Struct webrender::texture_cache::TextureCache

pub struct TextureCache {
    shared_textures: SharedTextures,
    max_texture_size: i32,
    tiling_threshold: i32,
    swizzle: Option<SwizzleSettings>,
    debug_flags: DebugFlags,
    pub next_id: CacheTextureId,
    pub pending_updates: TextureUpdateList,
    now: FrameStamp,
    lru_cache: LRUCache<CacheEntry, AutoCacheEntryMarker>,
    manual_entries: FreeList<CacheEntry, ManualCacheEntryMarker>,
    manual_handles: Vec<FreeListHandle<ManualCacheEntryMarker>>,
    bytes_allocated: [usize; 7],
}

General-purpose manager for images in GPU memory. This includes images, rasterized glyphs, rasterized blobs, cached render tasks, etc.

The texture cache is owned and managed by the RenderBackend thread, and produces a series of commands to manipulate the textures on the Renderer thread. These commands are executed before any rendering is performed for a given frame.

Entries in the texture cache are not guaranteed to live past the end of the frame in which they are requested, and may be evicted. The API supports querying whether an entry is still available.

The TextureCache is different from the GpuCache in that the former stores images, whereas the latter stores data and parameters for use in the shaders. This means that the texture cache can be visualized, which is a good way to understand how it works. Enabling gfx.webrender.debug.texture-cache shows a live view of its contents in Firefox.

Fields

shared_textures: SharedTextures

Set of texture arrays in different formats used for the shared cache.

max_texture_size: i32

Maximum texture size supported by hardware.

tiling_threshold: i32

Maximum texture size before it is considered preferable to break the texture into tiles.

swizzle: Option<SwizzleSettings>

Settings on using texture unit swizzling.

debug_flags: DebugFlags

The current set of debug flags.

next_id: CacheTextureId

The next unused virtual texture ID. Monotonically increasing.

pending_updates: TextureUpdateList

A list of allocations and updates that need to be applied to the texture cache in the rendering thread this frame.

now: FrameStamp

The current FrameStamp. Used for cache eviction policies.

lru_cache: LRUCache<CacheEntry, AutoCacheEntryMarker>

Cache of texture cache handles with automatic lifetime management, evicted in a least-recently-used order.

manual_entries: FreeList<CacheEntry, ManualCacheEntryMarker>

Cache of texture cache entries with manual liftime management.

manual_handles: Vec<FreeListHandle<ManualCacheEntryMarker>>

Strong handles for the manual_entries FreeList.

bytes_allocated: [usize; 7]

Memory usage of allocated entries in all of the shared or standalone textures. Includes both manually and automatically evicted entries.

Implementations

impl TextureCache

const MAX_EVICTIONS_PER_FRAME: usize = 32usize

The maximum number of items that will be evicted per frame. This limit helps avoid jank on frames where we want to evict a large number of items. Instead, we’d prefer to drop the items incrementally over a number of frames, even if that means the total allocated size of the cache is above the desired threshold for a small number of frames.

pub fn new( max_texture_size: i32, tiling_threshold: i32, color_formats: TextureFormatPair<ImageFormat>, swizzle: Option<SwizzleSettings>, config: &TextureCacheConfig ) -> Self

pub fn set_debug_flags(&mut self, flags: DebugFlags)

pub fn clear_all(&mut self)

Clear all entries in the texture cache. This is a fairly drastic step that should only be called very rarely.

pub fn begin_frame( &mut self, stamp: FrameStamp, profile: &mut TransactionProfile )

Called at the beginning of each frame.

pub fn end_frame(&mut self, profile: &mut TransactionProfile)

pub fn run_compaction(&mut self, gpu_cache: &mut GpuCache)

pub fn request( &mut self, handle: &TextureCacheHandle, gpu_cache: &mut GpuCache ) -> bool

fn get_entry_opt(&self, handle: &TextureCacheHandle) -> Option<&CacheEntry>

fn get_entry_opt_mut( &mut self, handle: &TextureCacheHandle ) -> Option<&mut CacheEntry>

pub fn needs_upload(&self, handle: &TextureCacheHandle) -> bool

pub fn max_texture_size(&self) -> i32

pub fn tiling_threshold(&self) -> i32

pub fn pending_updates(&mut self) -> TextureUpdateList

pub fn update( &mut self, handle: &mut TextureCacheHandle, descriptor: ImageDescriptor, filter: TextureFilter, data: Option<CachedImageData>, user_data: [f32; 4], dirty_rect: ImageDirtyRect, gpu_cache: &mut GpuCache, eviction_notice: Option<&EvictionNotice>, uv_rect_kind: UvRectKind, eviction: Eviction, shader: TargetShader )

pub fn is_allocated(&self, handle: &TextureCacheHandle) -> bool

pub fn get_allocated_size(&self, handle: &TextureCacheHandle) -> Option<usize>

pub fn get(&self, handle: &TextureCacheHandle) -> CacheItem

pub fn get_cache_location( &self, handle: &TextureCacheHandle ) -> (CacheTextureId, DeviceIntRect, Swizzle, GpuCacheHandle, [f32; 4])

A more detailed version of get(). This allows access to the actual device rect of the cache allocation.

Returns a tuple identifying the texture, the layer, the region, and its GPU handle.

fn evict_impl(&mut self, entry: CacheEntry)

Internal helper function to evict a strong texture cache handle

pub fn evict_handle(&mut self, handle: &TextureCacheHandle)

Evict a texture cache handle that was previously set to be in manual eviction mode.

pub fn dump_color8_linear_as_svg(&self, output: &mut dyn Write) -> Result<()>

pub fn dump_color8_glyphs_as_svg(&self, output: &mut dyn Write) -> Result<()>

pub fn dump_alpha8_glyphs_as_svg(&self, output: &mut dyn Write) -> Result<()>

pub fn dump_alpha8_linear_as_svg(&self, output: &mut dyn Write) -> Result<()>

fn get_eviction_threshold(&self, budget_type: BudgetType) -> usize

Get the eviction threshold, in bytes, for the given budget type.

fn should_continue_evicting( &self, budget_type: BudgetType, eviction_count: usize ) -> Option<u64>

Returns whether to continue eviction and how cold an item need to be to be evicted.

If the None is returned, stop evicting. If the Some(n) is returned, continue evicting if the coldest item hasn’t been used for more than n frames.

fn evict_items_from_cache_if_required( &mut self, profile: &mut TransactionProfile )

Evict old items from the shared and standalone caches, if we’re over a threshold memory usage value

fn free(&mut self, entry: &CacheEntry)

fn allocate_from_shared_cache( &mut self, params: &CacheAllocParams ) -> (CacheEntry, BudgetType)

Allocate a block from the shared cache.

pub fn is_allowed_in_shared_cache( &self, filter: TextureFilter, descriptor: &ImageDescriptor ) -> bool

pub fn alloc_render_target( &mut self, size: DeviceIntSize, format: ImageFormat ) -> CacheTextureId

Allocate a render target via the pending updates sent to the renderer

pub fn free_render_target(&mut self, id: CacheTextureId)

Free an existing render target

fn allocate_standalone_entry( &mut self, params: &CacheAllocParams ) -> (CacheEntry, BudgetType)

Allocates a new standalone cache entry.

fn allocate( &mut self, params: &CacheAllocParams, handle: &mut TextureCacheHandle, eviction: Eviction )

Allocates a cache entry for the given parameters, and updates the provided handle to point to the new entry.

pub fn shared_alpha_expected_format(&self) -> ImageFormat

pub fn shared_color_expected_format(&self) -> ImageFormat

pub fn report_memory(&self, ops: &mut MallocSizeOfOps) -> usize

Trait Implementations

impl Serialize for TextureCache

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>where __S: Serializer,

Serialize this value into the given Serde serializer.