Struct CVMetalTextureCache

Source

pub struct CVMetalTextureCache { /* private fields */ }

Available on crate feature CVMetalTextureCache only.

Expand description

CoreVideo Metal Texture Cache

Implementations§

Source §

impl CVMetalTextureCache

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pub unsafe fn create( allocator: Option<&CFAllocator>, cache_attributes: Option<&CFDictionary>, metal_device: &ProtocolObject<dyn MTLDevice>, texture_attributes: Option<&CFDictionary>, cache_out: NonNull<*mut CVMetalTextureCache>, ) -> CVReturn

Available on crate feature CVReturn and crate feature objc2 and crate feature objc2-metal and non-watchOS only.

Creates a new Texture Cache.

Parameter allocator: The CFAllocatorRef to use for allocating the cache. May be NULL.

Parameter cacheAttributes: A CFDictionaryRef containing the attributes of the cache itself. May be NULL.

Parameter metalDevice: The Metal device for which the texture objects will be created.

Parameter textureAttributes: A CFDictionaryRef containing the attributes to be used for creating the CVMetalTexture objects. May be NULL.

Parameter cacheOut: The newly created texture cache will be placed here

Returns: Returns kCVReturnSuccess on success

§Safety

cache_attributes generics must be of the correct type.
texture_attributes generics must be of the correct type.
cache_out must be a valid pointer.

Source

pub unsafe fn create_texture_from_image( allocator: Option<&CFAllocator>, texture_cache: &CVMetalTextureCache, source_image: &CVImageBuffer, texture_attributes: Option<&CFDictionary>, pixel_format: MTLPixelFormat, width: usize, height: usize, plane_index: usize, texture_out: NonNull<*mut CVMetalTexture>, ) -> CVReturn

Available on crate feature CVBuffer and crate feature CVImageBuffer and crate feature CVMetalTexture and crate feature CVReturn and crate feature objc2-metal and non-watchOS only.

Creates a CVMetalTexture object from an existing CVImageBuffer

Parameter allocator: The CFAllocatorRef to use for allocating the CVMetalTexture object. May be NULL.

Parameter textureCache: The texture cache object that will manage the texture.

Parameter sourceImage: The CVImageBuffer that you want to create a CVMetalTexture from.

Parameter textureAttributes: A CFDictionaryRef containing attributes to be used for creating the CVMetalTexture objects. May be NULL.

Parameter pixelFormat: Specifies the Metal pixel format.

Parameter width: Specifies the width of the texture image.

Parameter height: Specifies the height of the texture image.

Parameter planeIndex: Specifies the plane of the CVImageBuffer to map bind. Ignored for non-planar CVImageBuffers.

Parameter textureOut: The newly created texture object will be placed here.

Returns: Returns kCVReturnSuccess on success

Creates or returns a cached CVMetalTexture texture object mapped to the CVImageBuffer and associated params. This creates a live binding between the CVImageBuffer and underlying CVMetalTexture texture object.

IMPORTANT NOTE: Clients should retain CVMetalTexture objects until they are done using the images in them. Retaining a CVMetalTexture is your way to indicate that you’re still using the image in the buffer, and that it should not be recycled yet.

Note that CoreVideo does not explicitly declare any pixel format types to be Metal compatible. The assumption is that if the CVPixelBufferMetalCompatibilityKey has been specified, all buffers will be Metal compatible (IOSurface backed), and thus it is the developer’s responsibility to choose an appropriate Metal pixel format for the CVPixelBuffers.

Here are some example mappings:

Mapping a BGRA buffer: CVMetalTextureCacheCreateTextureFromImage(kCFAllocatorDefault, textureCache, pixelBuffer, NULL, MTLPixelFormatBGRA8Unorm, width, height, 0, &outTexture );

Mapping the luma plane of a 420v buffer: CVMetalTextureCacheCreateTextureFromImage(kCFAllocatorDefault, textureCache, pixelBuffer, NULL, MTLPixelFormatR8Unorm, width, height, 0, &outTexture );

Mapping the chroma plane of a 420v buffer as a source texture: CVMetalTextureCacheCreateTextureFromImage(kCFAllocatorDefault, textureCache, pixelBuffer, NULL, MTLPixelFormatRG8Unorm width/2, height/2, 1, &outTexture );

Mapping a yuvs buffer as a source texture (note: yuvs/f and 2vuy are unpacked and resampled – not colorspace converted) CVMetalTextureCacheCreateTextureFromImage(kCFAllocatorDefault, textureCache, pixelBuffer, NULL, MTLPixelFormatGBGR422, width, height, 1, &outTexture );

§Safety

texture_attributes generics must be of the correct type.
texture_out must be a valid pointer.

Source

pub fn flush(&self, options: CVOptionFlags)

Available on crate feature CVBase only.

Performs internal housekeeping/recycling operations

This call must be made periodically to give the texture cache a chance to do internal housekeeping operations.

Parameter textureCache: The texture cache object to flush

Parameter options: Currently unused, set to 0.

Methods from Deref<Target = CFType>§

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pub fn downcast_ref<T>(&self) -> Option<&T>
where T: ConcreteType,

Attempt to downcast the type to that of type T.

This is the reference-variant. Use CFRetained::downcast if you want to convert a retained type. See also ConcreteType for more details on which types support being converted to.

Source

pub fn retain_count(&self) -> usize

Get the reference count of the object.

This function may be useful for debugging. You normally do not use this function otherwise.

Beware that some things (like CFNumbers, small CFStrings etc.) may not have a normal retain count for optimization purposes, and can return usize::MAX in that case.