triangles.maxVertex seems to get a wrong value

[shiuang]

In

vk_mini_path_tracer/vk_mini_path_tracer/main.cpp

Line 143 in 6095e1d

triangles.maxVertex = static_cast<uint32_t>(objVertices.size() - 1);

objVertices.size() - 1 is assigned to triangles.maxVertex. Since objVertices is a vector of floats instead of a vector of vertices, the size of objVertices indicates total number of floats (3x number of vertices).

In Vulkan specs

maxVertex is the highest index of a vertex that will be addressed by a build command using this structure.

So objVertices.size() / 3 - 1 should be the correct value if I got it right.

BTW, it is also confusing that Vulkan uses highest index of a vertex instead of number of vertices, while the DirectX API uses VertexCount in D3D12_RAYTRACING_GEOMETRY_TRIANGLES_DESC struct. Does anyone know why?

[NBickford-NV]

Hi shiuang! I think you're correct - I've fixed this upstream, and this should be included in the next nvpro-samples bulk update (I'll close the issue then). I don't know about the VertexCount difference, unfortunately!

[shiuang]

Thank you for your reply, NeilBickford-NV.

[NBickford-NV]

Alright, this has been fixed in commit 5cf2ea9 - thanks again!