关于HLSL语义的问题

Question

我想定义这样的顶点结构：

struct VertexIn
{
float3 PosL    : POSITION;
float3 NormalL : NORMAL;
float2 TexC    : TEXCOORD;
float SH[9]; // ?
};

如何选择"SH"数组的顶点语义？我可以自己定义语义吗？

然后我尝试了这个：

// in hlsl:
struct VertexIn
{
float3 PosL    : POSITION;
float3 NormalL : NORMAL;
float2 TexC    : TEXCOORD;
float SH[9] : SHCOEFFICIENT; // ???
};
// cpp:
mInputLayout =
{
{ "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
{ "NORMAL", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 12, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
{ "TEXCOORD", 0, DXGI_FORMAT_R32G32_FLOAT, 0, 24, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
{ "SHCOEFFICIENT", 0, DXGI_FORMAT_R32_FLOAT, 0, 32, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0}, // ???
};

当然，这是错误的。所以我暂时将数组拆分为9个元素，但看起来很愚蠢。

Answer 1

您可以使用SemanticIndex参数。你可以定义你的输入布局

mInputLayout =
{
{ "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
{ "NORMAL", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 12, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
{ "TEXCOORD", 0, DXGI_FORMAT_R32G32_FLOAT, 0, 24, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
{ "SHCOEFFICIENT", 0, DXGI_FORMAT_R32_FLOAT, 0, 32, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0},
{ "SHCOEFFICIENT", 1, DXGI_FORMAT_R32_FLOAT, 0, 36, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0},
{ "SHCOEFFICIENT", 2, DXGI_FORMAT_R32_FLOAT, 0, 40, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0},
...
{ "SHCOEFFICIENT", 8, DXGI_FORMAT_R32_FLOAT, 0, 64, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0}
};

或者像这样：

mInputLayout =
{
{ "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
{ "NORMAL", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 12, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
{ "TEXCOORD", 0, DXGI_FORMAT_R32G32_FLOAT, 0, 24, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
{ "SHCOEFFICIENT", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 32, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0},
{ "SHCOEFFICIENT", 1, DXGI_FORMAT_R32G32B32_FLOAT, 0, 44, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0},
{ "SHCOEFFICIENT", 2, DXGI_FORMAT_R32G32B32_FLOAT, 0, 56, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0},
};

但是更改你的顶点

struct VertexIn
{
float3 PosL    : POSITION;
float3 NormalL : NORMAL;
float2 TexC    : TEXCOORD;
float3 SH[3]   : SHCOEFFICIENT; 
};