Struct wgpu::TlasInstance

pub struct TlasInstance {
    pub transform: [f32; 12],
    pub custom_index: u32,
    pub mask: u8,
    /* private fields */
}

Safe instance for a Tlas.

A TlasInstance may be made invalid, if a TlasInstance is invalid, any attempt to build a TlasPackage containing an invalid TlasInstance will generate a validation error

Each one contains:

• A reference to a BLAS, this must be interacted with using TlasInstance::new or TlasInstance::set_blas, a TlasInstance that references a BLAS keeps that BLAS from being dropped, but if the BLAS is explicitly destroyed (e.g. using Blas::destroy) the TlasInstance becomes invalid
• A user accessible transformation matrix
• A user accessible mask
• A user accessible custom index

Fields

transform: [f32; 12]

Affine transform matrix 3x4 (rows x columns, row major order).

custom_index: u32

Custom index for the instance used inside the shader.

This must only use the lower 24 bits, if any bits are outside that range (byte 4 does not equal 0) the TlasInstance becomes invalid and generates a validation error when built

mask: u8

Mask for the instance used inside the shader to filter instances. Reports hit only if (shader_cull_mask & tlas_instance.mask) != 0u.

Implementations

impl TlasInstance

pub fn new( blas: &Blas, transform: [f32; 12], custom_index: u32, mask: u8 ) -> Self

Construct TlasInstance.

• blas: Reference to the bottom level acceleration structure
• transform: Transform buffer offset in bytes (optional, required if transform buffer is present)
• custom_index: Custom index for the instance used inside the shader (max 24 bits)
• mask: Mask for the instance used inside the shader to filter instances

Note: while one of these contains a reference to a BLAS that BLAS will not be dropped, but it can still be destroyed. Destroying a BLAS that is referenced by one or more TlasInstance(s) will immediately make them invalid. If one or more of those invalid TlasInstances is inside a TlasPackage that is attempted to be built, the build will generate a validation error.

pub fn set_blas(&mut self, blas: &Blas)

Set the bottom level acceleration structure.

See the note on TlasInstance about the guarantees of keeping a BLAS alive.

Trait Implementations

impl Clone for TlasInstance

fn clone(&self) -> TlasInstance

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TlasInstance

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.