Add Active Camera geometry node #105761

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opened 2023-03-14 13:04:53 +01:00 by Hans Goudey · 19 comments

Hans Goudey commented

2023-03-14 13:04:53 +01:00

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Since geometry nodes is always processed in the context of a scene (at least it is now), there is typically a single camera object that's currently used for rendering. It can be useful to extract information from it, and the first step is just being able to access its transform.

https://blender.community/c/rightclickselect/VQ2W/

Add a node that outputs the active camera object. Users can then use the object info node to retrieve data about the object's transform. The task includes investigating and adding dependencies between the two objects so that geometry nodes reevaluates when the active camera is moved. That is done in process_nodes_for_depsgraph.

Since geometry nodes is always processed in the context of a scene (at least it is now), there is typically a single camera object that's currently used for rendering. It can be useful to extract information from it, and the first step is just being able to access its transform. https://blender.community/c/rightclickselect/VQ2W/ Add a node that outputs the active camera object. Users can then use the object info node to retrieve data about the object's transform. The task includes investigating and adding dependencies between the two objects so that geometry nodes reevaluates when the active camera is moved. That is done in `process_nodes_for_depsgraph`.

Hans Goudey added the

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Nodes & Physics

labels 2023-03-14 13:04:54 +01:00

Hans Goudey added this to the Nodes & Physics project 2023-03-14 13:04:55 +01:00

Iliya Katueshenock commented

2023-03-14 13:07:42 +01:00

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Still, how to handle cases when there are several cameras and they switch?

Still, how to handle cases when there are several cameras and they switch?

Piyush Aniruddha Udhao commented

2023-03-14 18:11:01 +01:00

First-time contributor

I would like to pick up this issue! Just a heads up though, I have college exams from tomorrow till friday, ie, from 15th to 17th March.
Will it be okay if I can submit a PR by the 20th?

I would like to pick up this issue! Just a heads up though, I have college exams from tomorrow till friday, ie, from 15th to 17th March. Will it be okay if I can submit a PR by the 20th?

Iliya Katueshenock commented

2023-03-14 18:12:34 +01:00

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@Piyush-Aniruddha-Udhao Whenever you want, it's not urgent.

@Piyush-Aniruddha-Udhao Whenever you want, it's not urgent.

Piyush Aniruddha Udhao commented

2023-03-14 18:34:25 +01:00

First-time contributor

That is done in process_nodes_for_depsgraph.

Doubt 1: Does it imply that we have to make changes in process_nodes_for_depsgraph, or use this function in our node implementation?

The task includes investigating and adding dependencies between the two objects so that geometry nodes reevaluates when the active camera is moved.

Doubt 2: What two objects, is it the camera and the node object?

> That is done in `process_nodes_for_depsgraph`. Doubt 1: Does it imply that we have to make changes in `process_nodes_for_depsgraph`, or use this function in our node implementation? > The task includes investigating and adding dependencies between the two objects so that geometry nodes reevaluates when the active camera is moved. Doubt 2: What two objects, is it the camera and the node object?

Iliya Katueshenock commented

2023-03-14 18:45:44 +01:00

Member

You need at least basic knowledge of the dependency graph, this task has become more difficult
But to simplify, take a look at node_needs_own_transform_relation and add analog for new node

You need at least basic knowledge of the dependency graph, this task has become more difficult But to simplify, take a look at `node_needs_own_transform_relation` and add analog for new node

Piyush Aniruddha Udhao commented

2023-03-14 19:00:34 +01:00

First-time contributor

Okay, I will research dependency graph properly.

take a look at node_needs_own_transform_relation and add analog for new node

Understood! Thank you :>

Okay, I will research dependency graph properly. > take a look at node_needs_own_transform_relation and add analog for new node Understood! Thank you :>

Piyush Aniruddha Udhao commented

2023-03-18 05:05:43 +01:00

First-time contributor

Hey @mod_moder, do you know any closed issue that had to create a new geometry node? I'm trying to find one, so that I can see how new nodes are built.

Hey @mod_moder, do you know any closed issue that had to create a new geometry node? I'm trying to find one, so that I can see how new nodes are built.

Iliya Katueshenock commented

2023-03-18 13:21:16 +01:00

Member

@Piyush-Aniruddha-Udhao An example of the simplest node: #104602

@Piyush-Aniruddha-Udhao An example of the simplest node: https://projects.blender.org/blender/blender/pulls/104602

Piyush Aniruddha Udhao commented

2023-03-18 14:19:50 +01:00

First-time contributor

thanks a lot!

thanks a lot!

Piyush Aniruddha Udhao commented

2023-03-18 15:47:41 +01:00

First-time contributor

@mod_moder could you please explain what NODE_STORAGE_FUNCS() does? I see that it is used before node_declare() by nodes whose structs were declared in DNA_node_types.h. Is it required to call it for the active camera node? Could you explain the difference between the nodes that use it and the nodes that don't?

@mod_moder could you please explain what `NODE_STORAGE_FUNCS()` does? I see that it is used before `node_declare()` by nodes whose structs were declared in `DNA_node_types.h`. Is it required to call it for the active camera node? Could you explain the difference between the nodes that use it and the nodes that don't?

Iliya Katueshenock commented

2023-03-18 17:01:20 +01:00

Member

Define the definition of the data structure to use for bnode.storage, you don't need this if you don't want to have any properties for the node. For me, it's better to use custom1 if that's enough

Define the definition of the data structure to use for bnode.storage, you don't need this if you don't want to have any properties for the node. For me, it's better to use custom1 if that's enough

YimingWu commented

2023-03-20 07:57:16 +01:00

Member

I'll keep an eye on this too.

I'll keep an eye on this too.

dbsc referenced this issue

2023-03-24 01:55:54 +01:00

Add Active Camera geometry node #106065

DorianB commented

2023-04-18 17:29:55 +02:00

First-time contributor

Hi everyone
This design was implemented as a plugin node by StrikeDigital, it could become a "camera info" node with a few more useful informations. If interested by an implementation please poke me, looks like a good node to learn blender source code

https://devtalk.blender.org/t/extra-nodes-for-geometrynodes/20942

Hi everyone This design was implemented as a plugin node by StrikeDigital, it could become a "camera info" node with a few more useful informations. If interested by an implementation please poke me, looks like a good node to learn blender source code ![img](https://projects.blender.org/attachments/47fa2805-f31a-467a-9420-60bf37b53aec) https://devtalk.blender.org/t/extra-nodes-for-geometrynodes/20942

4f0358a68fe7ef359460f3b43ff2383f4e1338f8.png

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DorianB referenced this issue

2023-04-18 17:45:02 +02:00

Add Active Camera geometry node #106065

JessJ-1 commented

2023-04-21 23:05:20 +02:00

First-time contributor

Wasted opportunity to have a Scene Info node
active camera is part of blender scene description

Wasted opportunity to have a Scene Info node active camera is part of blender scene description

4f0358a68fe7ef359460f3b43ff2383f4e1338f8.jpg

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Iliya Katueshenock self-assigned this 2023-06-13 14:22:22 +02:00

Iliya Katueshenock removed their assignment 2023-06-13 18:17:34 +02:00

Ilja Razinkov commented

2023-06-19 21:06:10 +02:00

First-time contributor

Is it possible also have vector conversions from world coords to camera and back?
Same conversion that is possible in material shaders "Vector convert" node

Is it possible also have vector conversions from world coords to camera and back? Same conversion that is possible in material shaders "Vector convert" node

YimingWu commented

2023-06-21 10:59:56 +02:00

Member

@IPv6 It is possible, however to convert into a camera will require more than two vectors (pos, dir), it can look clumsy for the know and a "camera type" will not have much of any use alone in the context of Geometry Node. I'm thinking maybe a "Edit active camera" node is more useful, which then allows you to plug in those arguments to affect the view of the final render.

I'm not sure if we can allow changing of FOV since it's hooked to the output dimension, this might be provided as a read only value.

@IPv6 It is possible, however to convert into a camera will require more than two vectors (pos, dir), it can look clumsy for the know and a "camera type" will not have much of any use alone in the context of Geometry Node. I'm thinking maybe a "Edit active camera" node is more useful, which then allows you to plug in those arguments to affect the view of the final render. I'm not sure if we can allow changing of FOV since it's hooked to the output dimension, this might be provided as a read only value.

Ilja Razinkov commented

2023-06-21 11:18:55 +02:00

First-time contributor

@IPv6 It is possible, however to convert into a camera will require more than two vectors (pos, dir), it can look clumsy for the know and a "camera type" will not have much of any use alone in the context of Geometry Node. I'm thinking maybe a "Edit active camera" node is more useful, which then allows you to plug in those arguments to affect the view of the final render.

I see. Just for the context - for my usecases vector-based conversions are more useful than affecting camera itself. Currently there is no way to alter mesh geometry relative to "screen" - but there is a lot of effects that would benefit from it. To name a few

"interface-like" elements in animation that stay (or smoothly attaching themselves) to top/side of camera frame
simple "cloth depenetration" to automaticaly fight easy cases of selfintersections when it is sufficient to move part of geometry toward camera (with respect to fov/ortho/etc, without changing visual position)
screen-spaced effects that "just works" without manual calculations and positional setups in scene

Some of this can be made via material, some via constraints, but all this add additional complications. Making this via GN would ease some indie devs pains

> @IPv6 It is possible, however to convert into a camera will require more than two vectors (pos, dir), it can look clumsy for the know and a "camera type" will not have much of any use alone in the context of Geometry Node. I'm thinking maybe a "Edit active camera" node is more useful, which then allows you to plug in those arguments to affect the view of the final render. I see. Just for the context - for my usecases vector-based conversions are more useful than affecting camera itself. Currently there is no way to alter mesh geometry relative to "screen" - but there is a lot of effects that would benefit from it. To name a few - "interface-like" elements in animation that stay (or smoothly attaching themselves) to top/side of camera frame - simple "cloth depenetration" to automaticaly fight easy cases of selfintersections when it is sufficient to move part of geometry toward camera (with respect to fov/ortho/etc, without changing visual position) - screen-spaced effects that "just works" without manual calculations and positional setups in scene Some of this can be made via material, some via constraints, but all this add additional complications. Making this via GN would ease some indie devs pains

Iliya Katueshenock commented

2023-06-21 12:40:30 +02:00

Member

@ChengduLittleA @IPv6 Global-Local transformation isn't related with this task.

@ChengduLittleA @IPv6 Global-Local transformation isn't related with this task.

YimingWu commented

2023-06-23 17:05:26 +02:00

Member

Global-Local transformation isn't related with this task.

No it doesn't need to have that. Here we could consider the value being always global.

> Global-Local transformation isn't related with this task. No it doesn't need to have that. Here we could consider the value being always global.

Douglas Paul referenced this issue

2023-10-09 00:03:16 +02:00

Geometry Nodes: Add Active Camera input node #113431

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