Fix imageStore output for types other than 4-vectors (#622)

Fixes issue #620

Given a `RWTexture*` store operation like:

```hlsl
RWTexture3D a<float>;
...
float x = 1.0f;
a[crd] = x;
```

We were generating output GLSL like:

```glsl
layout(rgba32f) image3D a;
...
float x = 1.0f;
imageStore(a, crd, x);
```

but in that case, the `imageStore` operation expected a `vec4` and not a `float` for the last argument, and we fail GLSL compilation.

This change extends our handling of the `imageStore` operation in the stdlib so that we pad out the last argument if it is not a 4-vector.

We also flesh out the code that was picking a `layout(...)` modifier for image formats so that it doesn't just blindly use `layout(rgba32f)` and instead takes the element type fed to `RWTexture3D<...>` into account.

With these two changes, the above HLSL/Slang code now translates to:

```glsl
layout(r32f) image3D a;
...
float x = 1.0f;
imageStore(a, crd, vec4(x, float(0), float(0), float(0)));
```

Note that we are padding out the `x` argument to a full vector, and also that we declare the image with `layout(r32f)` to reflect the fact that it has only as single channel.

0 files changed, 0 insertions, 0 deletions