Update 1-1-3-hello-triangle.md for #95 #124
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github actions is still broken due to perms |
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yes I already fixed it with b7ad37b, but on PRs it seems to use the old workflows, even when I click 'Re-run jobs' and doesn't update them directly. Perhaps push a empty commit and see if it re-runs properly? |
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Consider testing those workflow things using your fork before committing nonsense to the repo, thanks :) |
16-Bit-Dog
changed the title
| - `SemanticName`: lets us refer to a particular field given the string after the colon in HLSL (remember `float3 position: POSITION`) | ||
| D3D11_INPUT_ELEMENT_DESC vertexInputLayoutInfo[] is an array since when we pass data to a GPU to read in the **vertex shader** we need to specify to the GPU how 1 vertex of data will be formatted for when we later load many vertices onto the GPU to render a triangle. | ||
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| **now lets explain what makes up a Input Layout Description** |
| this allows us to do things such as have 4 elements named `POSITION`, with a semantic index of 0, 1, 2, 3 — being convenient for the programmer to not have to type `POSITION0` `POSITION1` `POSITION2` `POSITION3` | ||
| - `Format`: the format of this field, basically how many components there are and what type they are, a `float3` in HLSL is a vector of 3 floats, each float is 4 bytes wide (or 32 bits), so the format here is `DXGI_FORMAT_R32G32B32_FLOAT`. We made a `float3` to map to `VSInput` and the types inside the HLSL struct | ||
| - `InputSlot`: we'll see about this later since right now it has no use, but for now all you need to know is that a GPU cannot store an infinite amount of Input Layouts, instead you specify here what 'slot' this input layout occupy's in memory that stores input layouts. | ||
| - `AlignedByteOffset`: the offset of where this field starts in the memory of 1 vertex in bytes. For example with `vertexInputLayoutInfo`, since we want `COLOR` after `POSITION` which is a `float3` (12 bytes) — we tell D3D11 that we want a 12 byte offset to put `COLOR` immediately after `POSITION` in memory. `POSITION` on the other hand needs no offset and is the first element (offset is 0). |
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Maybe this could be remassaged into explaining offsetof here instead of adding those comments up in the code (which i dont like that much)
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I am fine to make this change - I think it may have a small negative to reader since more obfuscated data, but probably not important in the grand scheme of things
it needed a rewording anyways
| - `InputSlot`: we'll see about this later since right now it has no use, but for now all you need to know is that a GPU cannot store an infinite amount of Input Layouts, instead you specify here what 'slot' this input layout occupy's in memory that stores input layouts. | ||
| - `AlignedByteOffset`: the offset of where this field starts in the memory of 1 vertex in bytes. For example with `vertexInputLayoutInfo`, since we want `COLOR` after `POSITION` which is a `float3` (12 bytes) — we tell D3D11 that we want a 12 byte offset to put `COLOR` immediately after `POSITION` in memory. `POSITION` on the other hand needs no offset and is the first element (offset is 0). | ||
| offsetof(VertexPositionColor, color) is a preprocessor that calcualtes the offset for us using a struct and its element name as input | ||
| - `InputSlotClass`: The rate of input is either per-vertex or per-instance, we don't care about instances right now, so we'll set this to PER_VERTEX. |
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maybe instead of "we dont care about x" we should write "you can ignore x for now, we will pick it up later when we use it"??? not sure
| UINT InstanceDataStepRate | ||
| } | ||
| ``` | ||
| - `SemanticName`: Tells the GPU to expect in the **vertex shader** that a variable in a vertex shader input struct (`VSInput` in this case) with the same `SemanticName` (string after a colon in the vertex shader's declaration — recall `float3 position: STUFF_AFTER_COLON`) will be where the GPU puts the received data. |
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This sentence is quite long and too many stuff is wrapped in braces somehow :) can this maybe broken into 2 or more sentences and dont be afraid to write more text if you have to.
the last (string after a colon ... feels kinda strange the way its written, but it could also just be me
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I agree, I adjusted it and will make a more natural language setup to explain the process.
I start with what it is, how it links - and then simply a part of where it actually is shown in the gpu code, but revised the English to be better
| DXGI_FORMAT::DXGI_FORMAT_R32G32B32_FLOAT, | ||
| 0, | ||
| offsetof(VertexPositionColor, position), | ||
| offsetof(VertexPositionColor, position) /*resolves to 0*/, |
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please remove the comments from offsetof as mentioned below
docs/1-introduction/1-1-getting-started/1-1-3-hello-triangle.md
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