Struct MTKMesh

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#[repr(C)]
pub struct MTKMesh { /* private fields */ }

Available on crate feature MTKModel only.

Expand description

Container for vertex data of a mesh and submeshes to render it.

Implementations§

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impl MTKMesh

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pub unsafe fn init(this: Allocated<Self>) -> Retained<Self>

Cannot use default init. Must initialize with mesh and metal device.

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pub unsafe fn initWithMesh_device_error( this: Allocated<Self>, mesh: &MDLMesh, device: &ProtocolObject<dyn MTLDevice>, ) -> Result<Retained<Self>, Retained<NSError>>

Available on crate feature objc2-model-io only.

Initialize the mesh and the mesh’s submeshes.

Parameter mesh: Model I/O Mesh from which to create this MetalKit mesh

Parameter device: Metal device on which to create mesh resources

Parameter error: Pointer to an NSError object set if an error occurred

The designated initializer for this class. This does NOT initialize any meshes that are children of the Model I/O mesh, only submeshes that are part of the given mesh. An exception is raised if vertexBuffer objects in the given mesh and the indexBuffer of any submesh in this mesh have not been created with a MTKMeshBufferAllocator object. If a submesh using MDLGeometryTypeQuads or MDLGeometryTypeTopology is used, that submesh will be copied, and recreated to use MDLGeometryTypeTriangles, before this routine creates the MTKSubmesh.

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pub unsafe fn newMeshesFromAsset_device_sourceMeshes_error( asset: &MDLAsset, device: &ProtocolObject<dyn MTLDevice>, source_meshes: Option<&mut Option<Retained<NSArray<MDLMesh>>>>, ) -> Result<Retained<NSArray<MTKMesh>>, Retained<NSError>>

Available on crate feature objc2-model-io only.

Initialize all meshes in a Model I/O asset.

Parameter asset: Model I/O asset from which to create MetalKit meshes

Parameter device: Metal device on which to create mesh resources

Parameter sourceMeshes: Array built by this method containing MDLMesh objects corresponding the returned MTKMesh objects

Parameter error: Pointer to an NSError object set if an error occurred

Returns: MetalKit Meshes created from the Model I/O asset

A convenience method to create MetalKit meshes from each mesh in a Model I/O asset. resulting meshes are returned while the corresponding Model I/O meshes from which they were generated will appear in the sourceMeshes array. All vertexBuffer objects in each MDLMesh object in the asset and the indexBuffer of each submesh within each of these meshes must have been created using a MTKMeshBufferAllocator object. Thus

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pub unsafe fn vertexBuffers(&self) -> Retained<NSArray<MTKMeshBuffer>>

Array of buffers in which mesh vertex data resides.

This is filled with mesh buffer objects using the layout described by the vertexDescriptor property. Elements in this array can be [NSNull null] if the vertexDescriptor does not specify elements for buffer for the given index

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pub unsafe fn vertexDescriptor(&self) -> Retained<MDLVertexDescriptor>

Available on crate feature objc2-model-io only.

Model I/O vertex descriptor specifying the layout of data in vertexBuffers.

This is not directly used by this object, but the application can use this information to determine rendering state or create a Metal vertex descriptor to build a RenderPipelineState object capable of interpreting data in ‘vertexBuffers’. Changing propties in the object will not result in the relayout data in vertex descriptor and thus will make the vertex descriptor no loger describe the layout of vertes data and verticies. (i.e. don’t change properties in this vertexDescriptor)

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pub unsafe fn submeshes(&self) -> Retained<NSArray<MTKSubmesh>>

Submeshes containing index buffers to rendering mesh vertices.

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pub unsafe fn vertexCount(&self) -> NSUInteger

Number of vertices in the vertexBuffers.

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pub unsafe fn name(&self) -> Retained<NSString>

Name of the mesh copies from the originating Model I/O mesh.

Can be used by the app to identify the mesh in its scene/world/renderer etc.

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pub unsafe fn setName(&self, name: &NSString)

Setter for name.

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impl MTKMesh

Methods declared on superclass NSObject.

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pub unsafe fn new() -> Retained<Self>

Methods from Deref<Target = NSObject>§

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pub fn doesNotRecognizeSelector(&self, sel: Sel) -> !

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>§

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pub fn class(&self) -> &'static AnyClass

Dynamically find the class of this object.

§Example

Check that an instance of NSObject has the precise class NSObject.

use objc2::ClassType;
use objc2::runtime::NSObject;

let obj = NSObject::new();
assert_eq!(obj.class(), NSObject::class());

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pub unsafe fn get_ivar<T>(&self, name: &str) -> &T
where T: Encode,

👎Deprecated: this is difficult to use correctly, use Ivar::load instead.

Use Ivar::load instead.

§Safety

The object must have an instance variable with the given name, and it must be of type T.

See Ivar::load_ptr for details surrounding this.

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

Attempt to downcast the object to a class of type T.

This is the reference-variant. Use Retained::downcast if you want to convert a retained object to another type.

§Mutable classes

Some classes have immutable and mutable variants, such as NSString and NSMutableString.

When some Objective-C API signature says it gives you an immutable class, it generally expects you to not mutate that, even though it may technically be mutable “under the hood”.

So using this method to convert a NSString to a NSMutableString, while not unsound, is generally frowned upon unless you created the string yourself, or the API explicitly documents the string to be mutable.

See Apple’s documentation on mutability and on isKindOfClass: for more details.

§Generic classes

Objective-C generics are called “lightweight generics”, and that’s because they aren’t exposed in the runtime. This makes it impossible to safely downcast to generic collections, so this is disallowed by this method.

You can, however, safely downcast to generic collections where all the type-parameters are AnyObject.

§Panics

This works internally by calling isKindOfClass:. That means that the object must have the instance method of that name, and an exception will be thrown (if CoreFoundation is linked) or the process will abort if that is not the case. In the vast majority of cases, you don’t need to worry about this, since both root objects NSObject and NSProxy implement this method.

§Examples

Cast an NSString back and forth from NSObject.

use objc2::rc::Retained;
use objc2_foundation::{NSObject, NSString};

let obj: Retained<NSObject> = NSString::new().into_super();
let string = obj.downcast_ref::<NSString>().unwrap();
// Or with `downcast`, if we do not need the object afterwards
let string = obj.downcast::<NSString>().unwrap();

Try (and fail) to cast an NSObject to an NSString.

use objc2_foundation::{NSObject, NSString};

let obj = NSObject::new();
assert!(obj.downcast_ref::<NSString>().is_none());

Try to cast to an array of strings.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);
// This is invalid and doesn't type check.
let arr = arr.downcast_ref::<NSArray<NSString>>();

This fails to compile, since it would require enumerating over the array to ensure that each element is of the desired type, which is a performance pitfall.

Downcast when processing each element instead.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);

for elem in arr {
    if let Some(data) = elem.downcast_ref::<NSString>() {
        // handle `data`
    }
}