Add Location Component chapter

[spencer-lunarg]

@Tobski @alan-baker - Here is a simple chapter around our favorite topic of Location/Component

1. Please review and make sure we all agree
2. Please suggest other possible "fun" cases to add here for help in future references

(latest commit rendered version - https://github.com/KhronosGroup/Vulkan-Guide/blob/04c334e94c08470961bf4ebfc13520b907acc884/chapters/location_component_interface.adoc)

[Tobski]

Some comments for clarity and a few fixes. I think it would also be a good idea to have a 64-bit example, particularly a 64-bit vec3/4, showing how these consume multiple locations, and how these have to be aligned to even components.

[spencer-lunarg]

I think it would also be a good idea to have a 64-bit example, particularly a 64-bit vec3/4

Here is that example

[alan-baker]

Should this chapter provide guidance on whether the number of locations ought to be minimized? Maybe it should also mention that you can't mix interpolation within a location?

[alan-baker]

Once Vulkan issue 4180 is clarified it would be good to expand this section I think

[spencer-lunarg]

Should this chapter provide guidance on whether the number of locations ought to be minimized? Maybe it should also mention that you can't mix interpolation within a location?

1. Yes, can add a thing at the top explaining the desire to use less if possible (and also there are limit values)
2. I forgot about the interpolation case, will add that

[spencer-lunarg]

@alan-baker for the

that you can't mix interpolation within a location?

Did you mean between two stages? (I plan to have another possible guide about connecting the Location)

As for what I think you mean, it seems that GLSL disallows it, but not spirv-val (https://godbolt.org/z/EohPberKd)

[alan-baker]

@alan-baker for the

that you can't mix interpolation within a location?

Did you mean between two stages? (I plan to have another possible guide about connecting the Location)

As for what I think you mean, it seems that GLSL disallows it, but not spirv-val (https://godbolt.org/z/EohPberKd)

Yes, I know spirv-val doesn't check it. It's good that glslang does, but it's one of those things for new frontends that is sort of a gotcha that's not easy to find.