Struct MTL4PrimitiveAccelerationStructureDescriptor

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pub struct MTL4PrimitiveAccelerationStructureDescriptor { /* private fields */ }

Available on crate features MTL4AccelerationStructure and MTLAccelerationStructure only.

Expand description

Descriptor for a primitive acceleration structure that directly references geometric shapes, such as triangles and bounding boxes.

Implementations§

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impl MTL4PrimitiveAccelerationStructureDescriptor

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pub fn geometryDescriptors( &self, ) -> Option<Retained<NSArray<MTL4AccelerationStructureGeometryDescriptor>>>

Associates the array of geometry descriptors that comprise this primitive acceleration structure.

If you enable keyframe motion by setting property motionKeyframeCount to a value greater than 1, then all geometry descriptors this array references need to be motion geometry descriptors and have a number of primitive buffers equals to motionKeyframeCount.

Example of motion geometry descriptors include: MTL4AccelerationStructureMotionTriangleGeometryDescriptor, MTL4AccelerationStructureMotionBoundingBoxGeometryDescriptor, MTL4AccelerationStructureMotionCurveGeometryDescriptor.

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pub fn setGeometryDescriptors( &self, geometry_descriptors: Option<&NSArray<MTL4AccelerationStructureGeometryDescriptor>>, )

Setter for geometryDescriptors.

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pub fn motionStartBorderMode(&self) -> MTLMotionBorderMode

Configures the behavior when the ray-tracing system samples the acceleration structure before the motion start time.

Use this property to control the behavior when the ray-tracing system samples the acceleration structure at a time prior to the one you set for motionStartTime.

The default value of this property is MTLMotionBorderModeClamp.

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pub fn setMotionStartBorderMode( &self, motion_start_border_mode: MTLMotionBorderMode, )

Setter for motionStartBorderMode.

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pub fn motionEndBorderMode(&self) -> MTLMotionBorderMode

Configures the motion border mode.

This property controls what happens if Metal samples the acceleration structure after motionEndTime.

Its default value is MTLMotionBorderModeClamp.

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pub fn setMotionEndBorderMode( &self, motion_end_border_mode: MTLMotionBorderMode, )

Setter for motionEndBorderMode.

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pub fn motionStartTime(&self) -> c_float

Configures the motion start time for this geometry.

The default value of this property is 0.0f.

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pub fn setMotionStartTime(&self, motion_start_time: c_float)

Setter for motionStartTime.

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pub fn motionEndTime(&self) -> c_float

Configures the motion end time for this geometry.

The default value of this property is 1.0f.

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pub fn setMotionEndTime(&self, motion_end_time: c_float)

Setter for motionEndTime.

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pub fn motionKeyframeCount(&self) -> NSUInteger

Sets the motion keyframe count.

This property’s default is 1, indicating no motion.

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pub unsafe fn setMotionKeyframeCount(&self, motion_keyframe_count: NSUInteger)

Setter for motionKeyframeCount.

§Safety

This might not be bounds-checked.

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impl MTL4PrimitiveAccelerationStructureDescriptor

Methods declared on superclass NSObject.

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

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pub fn new() -> Retained<Self>

Methods from Deref<Target = MTLAccelerationStructureDescriptor>§

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pub fn usage(&self) -> MTLAccelerationStructureUsage

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pub fn setUsage(&self, usage: MTLAccelerationStructureUsage)

Setter for usage.

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.

§Panics

May panic if the object is invalid (which may be the case for objects returned from unavailable init/new methods).

§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`
    }
}