Hi,
I think i found a bug in DrawProceduralIndirect in Unity 2022.1.4.f1
The baseVertexLocation and startInstanceLocation of the argument buffer are not being passed to the shader on DX11 and DX12 when using indirect drawing. It works as intended when switching to Vulkan.
I checked this with the indexBuffer versions of Graphics.DrawProceduralIndirect() and CommandBuffer.DrawProceduralIndirect().
Correct results on Vulkan:
SV_VertexID used to access vertex positions in a single “mesh-atlas” buffer:
SV_InstanceID used to offset objects:
Wrong results when switching the Editor to DX11 or DX12:
DX11 (SV_VertexID & SV_InstanceID are always starting at 0. Their values in the arguments buffer are being ignored / are not being passed to the shader):
DX12 (SV_VertexID & SV_InstanceID are always starting at 0. Their values in the arguments buffer are being ignored / are not being passed to the shader):
Is this a bug or intended behaviour?
Please note that the SV_InstanceID bug (if it is one), was already discussed/displayed in this thread from Feb 2017 in more detail. The SV_VertexID bug is not discussed in that thread though.
[Edit]
The shader that was used for testing
[Edit2]
Uploaded example project
Shader "CustomShader"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}
}
SubShader
{
Tags {
"LightMode" = "CustomSRP"
"RenderType" = "Opaque"
}
LOD 100
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
//ByteAddressBuffer _VertexPositions;
StructuredBuffer<float3> _VertexPositions;
struct appdata
{
uint vid : SV_VertexID;
uint instID : SV_InstanceID;
};
struct v2f
{
float4 vertex : SV_POSITION;
float3 debugColor : TEXCOORD0;
};
sampler2D _MainTex;
float4 _MainTex_ST;
v2f vert (appdata v)
{
v2f o;
//v.vid += 1224;
o.vertex = UnityObjectToClipPos(float4(_VertexPositions[v.vid] + float3(v.instID*10,0,0), 1));
o.debugColor = _VertexPositions[v.vid].xyz;
return o;
}
fixed4 frag (v2f i) : SV_Target
{
float4 col = float4(1,1,1,1);
col.rgb = i.debugColor.xyz * 0.2f;
return col;
}
ENDCG
}
}
}
8240757–1077612–ExampleProject.zip (79.2 KB)
