[SOLVED] Compute shader occlusion test only works with scene camera

Compute shader occlusion test only works with scene camera

Using Unity 2022.3.40f1 and URP.

I'm trying to implement occlusion culling with the depth buffer in a compute shader.

I don't know what's wrong here but my code only works fine with the scene camera but not the game camera.
I have already debugged the depth texture and it works fine.

Any ideas what's missing here?

My shader setup looks like this:

void Render (uint3 id : SV_DispatchThreadID)
{
 
    Chunk chunk = chunkBuffer[id.x];
 
    float4 clipPos = UnityWorldToClipPos(chunk.position);
    float2 screenPos = ComputeScreenPos(clipPos);
    
    float4 projectedPos = mul(UNITY_MATRIX_VP, float4(chunk.position, 1.0f));
    float2 projectedUV = (projectedPos.xy / projectedPos.w + 1.0f) * 0.5f; 
    
    float sceneDepth = _DepthTexture.SampleLevel(sampler_DepthTexture, projectedUV, 0).r;
    
    float chunkDepth = (projectedPos.z / projectedPos.w);
    if (chunkDepth < sceneDepth) {
      return; //  is occluded
    }
}

Solution

The issue was UNITY_MATRIX_VP. I had to calculate my own view projection matrix like this: GL.GetGPUProjectionMatrix(_cam.projectionMatrix, false) * _cam.worldToCameraMatrix;