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entity show and hide #4907

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griffenliu opened this issue Jun 3, 2022 · 1 comment
Closed

entity show and hide #4907

griffenliu opened this issue Jun 3, 2022 · 1 comment
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A-Rendering Drawing game state to the screen C-Feature A new feature, making something new possible

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@griffenliu
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griffenliu commented Jun 3, 2022

What problem does this solve or what need does it fill?

I don't think it's very convenient to show and hide entities, wish there was a more convenient API like:
commands.entity(entity).show(recursive:bool);
commands.entity(entity).hide(recursive:bool);

be similar to
commands.entity(entity).despawn_recursive();

@griffenliu griffenliu added C-Feature A new feature, making something new possible S-Needs-Triage This issue needs to be labelled labels Jun 3, 2022
@james7132
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I believe #2087 attempted to tackle this. There's also #4216 that attempts to generalize transform propagation to provide similar capabilities.

@james7132 james7132 added A-Rendering Drawing game state to the screen and removed S-Needs-Triage This issue needs to be labelled labels Jun 3, 2022
@bors bors bot closed this as completed in 40d4992 Jul 15, 2022
inodentry pushed a commit to IyesGames/bevy that referenced this issue Aug 8, 2022
…support (bevyengine#5310)

# Objective

Fixes bevyengine#4907. Fixes bevyengine#838. Fixes bevyengine#5089.
Supersedes bevyengine#5146. Supersedes bevyengine#2087. Supersedes bevyengine#865. Supersedes bevyengine#5114

Visibility is currently entirely local. Set a parent entity to be invisible, and the children are still visible. This makes it hard for users to hide entire hierarchies of entities.

Additionally, the semantics of `Visibility` vs `ComputedVisibility` are inconsistent across entity types. 3D meshes use `ComputedVisibility` as the "definitive" visibility component, with `Visibility` being just one data source. Sprites just use `Visibility`, which means they can't feed off of `ComputedVisibility` data, such as culling information, RenderLayers, and (added in this pr) visibility inheritance information.

## Solution

Splits `ComputedVisibilty::is_visible` into `ComputedVisibilty::is_visible_in_view` and `ComputedVisibilty::is_visible_in_hierarchy`. For each visible entity, `is_visible_in_hierarchy` is computed by propagating visibility down the hierarchy. The `ComputedVisibility::is_visible()` function combines these two booleans for the canonical "is this entity visible" function.

Additionally, all entities that have `Visibility` now also have `ComputedVisibility`.  Sprites, Lights, and UI entities now use `ComputedVisibility` when appropriate.

This means that in addition to visibility inheritance, everything using Visibility now also supports RenderLayers. Notably, Sprites (and other 2d objects) now support `RenderLayers` and work properly across multiple views.

Also note that this does increase the amount of work done per sprite. Bevymark with 100,000 sprites on `main` runs in `0.017612` seconds and this runs in `0.01902`. That is certainly a gap, but I believe the api consistency and extra functionality this buys us is worth it. See [this thread](bevyengine#5146 (comment)) for more info. Note that bevyengine#5146 in combination with bevyengine#5114 _are_ a viable alternative to this PR and _would_ perform better, but that comes at the cost of api inconsistencies and doing visibility calculations in the "wrong" place. The current visibility system does have potential for performance improvements. I would prefer to evolve that one system as a whole rather than doing custom hacks / different behaviors for each feature slice.

Here is a "split screen" example where the left camera uses RenderLayers to filter out the blue sprite.

![image](https://user-images.githubusercontent.com/2694663/178814868-2e9a2173-bf8c-4c79-8815-633899d492c3.png)


Note that this builds directly on bevyengine#5146 and that @james7132 deserves the credit for the baseline visibility inheritance work. This pr moves the inherited visibility field into `ComputedVisibility`, then does the additional work of porting everything to `ComputedVisibility`. See my [comments here](bevyengine#5146 (comment)) for rationale. 

## Follow up work

* Now that lights use ComputedVisibility, VisibleEntities now includes "visible lights" in the entity list. Functionally not a problem as we use queries to filter the list down in the desired context. But we should consider splitting this out into a separate`VisibleLights` collection for both clarity and performance reasons. And _maybe_ even consider scoping `VisibleEntities` down to `VisibleMeshes`?.
* Investigate alternative sprite rendering impls (in combination with visibility system tweaks) that avoid re-generating a per-view fixedbitset of visible entities every frame, then checking each ExtractedEntity. This is where most of the performance overhead lives. Ex: we could generate ExtractedEntities per-view using the VisibleEntities list, avoiding the need for the bitset.
* Should ComputedVisibility use bitflags under the hood? This would cut down on the size of the component, potentially speed up the `is_visible()` function, and allow us to cheaply expand ComputedVisibility with more data (ex: split out local visibility and parent visibility, add more culling classes, etc).
---

## Changelog

* ComputedVisibility now takes hierarchy visibility into account.
* 2D, UI and Light entities now use the ComputedVisibility component.

## Migration Guide

If you were previously reading `Visibility::is_visible` as the "actual visibility" for sprites or lights, use `ComputedVisibilty::is_visible()` instead:

```rust
// before (0.7)
fn system(query: Query<&Visibility>) {
  for visibility in query.iter() {
    if visibility.is_visible {
       log!("found visible entity");
    }
  }
}

// after (0.8)
fn system(query: Query<&ComputedVisibility>) {
  for visibility in query.iter() {
    if visibility.is_visible() {
       log!("found visible entity");
    }
  }
}
``` 


Co-authored-by: Carter Anderson <mcanders1@gmail.com>
james7132 added a commit to james7132/bevy that referenced this issue Oct 28, 2022
…support (bevyengine#5310)

# Objective

Fixes bevyengine#4907. Fixes bevyengine#838. Fixes bevyengine#5089.
Supersedes bevyengine#5146. Supersedes bevyengine#2087. Supersedes bevyengine#865. Supersedes bevyengine#5114

Visibility is currently entirely local. Set a parent entity to be invisible, and the children are still visible. This makes it hard for users to hide entire hierarchies of entities.

Additionally, the semantics of `Visibility` vs `ComputedVisibility` are inconsistent across entity types. 3D meshes use `ComputedVisibility` as the "definitive" visibility component, with `Visibility` being just one data source. Sprites just use `Visibility`, which means they can't feed off of `ComputedVisibility` data, such as culling information, RenderLayers, and (added in this pr) visibility inheritance information.

## Solution

Splits `ComputedVisibilty::is_visible` into `ComputedVisibilty::is_visible_in_view` and `ComputedVisibilty::is_visible_in_hierarchy`. For each visible entity, `is_visible_in_hierarchy` is computed by propagating visibility down the hierarchy. The `ComputedVisibility::is_visible()` function combines these two booleans for the canonical "is this entity visible" function.

Additionally, all entities that have `Visibility` now also have `ComputedVisibility`.  Sprites, Lights, and UI entities now use `ComputedVisibility` when appropriate.

This means that in addition to visibility inheritance, everything using Visibility now also supports RenderLayers. Notably, Sprites (and other 2d objects) now support `RenderLayers` and work properly across multiple views.

Also note that this does increase the amount of work done per sprite. Bevymark with 100,000 sprites on `main` runs in `0.017612` seconds and this runs in `0.01902`. That is certainly a gap, but I believe the api consistency and extra functionality this buys us is worth it. See [this thread](bevyengine#5146 (comment)) for more info. Note that bevyengine#5146 in combination with bevyengine#5114 _are_ a viable alternative to this PR and _would_ perform better, but that comes at the cost of api inconsistencies and doing visibility calculations in the "wrong" place. The current visibility system does have potential for performance improvements. I would prefer to evolve that one system as a whole rather than doing custom hacks / different behaviors for each feature slice.

Here is a "split screen" example where the left camera uses RenderLayers to filter out the blue sprite.

![image](https://user-images.githubusercontent.com/2694663/178814868-2e9a2173-bf8c-4c79-8815-633899d492c3.png)


Note that this builds directly on bevyengine#5146 and that @james7132 deserves the credit for the baseline visibility inheritance work. This pr moves the inherited visibility field into `ComputedVisibility`, then does the additional work of porting everything to `ComputedVisibility`. See my [comments here](bevyengine#5146 (comment)) for rationale. 

## Follow up work

* Now that lights use ComputedVisibility, VisibleEntities now includes "visible lights" in the entity list. Functionally not a problem as we use queries to filter the list down in the desired context. But we should consider splitting this out into a separate`VisibleLights` collection for both clarity and performance reasons. And _maybe_ even consider scoping `VisibleEntities` down to `VisibleMeshes`?.
* Investigate alternative sprite rendering impls (in combination with visibility system tweaks) that avoid re-generating a per-view fixedbitset of visible entities every frame, then checking each ExtractedEntity. This is where most of the performance overhead lives. Ex: we could generate ExtractedEntities per-view using the VisibleEntities list, avoiding the need for the bitset.
* Should ComputedVisibility use bitflags under the hood? This would cut down on the size of the component, potentially speed up the `is_visible()` function, and allow us to cheaply expand ComputedVisibility with more data (ex: split out local visibility and parent visibility, add more culling classes, etc).
---

## Changelog

* ComputedVisibility now takes hierarchy visibility into account.
* 2D, UI and Light entities now use the ComputedVisibility component.

## Migration Guide

If you were previously reading `Visibility::is_visible` as the "actual visibility" for sprites or lights, use `ComputedVisibilty::is_visible()` instead:

```rust
// before (0.7)
fn system(query: Query<&Visibility>) {
  for visibility in query.iter() {
    if visibility.is_visible {
       log!("found visible entity");
    }
  }
}

// after (0.8)
fn system(query: Query<&ComputedVisibility>) {
  for visibility in query.iter() {
    if visibility.is_visible() {
       log!("found visible entity");
    }
  }
}
``` 


Co-authored-by: Carter Anderson <mcanders1@gmail.com>
ItsDoot pushed a commit to ItsDoot/bevy that referenced this issue Feb 1, 2023
…support (bevyengine#5310)

# Objective

Fixes bevyengine#4907. Fixes bevyengine#838. Fixes bevyengine#5089.
Supersedes bevyengine#5146. Supersedes bevyengine#2087. Supersedes bevyengine#865. Supersedes bevyengine#5114

Visibility is currently entirely local. Set a parent entity to be invisible, and the children are still visible. This makes it hard for users to hide entire hierarchies of entities.

Additionally, the semantics of `Visibility` vs `ComputedVisibility` are inconsistent across entity types. 3D meshes use `ComputedVisibility` as the "definitive" visibility component, with `Visibility` being just one data source. Sprites just use `Visibility`, which means they can't feed off of `ComputedVisibility` data, such as culling information, RenderLayers, and (added in this pr) visibility inheritance information.

## Solution

Splits `ComputedVisibilty::is_visible` into `ComputedVisibilty::is_visible_in_view` and `ComputedVisibilty::is_visible_in_hierarchy`. For each visible entity, `is_visible_in_hierarchy` is computed by propagating visibility down the hierarchy. The `ComputedVisibility::is_visible()` function combines these two booleans for the canonical "is this entity visible" function.

Additionally, all entities that have `Visibility` now also have `ComputedVisibility`.  Sprites, Lights, and UI entities now use `ComputedVisibility` when appropriate.

This means that in addition to visibility inheritance, everything using Visibility now also supports RenderLayers. Notably, Sprites (and other 2d objects) now support `RenderLayers` and work properly across multiple views.

Also note that this does increase the amount of work done per sprite. Bevymark with 100,000 sprites on `main` runs in `0.017612` seconds and this runs in `0.01902`. That is certainly a gap, but I believe the api consistency and extra functionality this buys us is worth it. See [this thread](bevyengine#5146 (comment)) for more info. Note that bevyengine#5146 in combination with bevyengine#5114 _are_ a viable alternative to this PR and _would_ perform better, but that comes at the cost of api inconsistencies and doing visibility calculations in the "wrong" place. The current visibility system does have potential for performance improvements. I would prefer to evolve that one system as a whole rather than doing custom hacks / different behaviors for each feature slice.

Here is a "split screen" example where the left camera uses RenderLayers to filter out the blue sprite.

![image](https://user-images.githubusercontent.com/2694663/178814868-2e9a2173-bf8c-4c79-8815-633899d492c3.png)


Note that this builds directly on bevyengine#5146 and that @james7132 deserves the credit for the baseline visibility inheritance work. This pr moves the inherited visibility field into `ComputedVisibility`, then does the additional work of porting everything to `ComputedVisibility`. See my [comments here](bevyengine#5146 (comment)) for rationale. 

## Follow up work

* Now that lights use ComputedVisibility, VisibleEntities now includes "visible lights" in the entity list. Functionally not a problem as we use queries to filter the list down in the desired context. But we should consider splitting this out into a separate`VisibleLights` collection for both clarity and performance reasons. And _maybe_ even consider scoping `VisibleEntities` down to `VisibleMeshes`?.
* Investigate alternative sprite rendering impls (in combination with visibility system tweaks) that avoid re-generating a per-view fixedbitset of visible entities every frame, then checking each ExtractedEntity. This is where most of the performance overhead lives. Ex: we could generate ExtractedEntities per-view using the VisibleEntities list, avoiding the need for the bitset.
* Should ComputedVisibility use bitflags under the hood? This would cut down on the size of the component, potentially speed up the `is_visible()` function, and allow us to cheaply expand ComputedVisibility with more data (ex: split out local visibility and parent visibility, add more culling classes, etc).
---

## Changelog

* ComputedVisibility now takes hierarchy visibility into account.
* 2D, UI and Light entities now use the ComputedVisibility component.

## Migration Guide

If you were previously reading `Visibility::is_visible` as the "actual visibility" for sprites or lights, use `ComputedVisibilty::is_visible()` instead:

```rust
// before (0.7)
fn system(query: Query<&Visibility>) {
  for visibility in query.iter() {
    if visibility.is_visible {
       log!("found visible entity");
    }
  }
}

// after (0.8)
fn system(query: Query<&ComputedVisibility>) {
  for visibility in query.iter() {
    if visibility.is_visible() {
       log!("found visible entity");
    }
  }
}
``` 


Co-authored-by: Carter Anderson <mcanders1@gmail.com>
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