Trait naga::back::spv::image::Access

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trait Access {
    type Output: MergeTuple + Copy + Clone;

    // Required methods
    fn generate(
        &self,
        id_gen: &mut IdGenerator,
        coordinates_id: Word,
        level_id: Option<Word>,
        sample_id: Option<Word>,
        block: &mut Block,
    ) -> Self::Output;
    fn result_type(&self) -> Self::Output;
    fn out_of_bounds_value(&self, ctx: &mut BlockContext<'_>) -> Self::Output;
}
Expand description

A trait for image access (load or store) code generators.

Types implementing this trait hold information about an ImageStore or ImageLoad operation that is not affected by the bounds check policy. The generate method emits code for the access, given the results of bounds checking.

The image bounds checks policy affects access coordinates, level of detail, and sample index, but never the image id, result type (if any), or the specific SPIR-V instruction used. Types that implement this trait gather together the latter category, so we don’t have to plumb them through the bounds-checking code.

Required Associated Types§

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type Output: MergeTuple + Copy + Clone

The Rust type that represents SPIR-V values and types for this access.

For operations like loads, this is Word. For operations like stores, this is ().

For ReadZeroSkipWrite, this will be the type of the selection construct that performs the bounds checks, so it must implement MergeTuple.

Required Methods§

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fn generate( &self, id_gen: &mut IdGenerator, coordinates_id: Word, level_id: Option<Word>, sample_id: Option<Word>, block: &mut Block, ) -> Self::Output

Write an image access to block.

Access the texel at coordinates_id. The optional level_id indicates the level of detail, and sample_id is the index of the sample to access in a multisampled texel.

This method assumes that coordinates_id has already had the image array index, if any, folded in, as done by write_image_coordinates.

Return the value id produced by the instruction, if any.

Use id_gen to generate SPIR-V ids as necessary.

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fn result_type(&self) -> Self::Output

Return the SPIR-V type of the value produced by the code written by generate. If the access does not produce a value, Self::Output should be ().

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fn out_of_bounds_value(&self, ctx: &mut BlockContext<'_>) -> Self::Output

Construct the SPIR-V ‘zero’ value to be returned for an out-of-bounds access under the ReadZeroSkipWrite policy. If the access does not produce a value, Self::Output should be ().

Implementors§