first person character. If the cast is successful then it hit the character, if the cast fails, it hit something else. You can then call the damage function which you said you've already created. Below is a basic example you could use in your cube blueprint. You will also need to make sure you have a collision box surrounding your cube mesh (and your character, but I can already see that in your screenshot).
I am creating a 3-D game with a cave as the main environment. The cave is made of a large number of ring segments, one attached to the other, thus creating a currently small tunnel system.
If the Player is inside the cave, only a small part of the segments are visible. I am figuring that actually hiding the not-visible segments could save a lot of gpu time, which I need for other objects like buildings or enemies.
So what I try to do first is hiding the entire cave and then unhiding the visible segments by turning ‚node.isHidden’ true and false.
The particular nodes are being found and accessed by their names: ‚Node.childnode (withName: „XYZ003“, recursively: false).isHidden = true‘ (or false).
It works to the point where the segments are unhidden, but once I am trying to hide a previously unhidden segment, the renderer crashes with an EXC_BAD_ACCESS.
Doing the hiding on a hidden object (of course useless, but helping to understand the problem) is fine, so is unhiding unhidden segments.
Following the hint of another thread, I moved the routine into the renderer delegate so not doing the switching during the wrong time, but instead during the phase in which such changes are supposed to happen, but this did not help.
As an alternative, I did the hiding (and unhiding) by SCNActions, but I received the same result, which really puzzles me, as this would be kind of the ‚official way‘ to do it...
I also played around with the ‚recursively’ boolean, getting the same outcome (works for unhide, crashes on isHidden = true).
Then I tried to change opacity or other properties of the nodes - which worked perfectly. On the other hand, trying to remove the nodes from the parent resulted in the mentioned crash as well.
I need this to work, because older hardware could never cope with several thousand nodes (trying this, the frame rate dropped to 10fps, even without enemies around). And newer hardware might break down once the enemies appear...
My thinking is that the pointer is somehow messed up by the first unhiding (and hence the BAD_ACCESS error), so maybe an additional bonding (often seen with spritekit-routines) or another way to get the node-pointer could be the solution. On the other hand, if the pointer is broken, why can I still access all other properties? Maybe it‘s the subnodes that cause the problem - everyone of the nodes has 20 subnodes, which are supposed to change visibility, too.
Did anyone come across this behavior before me? I could not find anything during my google-research...
Hiding and unhiding nodes frequently is typically not a problem by itself. You can hide a main node and any sub-nodes of the main node will automatically hide themselves, so you shouldn't have to loop them individually.
I'm not an expert debugger and don't know your skill level, but BAD_ACCESS can mean that you tried to send a msg to a block of memory that can't execute the message or whenever the app tried to deference a corrupt pointer. Search "What Is EXC_BAD_ACCESS and How to Debug It" for a decent tutorial on some options for dealing with it.
I do my changes in the render delegate as well, but depending on the number of changes and how long they take, I sometimes use timers to control the amount of changes that can be made in a certain amount of time. That way, and after some adjustments, I'm pretty sure that I'm not bogging it down to a point where it just spirals out of control.
Structure can matter - personal preference, but I try to setup an array of classes that create individual nodes (and sub-nodes) and therefore have direct access to them. That way I'm not iterating through the whole node structure or finding nodes by name. Sometimes a lot is going on before I really have to make a modification to the node itself and so I can loop through my array of classes, check values, compare, etc. before taking action that involves the display. That also gives me a chance to remove particle systems, remove actions, set geometry = nil and update logic counters when I need to remove a node.
I'm sure opinions vary, but this has worked well for me. Once I standardized the structure, I just keep repeating the pattern.
Hope that helps
I've been using the Game State Management sample which has worked so far. I've hit a snag though: when Tombstoning, the screens are serialised; the only trouble is, the MessageBoxScreen has event handlers for Accepted and Cancelled.
What's the best way to serialise these? I did a bit of research on using Expression Trees but this seemed overly complex for what I wanted to do.
How do you serialise these? Or... What alternative approach do you use to save the state of a screen that contains delegates?
I'd definitely steer clear of attempting to serialize anything remotely resembling a lambda, or for that matter, named methods. Remember: you're storing state, and nothing else.
Depending on how far and wide your various assignments to these delegates are, you might be able to get away with maintaining a Dictionary<String, WhateverDelagateType>, serializing the keys and looking up the callbacks after deserialization.
Another thing to consider--I'm no expert, but reading between the lines it sounds as if you're working towards tombstoning a very temporary modal dialog. Do you really want that? You might be better off bringing your user right to the high scores table, or whatever follows your dialog, on his/her return.
I decided against this. I instead persists game flow as a kind of 'flow chart'.
The flow chart is declared in code and has properties 'LastShape' and 'LastResultFromShape'.
In my code, I rebuild the flow chart definitions each time, something like this:
flowChart.AddShape( "ShowSplash" );
flowChart.AddLine( "MainMenu", ()=>lastResult=="Clicked" || lastResult=="TimedOut");
flowChart.AddShape( "MainMenu");
flowChart.AddLine( #"ShowOptions", ()=>lastResult=="OptionsClicked");
flowChar.AddLine( #"ShowSplash", ()=>lastResult==#"TimedOut");
etc.etc.
The flow goes from the top down, so 'AddLine' relates to the last shape added.
After tombstoning, I just read the last shape and the last result and decide where to go in the flowchart based on that.
I am trying to get my head around how to design the following system, which I think can be defined as a finite state machine:
Say we have a pile of 16 building blocks (towers, walls, gates) together forming a castle. The player can drag the blocks to 16 places on a floorplan and if done right they will see the whole castle. All towers (there's four of them) are equal so they can go on any of the four corners. Same goes for some of the walls.
All in all there are 16 spots on the floorplan where you can put a building block and each of the spots can have 17 "states": empty + either one of the 16 building blocks. Doing some maths this leads to 17^16=a LOT of combinations.
The program starts with an empty floorplan and a pile of building blocks. It should then show a message like "build your own castle, start with the tower". When the user places a tower correctly, it should say "well done, now build all four towers". You get the idea.
Problem is: there are so many things a player can do. Put a block at the wrong place, remove a block, correctly put walls or towers all over the floorplan ignoring the directions given to them, etc.
It would be awesome if I could avoid having to use thousands of if-then statements to decide wether I should take the next step, show an error message or go back to the previous step based on what the player is doing.
How would you describe the NEXT, PREVIOUS and ERROR conditions for every step of the building sequence? Are there any design methods for this? Thanks a lot for your input.
Try to do this declaratively. Define an enum (or possibly classes) describing the kinds of blocks. Define and construct a 4x4 2D array describing the sets of permissible kinds of blocks in each position (implement the sets as lists, bitfields, whatever suits you best). Whenever a player tries to place a block in a position, check whether it is permissible against the 2D array. If you want to have particular messages for a position being correctly filled in, also put those in the same an array.
I don't know if a FSM is really what you are after: what kinds of sequencing constraints are you looking to verify? Does it matter whether towers are built first? From the rest of your description, it sounds like the above goal state description would be more suitable.