URP multi pass PostProcess shader SetVector failed.

Unity Engine
, ,
1

I create a multi pass shader for postprocess

SubShader
{
        Tags { "RenderType" = "Opaque" "RenderPipeline" = "UniversalPipeline"}
        LOD 100
        ZTest Always ZWrite Off Cull Off

Pass A
{
...
}

Pass B
{
...
}

}

then i draw a fullscreen pass five times

for (int i = 0; i < 5; i++)
{
Vector4 params = ...
material.SetVector("paramsName", params);
cmd.DrawMesh(RenderingUtils.fullscreenMesh, Matrix4x4.identity, material, 0, 0);
}

I use renderdoc to debug it, i found that in drawcall 0(i =0), the params value is the drawcall 4(i=4)'s value.
It seems that unity don’t push the value to the gpu in drawcall 0.
How to fix that? Thanks.

2

It’s likely because Material.SetVector executes the moment it’s being called. Whilst CommandBuffer commands are queued and executed at a later stage.

You can use cmd.SetGlobalVector instead, that’s sure to work.

1 Like
3

It works now, Thanks.