Get PrimitiveID

I read that OpenGL exposes the gl_PrimitiveID in fragment shaders, which (I believe) tells you the ID of the triangle currently being rendered.

Is this accessible in Unity's Shader language?

If not: My goal is to color each triangle individually without applying a texture. I want to tint each triangle of UI elements (i.e. UI Sprites) differently. Any ideas?

 

https://anteru.net/blog/2016/mapping-between-hlsl-and-glsl/
For the most part the HLSL mappings on that page will work in Unity without any work.

 

Somehow the above url does not work anymore, this does:
https://anteru.net/blog/2016/mapping-between-HLSL-and-GLSL/

I was wondering if i could change SV_PrimitiveID in my shader, but i didn't get far. Maybe this helps someone else
https://www.khronos.org/opengl/wiki/Vertex_Rendering#Fixed_index_restart

 

What do you mean by "change SV_PrimitiveID in my shader"? You can "change" it with a geometry shader, by emitting more or less geometry, but I don't think you can restart it at 0. The OpenGL stuff you linked to happens in the CPU side rendering, not as part of the shader, and isn't something Unity exposes.

 

I don't use a geometry shader, only vert and frag with nointerpolation. I thought there might be a way to tell the GPU in my shader that it should use vertex 0 (or 1 or 2) as provoking vertex.

"There is a way to change the provoking vertex convention:
void glProvokingVertex(GLenum provokeMode);"
--> https://www.khronos.org/opengl/wiki/Primitive#Provoking_vertex

but i am completely misguided i guess