# Objective
Users should be able to configure depth load operations on cameras. Currently every camera clears depth when it is rendered. But sometimes later passes need to rely on depth from previous passes.
## Solution
This adds the `Camera3d::depth_load_op` field with a new `Camera3dDepthLoadOp` value. This is a custom type because Camera3d uses "reverse-z depth" and this helps us record and document that in a discoverable way. It also gives us more control over reflection + other trait impls, whereas `LoadOp` is owned by the `wgpu` crate.
```rust
commands.spawn_bundle(Camera3dBundle {
camera_3d: Camera3d {
depth_load_op: Camera3dDepthLoadOp::Load,
..default()
},
..default()
});
```
### two_passes example with the "second pass" camera configured to the default (clear depth to 0.0)
### two_passes example with the "second pass" camera configured to "load" the depth
---
## Changelog
### Added
* `Camera3d` now has a `depth_load_op` field, which can configure the Camera's main 3d pass depth loading behavior.
# Objective
Users should be able to render cameras to specific areas of a render target, which enables scenarios like split screen, minimaps, etc.
Builds on the new Camera Driven Rendering added here: #4745Fixes: #202
Alternative to #1389 and #3626 (which are incompatible with the new Camera Driven Rendering)
## Solution
Cameras can now configure an optional "viewport", which defines a rectangle within their render target to draw to. If a `Viewport` is defined, the camera's `CameraProjection`, `View`, and visibility calculations will use the viewport configuration instead of the full render target.
```rust
// This camera will render to the first half of the primary window (on the left side).
commands.spawn_bundle(Camera3dBundle {
camera: Camera {
viewport: Some(Viewport {
physical_position: UVec2::new(0, 0),
physical_size: UVec2::new(window.physical_width() / 2, window.physical_height()),
depth: 0.0..1.0,
}),
..default()
},
..default()
});
```
To account for this, the `Camera` component has received a few adjustments:
* `Camera` now has some new getter functions:
* `logical_viewport_size`, `physical_viewport_size`, `logical_target_size`, `physical_target_size`, `projection_matrix`
* All computed camera values are now private and live on the `ComputedCameraValues` field (logical/physical width/height, the projection matrix). They are now exposed on `Camera` via getters/setters This wasn't _needed_ for viewports, but it was long overdue.
---
## Changelog
### Added
* `Camera` components now have a `viewport` field, which can be set to draw to a portion of a render target instead of the full target.
* `Camera` component has some new functions: `logical_viewport_size`, `physical_viewport_size`, `logical_target_size`, `physical_target_size`, and `projection_matrix`
* Added a new split_screen example illustrating how to render two cameras to the same scene
## Migration Guide
`Camera::projection_matrix` is no longer a public field. Use the new `Camera::projection_matrix()` method instead:
```rust
// Bevy 0.7
let projection = camera.projection_matrix;
// Bevy 0.8
let projection = camera.projection_matrix();
```
