Nalgebra vector fails to be recongized
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Description
I tried using nalgebra (no-std) for types in shaders, but the simplest shaders fails to compile.
use nalgebra::Vector4;
use spirv_std::spirv;
#[allow(dead_code)]
#[spirv(fragment)]
pub fn main_fs(output: &mut Vector4<f32>) {
*output = Vector4::new(1.0, 0.0, 0.0, 1.0);
}
#[allow(dead_code)]
#[spirv(vertex)]
pub fn main_vs(
#[spirv(vertex_index)] vert_id: i32,
#[spirv(position, invariant)] out_pos: &mut Vector4<f32>,
) {
*out_pos = Vector4::new(
(vert_id - 1) as f32,
((vert_id & 1) * 2 - 1) as f32,
0.0,
1.0,
);
}
Is the module I am trying to compile, and the error received is:
error: [VUID-Position-Position-04321] According to the Vulkan spec BuiltIn Position variable needs to be a 4-component 32-bit float vector. ID <3> (OpVariable) is not a float vector.
|
= note: module `/home/marios/proj/hestia_vk/target/spirv-builder/spirv-unknown-vulkan1.2/release/deps/shaders.spvs/mesh-main_vs.spv`
warning: an unknown error occurred
|
= note: spirv-opt failed, leaving as unoptimized
= note: module `/home/marios/proj/hestia_vk/target/spirv-builder/spirv-unknown-vulkan1.2/release/deps/shaders.spvs/mesh-main_vs.spv`
error: error:0:0 - [VUID-Position-Position-04321] According to the Vulkan spec BuiltIn Position variable needs to be a 4-component 32-bit float vector. ID <3> (OpVariable) is not a float vector.
%50 = OpInBoundsAccessChain %_ptr_Output__arr_float_uint_4 %out_pos %uint_0 %uint_0 %uint_0
|
= note: spirv-val failed
If I comment out the main_vs function all is well.
It seems like the Vector4 type isnt being interpreted as a [f32;4]
I am wondering if this is because of the underlying type: pub struct ArrayStorage<T, const R: usize, const C: usize>(pub [[T; R]; C]);
It evaluates with R=4, C=1, making the inner type [[f32; 4],1]
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the minimal shader entry points main_vs and main_fs and reproduce the Vulkan validation failure using nalgebra::Vector4. Inspect the generated mesh-main_vs.spv and its Position variable to determine whether the vector representation is emitted correctly; done means the shader validates with main_vs enabled.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- compilers, computer-graphics
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100