Trait bevy::render::render_phase::RenderCommand
pub trait RenderCommand<P>where
P: PhaseItem,{
type Param: SystemParam + 'static;
type ViewWorldQuery: ReadOnlyWorldQuery;
type ItemWorldQuery: ReadOnlyWorldQuery;
// Required method
fn render<'w>(
item: &P,
view: <<Self::ViewWorldQuery as WorldQuery>::ReadOnly as WorldQuery>::Item<'w>,
entity: <<Self::ItemWorldQuery as WorldQuery>::ReadOnly as WorldQuery>::Item<'w>,
param: <Self::Param as SystemParam>::Item<'w, '_>,
pass: &mut TrackedRenderPass<'w>
) -> RenderCommandResult;
}Expand description
RenderCommands are modular standardized pieces of render logic that can be composed into
Draw functions.
To turn a stateless render command into a usable draw function it has to be wrapped by a
RenderCommandState.
This is done automatically when registering a render command as a Draw function via the
AddRenderCommand::add_render_command method.
Compared to the draw function the required ECS data is fetched automatically
(by the RenderCommandState) from the render world.
Therefore the three types Param,
ViewWorldQuery and
ItemWorldQuery are used.
They specify which information is required to execute the render command.
Multiple render commands can be combined together by wrapping them in a tuple.
Example
The DrawPbr draw function is created from the following render command
tuple. Const generics are used to set specific bind group locations:
ⓘ
pub type DrawPbr = (
SetItemPipeline,
SetMeshViewBindGroup<0>,
SetStandardMaterialBindGroup<1>,
SetTransformBindGroup<2>,
DrawMesh,
);Required Associated Types§
type Param: SystemParam + 'static
type Param: SystemParam + 'static
Specifies the general ECS data (e.g. resources) required by RenderCommand::render.
When fetching resources, note that, due to lifetime limitations of the Deref trait,
SRes::into_inner must be called on each SRes reference in the
RenderCommand::render method, instead of being automatically dereferenced as is the
case in normal systems.
All parameters have to be read only.
type ViewWorldQuery: ReadOnlyWorldQuery
type ViewWorldQuery: ReadOnlyWorldQuery
Specifies the ECS data of the view entity required by RenderCommand::render.
The view entity refers to the camera, or shadow-casting light, etc. from which the phase item will be rendered from. All components have to be accessed read only.
type ItemWorldQuery: ReadOnlyWorldQuery
type ItemWorldQuery: ReadOnlyWorldQuery
Specifies the ECS data of the item entity required by RenderCommand::render.
The item is the entity that will be rendered for the corresponding view. All components have to be accessed read only.
Required Methods§
fn render<'w>(
item: &P,
view: <<Self::ViewWorldQuery as WorldQuery>::ReadOnly as WorldQuery>::Item<'w>,
entity: <<Self::ItemWorldQuery as WorldQuery>::ReadOnly as WorldQuery>::Item<'w>,
param: <Self::Param as SystemParam>::Item<'w, '_>,
pass: &mut TrackedRenderPass<'w>
) -> RenderCommandResult
fn render<'w>( item: &P, view: <<Self::ViewWorldQuery as WorldQuery>::ReadOnly as WorldQuery>::Item<'w>, entity: <<Self::ItemWorldQuery as WorldQuery>::ReadOnly as WorldQuery>::Item<'w>, param: <Self::Param as SystemParam>::Item<'w, '_>, pass: &mut TrackedRenderPass<'w> ) -> RenderCommandResult
Renders a PhaseItem by recording commands (e.g. setting pipelines, binding bind groups,
issuing draw calls, etc.) via the TrackedRenderPass.