Matrix alignment mismatch with push constants

[chlobes]

• Version of vulkano: 0.12.0 and 0.11.1
• OS: Arch Linux
• GPU: Geforce GTX 1050 Ti
• GPU Driver: "NVIDIA Unified Driver for all Supported NVIDIA GPUs"

#version 450
//fragment shader

layout(push_constant) uniform PushConstants {
    mat3 m;
} pc;

out layout(location = 0) out vec4 target;

void main() {
    target = pc.m * vec3(0.0, 1.0, 1.0);
    //results in a black screen when identity matrix is used, because the identity matrix is instead read as [[1, 0, 0], [1, 0, 0], [1, 0, 0]]
}

Issue

Rust packs the matrix too tightly, as an [[f32; 3]; 3], with no gaps between elements, whereas the gpu expects an [[f32; 4]; 3], where the last element of each [f32; 4] is dummy data.
This means that the gpu will read m[1] as [m[1][1], m[1][2], m[2][0]] and m[2] as [m[2][2], m[3][0], m[3][1]] (out of bounds array accesses, potential UB as well as being incorrect?), m[0] will be read normally.

[Azorlogh]

I can confirm this on my machine, I just encountered this problem :
Version of vulkano: 0.13.0 & 0.16.0
OS: Windows 10 x64
GPU: Geforce GT 650M

[LeonMatthes]

Hi, I'm also experiencing this issue at the moment with vulkano 0.29

[marc0246]

This has been fixed in #2132.