Update Location Chapter for matrix #321
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Tobski
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Jun 26, 2025
Tobski
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Pending resolution of the internal MR but this is a necessary update if/when that lands.
| A matrix is viewed as an array, which consume all 4 components. | ||
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| So something like | ||
| A matrix is viewed as an array of vector, this means something like |
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| A matrix is viewed as an array of vector, this means something like | |
| A matrix is stored as an array of vector, this means something like |
"Viewed as" implies something else.
| ---- | ||
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| From a `Location`/`Component` point-of-view looks like | ||
| from a `Location`/`Component` point-of-view looks like |
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| from a `Location`/`Component` point-of-view looks like | |
| consumes locations and components identically to |
| ---- | ||
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| As stated above, arrays consume the whole `Location` so the following is **not** allowed. | ||
| Just like vector, depending on the size, it may not consume the whole `Location`. This means the following is allowed. |
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| Just like vector, depending on the size, it may not consume the whole `Location`. This means the following is allowed. | |
| which in turn is stored identically to | |
| [source,glsl] | |
| ---- | |
| // Each vector consumes only the first 2 components of each location | |
| layout(location = 0) vec2 a0; | |
| layout(location = 1) vec2 a1; | |
| layout(location = 2) vec2 a2; | |
| ---- | |
| This means the following is allowed: |
Also the "Arrays consume whole location" comment above is wrong - where did that come from?
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| You don't need to worry about things going "in front" of a matrix because the `Component` decoration | ||
| link:https://godbolt.org/z/f81PvP538[can not be applied on a matrix type]. |
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| You don't need to worry about things going "in front" of a matrix because the `Component` decoration | |
| link:https://godbolt.org/z/f81PvP538[can not be applied on a matrix type]. | |
| Unlike arrays or independent vectors, link:https://godbolt.org/z/f81PvP538[matrices cannot be decorated with `Component`], so will always be packed from component 0. |
Maybe? "In front" seems overly vague to me.
Contributor
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Hi @spencer-lunarg, anything you need to get this ready to merge? Thx |
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this is still pending spec clarification which is pending CTS... so might be open for a bit long |
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More updates from https://gitlab.khronos.org/vulkan/vulkan/-/merge_requests/7455
cc @alan-baker @Tobski hopefully this is the final chapter of the Location saga