HLSL written SV_VertexID works different in opengl after automatic compile

Unity Engine
1

Shader is different from directx. I used hlsl in shader. I think unity converts it wrong.

2

If you think shader compilation is incorrect, please submit a bug report.

3

Allright, I’ll upload it today.

1 Like
4

@aleksandrk I have uploaded it but forgot to tell. May I take some of your time ? Case 1259743

5

The bug will get processed by QA first, I’ll take a look afterwards :slight_smile:

1 Like
6

@segant Hi! I finally managed to take a look at your bug report. This is caused by OpenGL and other APIs having different rules for selecting a provoking vertex (the vertex that defines the value for fragment shading when this value is not interpolated). For GL it’s the last vertex, all other APIs use the first.
You can just change your geometry shader to output the ID of the first vertex for all three vertices you output there (e.g. o.vertexIdPassed=i[0].id;).