Trait webrender::render_target::RenderTarget

pub trait RenderTarget {
    // Required methods
    fn new(
        texture_id: CacheTextureId,
        screen_size: DeviceIntSize,
        gpu_supports_fast_clears: bool,
        used_rect: DeviceIntRect,
    ) -> Self;
    fn add_task(
        &mut self,
        task_id: RenderTaskId,
        ctx: &RenderTargetContext<'_, '_>,
        gpu_cache: &mut GpuCache,
        gpu_buffer_builder: &mut GpuBufferBuilder,
        render_tasks: &RenderTaskGraph,
        clip_store: &ClipStore,
        transforms: &mut TransformPalette,
    );
    fn needs_depth(&self) -> bool;
    fn texture_id(&self) -> CacheTextureId;

    // Provided method
    fn build(
        &mut self,
        _ctx: &mut RenderTargetContext<'_, '_>,
        _gpu_cache: &mut GpuCache,
        _render_tasks: &RenderTaskGraph,
        _prim_headers: &mut PrimitiveHeaders,
        _transforms: &mut TransformPalette,
        _z_generator: &mut ZBufferIdGenerator,
        _prim_instances: &[PrimitiveInstance],
        _cmd_buffers: &CommandBufferList,
        _gpu_buffer_builder: &mut GpuBufferBuilder,
    ) { ... }
}

Represents a number of rendering operations on a surface.

In graphics parlance, a “render target” usually means “a surface (texture or framebuffer) bound to the output of a shader”. This trait has a slightly different meaning, in that it represents the operations on that surface before it’s actually bound and rendered. So a RenderTarget is built by the RenderBackend by inserting tasks, and then shipped over to the Renderer where a device surface is resolved and the tasks are transformed into draw commands on that surface.

We express this as a trait to generalize over color and alpha surfaces. a given RenderTask will draw to one or the other, depending on its type and sometimes on its parameters. See RenderTask::target_kind.

Required Methods

fn new( texture_id: CacheTextureId, screen_size: DeviceIntSize, gpu_supports_fast_clears: bool, used_rect: DeviceIntRect, ) -> Self

Creates a new RenderTarget of the given type.

fn add_task( &mut self, task_id: RenderTaskId, ctx: &RenderTargetContext<'_, '_>, gpu_cache: &mut GpuCache, gpu_buffer_builder: &mut GpuBufferBuilder, render_tasks: &RenderTaskGraph, clip_store: &ClipStore, transforms: &mut TransformPalette, )

Associates a RenderTask with this target. That task must be assigned to a region returned by invoking allocate() on this target.

TODO(gw): It’s a bit odd that we need the deferred resolves and mutable GPU cache here. They are typically used by the build step above. They are used for the blit jobs to allow resolve_image to be called. It’s a bit of extra overhead to store the image key here and the resolve them in the build step separately. BUT: if/when we add more texture cache target jobs, we might want to tidy this up.

fn needs_depth(&self) -> bool

fn texture_id(&self) -> CacheTextureId

Provided Methods

fn build( &mut self, _ctx: &mut RenderTargetContext<'_, '_>, _gpu_cache: &mut GpuCache, _render_tasks: &RenderTaskGraph, _prim_headers: &mut PrimitiveHeaders, _transforms: &mut TransformPalette, _z_generator: &mut ZBufferIdGenerator, _prim_instances: &[PrimitiveInstance], _cmd_buffers: &CommandBufferList, _gpu_buffer_builder: &mut GpuBufferBuilder, )

Optional hook to provide additional processing for the target at the end of the build phase.

Object Safety

This trait is not object safe.

Implementors

impl RenderTarget for AlphaRenderTarget

impl RenderTarget for ColorRenderTarget