Flix - Procedural training and Movie making

[dlannan]

Ok. Some more fun. Im running out of resources alot (because I need to build a mesh hierarchy on the fly at runtime) and there are many forum posts regarding this where its explained that instanced factory go’s share their attached components (like mesh, etc). This makes sense, since most of the time you want to instance an object, and have it as a duplicate of some mesh or sprite.

The problem with a runtime scene hierarchy, I need to prebuild a pool of objects with meshes (I have a meshpool folder with 100 x gos, mesh buffers, and 4 pbr texture files for each … yes its a little crazy. I have some script that helps me build it, so I can scale it up. However, I just tried a glb anim, and because it has over 100 parts (bones etc) it automatically uses all of my pool. Now. I could just make 1000 x resources (which is kinda nuts) or, more sensible, move the rendering out to another method, where I can easily do this (sharing assets and so on).

Sadly… this all means alot more work to get something more usable. But on the flipside, I can use a back end native extension renderer that should give me highly advanced rendering features. Going to spend a few days working on some design concepts and tests. This might be actually quite interesting.

[britzl]

@dlannan

I have a meshpool folder with 100 x gos, mesh buffers, and 4 pbr texture files for each

But what remains for this to be completely dynamic so that you don’t have to create all of these up-front? I’m trying to understand what we could do to simplify life for you.

[dlannan]

As per a number of other threads on the forums, there is no real way to create a new GameObject, that can then have a component (new also) added to it. My understanding (from reading the various threads) is that factories create instances, and thus data for them is shared (some is not, like position etc but components like meshes are shared).

I did try using factories, but as expected on instance 2… modifying the mesh on the instanced go crashed the running app. I get why this is, and I dont know how deep a problem that would be to add. My meshpool was a way around that, but with a tool that will potentially have hundreds of characters, and objects in the scene, I dont think that will scale well at all

And, again, this is probably not a common use case. I dont expect a game engine to necessarily support this kind of resource usage, thus I dont really want to request it
I’ll find a way around it - there are many different things I want to try over the next few days. For example:

• generate a collapsed mesh (at runtime) by composing in the transforms for more static objects.
• use something like ozz animation lib to handle anim, thus the bones are not needing to be managed in the go structure itself
• try a simple backend renderer that has some of these (like maybe sokol or something) that I can layer in as a render pass into Defold.
• use another engine entirely for the render pass embedded in the app which would be nuts, but Ive done it with other systems before (like C# WPF running Unigine within it ).

There some interesting things to look at. Will draw up some ideas, throw away any that just are non-sensical, and knock out some tests for the remaining ones to validate the design. Then move on

[d954mas]

Yes you can’t create go with components in runtime. You should use factories.

But you can create buffer resource for mesh in runtime.

API reference (resource)

local function water_create_default_native_buffer()
	return buffer.create(1, {
		{ name = hash("position"), type = buffer.VALUE_TYPE_FLOAT32, count = 3 },
		{ name = hash("normal"), type = buffer.VALUE_TYPE_FLOAT32, count = 3 },
		{ name = hash("texcoord0"), type = buffer.VALUE_TYPE_FLOAT32, count = 2 },
	})
end

---@return BufferResourceData
function M.water_create_new_buffer()
	M.water.idx = M.water.idx + 1
	local name = "/runtime_buffer_water_" .. M.water.idx .. ".bufferc"
	local new_buffer = resource.create_buffer(name, { buffer = water_create_default_native_buffer() })

	---@class BufferResourceData
	local buffer_resource = {}
	buffer_resource.name = name
	buffer_resource.buffer = new_buffer
	buffer_resource.free = false

	return buffer_resource
end

go.set(e.water_go.mesh, "vertices", e.water_buffer.buffer)

[dlannan]

Im not sure you have understood the problem. I have a geomextension lib (shared a couple yrs ago) that does this. But you cannot apply new meshes to instances from a factory. I’ve tried this many times over the years because components cant be added to the instance at runtime.

The buffers would be more useful (for this instance) if I could create a mesh component and attach it to a go instance. That would be a nice way to do this, but I also suspect its a much more complicated problem since resources are all precompiled at build time.

Sorry that was a little unclear. Specifically, if I instance a go with an attached mesh, that mesh buffer resource handle is shared with all instances. Thus, you cannot replace the mesh with a buffer. If you attempt to do so, on the second instance you try it on, it can crash (because of the reference held from the first one). This was mentioned above.

[dlannan]

For some references to the above. Here are some of the forum posts that relate to this. Some quite old, but this is kinda a known limitation for runtime resource usage:

Arbitrary scene graph hierarchy at runtime

Hi, I’ve just started using Defold, and it is a very nice engine, indeed :). I have a (million, but let’s start with this one) question: I want to create an arbitrary hierarchy of objects at runtime, and what I’ve done so far is creating a factory that spawns empty GameObjects that I then move around with “set_parent”. Is there any way of creating those empty GameObjects without having to create a factory with an empty .go file attached? It seems like a hack Thanks in advance!

Scriptable GameObject creation (DEF-2096)

As commented here, it will be useful to be able to create (empty) GameObjects on the fly to take advantage of the scene graph at runtime. Maybe something like factory.create_game_object([parent]) or similar (I don’t know the API well enough yet to know about naming or structure, but hopefully you get the idea :D)

Is it possible to create collision object at runtime?

I’m new to Defold, and try to create a brick game for learning purpose. I plan to bounce the ball if it hits the edges of window (left, right, top, bottom). So I placed four boxes at the edges, and bounce the ball if a hit message is posted. That works great, but now I want to adapt the window size, so the collision object cannot be placed at fixed positions, so I figure I could create those boxes inside collision object at runtime. But after a wide search on both Defold document, forum and …

Mesh Component

I’ve been trying to make a gameobject, that generates a vertex buffer on init. That works fine. The problem is, whenever I create another another instance of the go (either through factory or just plonking more in in the collection editor), the previous ones get the same vertices. I’m guessing it’s because all the meshes have the same .buffer file, and it’s that that is getting updated. Is it possible to create instances of a go with different vertex buffers at runtime somehow?

And there are other related ones.

[dlannan]

Also just for some more clarity. My geom extenstion (this one a little modified) does the following when assigning new buffers to a mesh.

------------------------------------------------------------------------------------------------------------

function geom:makeMesh( goname, indices, verts, uvs, normals )

	if(#indices <= 0) then 
		print("[Error] Invalid indices count.")
		return 
	end
	
	local res = go.get(goname, "vertices")
	local iverts = #indices

	local meshdata = {}
	-- positions are required (should assert or something)
	tinsert(meshdata, { name = hash("position"), type=buffer.VALUE_TYPE_FLOAT32, count = 3 } )
	if(normals) then tinsert(meshdata, { name = hash("normal"), type=buffer.VALUE_TYPE_FLOAT32, count = 3 } ) end
	if(uvs) then tinsert(meshdata, { name = hash("texcoord0"), type=buffer.VALUE_TYPE_FLOAT32, count = 2 } ) end
	
	local meshbuf = buffer.create(iverts, meshdata)

	geomextension.setbufferbytesfromtable( meshbuf, "position", indices, verts )
	if(normals) then geomextension.setbufferbytesfromtable( meshbuf, "normal", indices, normals ) end
	if(uvs) then geomextension.setbufferbytesfromtable( meshbuf, "texcoord0", indices, uvs ) end 
		
	-- set the buffer with the vertices on the mesh
	resource.set_buffer(res, meshbuf)
end

------------------------------------------------------------------------------------------------------------

So the problem isnt being able to generate mesh buffer data, but trying to replace the mesh component handle so that it has a new handle. This might be doable in C++ but I’m not certain of that.
If there are examples/methods that can do this, I would be very welcome to suggestions.

I think this specific comment shows the main problem:

Mesh Component

It is important to note that you update the resource in your example. If all meshes use that same resource, then it won’t work as you intended. Instead, you can create a new buffer resource dynamically, and assign it: local newBuff = buffer.create(...) -- as you do now local resource_name = "/my_cloned_buffer.bufferc" -- make this unique for each resource! local buffer_resource = reource.create_buffer(resource_name, { buffer = newBuff }) go.set(url, "vertices", buffer_resource) -- replace i…

local resource_name = "/my_cloned_buffer.bufferc" -- make this unique for each resource!
This means there needs to be a physical resource file for each res that needs to be attached/modified for each instance.

Note: The code includes some helper funcs that copy tables into buffer data for consumption by the buffer.

[d954mas]

1)You have factory.
Factory create go with mesh.
2) From url to this mesh. You can get vertices.

local res = go.get("#mesh", "vertices")

If you print vertices you will get something like this
“vertices: “/world/game/go/chunk/chunk.buffer”\n”

3)You can change this buffer. Now all meshes that have vertices “vertices: “/world/game/go/chunk/chunk.buffer”\n” is changed.

resource.set_buffer(res, buf)

4)Also you can change vertices field for you mesh instance.

API reference (resource)

    -- assign cloned buffer to a mesh component
go.set("/go#mesh", "vertices", buf)```

So for example. You have one factory. You create 10 go. For every go you change vertices. 
Now you have 10 unique meshes with different meshes.

[d954mas]

@dlannan

local resource_name = "/my_cloned_buffer.bufferc" -- make this unique for each resource!
This means there needs to be a physical resource file for each res that needs to be attached/modified for each instance.

No, this is only name. It was physical resource if this buffer is created by bob when build game.

But you can create this resources in runtime. You will only need string name with .bufferc ending.
This will not create a new file. This .bufferc will be in memory

[dlannan]

Ok. Im not sure I understand. How do I make new resource buffers at runtime
Those other bufferc files do not exist.

If you look at my code above. This is exactly what you suggest, but you cannot change the mesh because the resource (go.get("#mesh", “vertices”) ) is shared on all instanced go’s.

[dlannan]

@d954mas

But you can create this resources in runtime. You will only need string name with .bufferc ending.
This will not create a new file. This .bufferc will be in memory

Hrm. This is only a url handle? So in the code above I should be able to set res = “randomname.bufferc” ?

< Update > Just tried this (in above code)

local res = "testbuffer_"..string.format("%d", ctr)..".bufferc" -- go.get(goname, "vertices")

Error:

Not really sure how this could work.

[d954mas]

Yes, look at resource.create_buffer()

API reference (resource)

Defold 1.4.3 has been released

Release notes Summary CHANGE: (#7240) Update NDK 25 LTS (r25b) NEW: (#7264) Factory dynamic prototype NEW: (#7029) Add timer.get_info() function NEW: (#7266) Update Android SDK (33.0.1 - Android 13 - API 33) NEW: (#7296) Document ports and services NEW: (#6902) Shader include support NEW: (#7329) Update Screen Orientation options by Default on iOS and Android NEW: (#7214) Create buffer in runtime FIX: (#7312) Improve GUI modification performance FIX: (#7315) Fix issue with component…

NEW: (#7214 ) Create buffer in runtime
Added new function resource.create_buffer to create buffer resources dynamically in runtime. The function takes a buffer object created by other buffer resources, from the C api or via the lua buffer.create function.

[dlannan]

Again, I think you are not really understanding? I can create buffers no problem. Look at the above code please. It does exactly what you suggest.

However, the problem is attaching those buffers to an instanced go. If you use:
local res = go.get("#mesh", "vertices")
this fetches a resource handle that is a compiled bufferc. Which is done at build time.

If (and I think this is what you are saying) you can make a new resource at runtime with a valid resource handle then that is what should be used. However, just making up a name wont work, because the registry wont have that file? Maybe in C++ I can add something that registers a new file resource that then can be used? Again, it is not clear how your example could possibly work.

Note: In the api there isnt really a “create resource” call that generates a new runtime resource for use. The closest thing I can see is in the C++ api where there is an AddFile, but Im not sure that is whats needed.

API reference (dmResource)

More Notes: I was thinking probably the easiest thing that would potentially provide a simple solve is a copy method in the C++ api, that allows the copying of a resource in mem. And then this would be fairly simple to apply (maybe?)

[d954mas]

@dlannan

However, just making up a name wont work, because the registry wont have that file? Maybe in C++ I can add something that registers a new file resource that then can be used? Again, it is not clear how your example could possibly work.

You don’t need new file.

You create runtime resource. This is in memory.
This resource will be alived while you have references for it.(If I understand right)

In this example buffer is clonned. But you can use new buffer.

When you create a new resource, you set content for it. So you don’t need file.

local res = resource.get_buffer("/my_buffer_path.bufferc")
    -- create a cloned buffer resource from another resource buffer
    local buf = reource.create_buffer("/my_cloned_buffer.bufferc", { buffer = res })

This is video of my voxels game. I use one factory for chunk. And I can have unique meshes for every chunk. I am creating new buffer resources in runtime.

Mine Universe Week 4

[d954mas]

Try it, when you write some code you will see how it worked:)

[dlannan]

Hrm. I think you are using different methods. This might be the problem. Im using buffer.create, which is different to resource.create_buffer.

Just to be clear, are you generating instanced go’s at runtime each with a separate mesh objects? Or are you created one mesh, with additional/other buffers on that mesh component? Because that is already something Im doing.

[dlannan]

You absolute bloody legend!!! Thankyou. It was the commands I was using!!!
Ive changed it to this:

------------------------------------------------------------------------------------------------------------
local ctr = 0
function geom:makeMesh( goname, indices, verts, uvs, normals )

	if(#indices <= 0) then 
		print("[Error] Invalid indices count.")
		return 
	end
	
	--	local mesh = resource.load("/assets/gotemplate/temp.mesh")
	pprint(goname)
	local res = resource.get_buffer(go.get(goname, "vertices"))	
	-- create a cloned buffer resource from another resource buffer
	local newres = resource.create_buffer("/testbuffer_"..string.format("%d", ctr)..".bufferc", { buffer = res })	
	ctr = ctr + 1
	pprint(newres)
	local iverts = #indices

	local meshdata = {}
	-- positions are required (should assert or something)
	tinsert(meshdata, { name = hash("position"), type=buffer.VALUE_TYPE_FLOAT32, count = 3 } )
	if(normals) then tinsert(meshdata, { name = hash("normal"), type=buffer.VALUE_TYPE_FLOAT32, count = 3 } ) end
	if(uvs) then tinsert(meshdata, { name = hash("texcoord0"), type=buffer.VALUE_TYPE_FLOAT32, count = 2 } ) end
	--{ name = hash("color0"), type=buffer.VALUE_TYPE_FLOAT32, count = 4 }
	
	local meshbuf = buffer.create(iverts, meshdata)

	geomextension.setbufferbytesfromtable( meshbuf, "position", indices, verts )
	if(normals) then geomextension.setbufferbytesfromtable( meshbuf, "normal", indices, normals ) end
	if(uvs) then geomextension.setbufferbytesfromtable( meshbuf, "texcoord0", indices, uvs ) end 
		
	-- set the buffer with the vertices on the mesh
	resource.set_buffer(newres, meshbuf)
	go.set(goname, "vertices", newres)
end

------------------------------------------------------------------------------------------------------------

And it is mostly working - need to obviously change the ctr naming. Will do some testing, I will need to pump up the buffer and mesh limits now too. Thankyou for helping, I was really struggling with how you could possibly have done it without a resource!

Thanks again. And I really appreciate the patience and help.
Also, I apologize for not realizing the code I was using was different. Very sorry. Thankyou again.

[dlannan]

@d954mas - Again. Cant thank you enough. It looks like this should work.
Im now having material instancing issues, but thats because many of my naming conventions have moved around so they are referencing the wrong objects. A little piccy:

Yes thats an MQ-9 in the bg.

[d954mas]

Welcome, I Iike to read your posts, you make cool things​:+1:

[dlannan]

Thanks mate. You make some astonishing projects yourself. You are quite an inspirational developer, so thanks if it hasnt already been said too much