RTLensEngineAdapter.cpp

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// Copyright (c) 2026 Computer Vision Center (CVC) at the Universitat Autonoma
// de Barcelona (UAB).
//
// This work is licensed under the terms of the MIT license.
// For a copy, see <https://opensource.org/licenses/MIT>.
 
#include "Carla/Sensor/RTLensEngineAdapter.h"
#include "Carla.h"
 
#include <util/ue-header-guard-begin.h>
#include "HAL/IConsoleManager.h"
#include <util/ue-header-guard-end.h>
 
namespace RTLensEngineAdapter
{
 
void SetBlockingRayTracingPipelineCreation(bool bBlocking)
{
  static IConsoleVariable *CVar =
      IConsoleManager::Get().FindConsoleVariable(TEXT("r.RayTracing.NonBlockingPipelineCreation"));
  // Value the engine had before this sensor overrode it; INDEX_NONE while not
  // overridden.
  static int32 ValueBeforeOverride = INDEX_NONE;
  static bool bWarnedConsoleOverride = false;
 
  if (CVar == nullptr)
  {
    return; // engine built without the cvar (no ray tracing support)
  }
 
  if (!bBlocking)
  {
    if (ValueBeforeOverride != INDEX_NONE)
    {
      CVar->Set(ValueBeforeOverride, ECVF_SetByCode);
      UE_LOG(LogCarla, Log,
          TEXT("rt_lens: asynchronous mode, r.RayTracing.NonBlockingPipelineCreation restored to %d"),
          ValueBeforeOverride);
      ValueBeforeOverride = INDEX_NONE;
    }
    return;
  }
 
  if (CVar->GetInt() == 0)
  {
    return; // already blocking (by us, by the ini or by the console)
  }
 
  // SetByConsole outranks SetByCode: the user forced non-blocking creation on
  // purpose; say once what that costs and respect it.
  if (((uint32)CVar->GetFlags() & ECVF_SetByMask) > (uint32)ECVF_SetByCode)
  {
    if (!bWarnedConsoleOverride)
    {
      bWarnedConsoleOverride = true;
      UE_LOG(LogCarla, Warning,
          TEXT("rt_lens: r.RayTracing.NonBlockingPipelineCreation is forced to %d from the console; ")
          TEXT("synchronous-mode frames will miss freshly spawned actors while their ray tracing ")
          TEXT("pipeline compiles (they render with the black, untagged PathTracingDefaultOpaqueCHS)."),
          CVar->GetInt());
    }
    return;
  }
 
  ValueBeforeOverride = CVar->GetInt();
  CVar->Set(0, ECVF_SetByCode);
  UE_LOG(LogCarla, Log,
      TEXT("rt_lens: synchronous mode, r.RayTracing.NonBlockingPipelineCreation 0 (was %d): ")
      TEXT("captures wait for the ray tracing material pipeline instead of rendering new actors ")
      TEXT("with the fallback hit shader"),
      ValueBeforeOverride);
}
 
void ApplyLensModel(FPostProcessSettings &PostProcessSettings, const FLensModelDescriptor &Descriptor)
{
  PostProcessSettings.bOverride_PathTracingLensModel = true;
  PostProcessSettings.bOverride_PathTracingLensFocal = true;
  PostProcessSettings.bOverride_PathTracingLensCoeffs01 = true;
  PostProcessSettings.bOverride_PathTracingLensCoeffs23 = true;
  PostProcessSettings.bOverride_PathTracingLensThetaMax = true;
  PostProcessSettings.bOverride_PathTracingLensCAScale = true;
 
  PostProcessSettings.PathTracingLensModel = (int32)Descriptor.Model;
 
  PostProcessSettings.PathTracingLensFocal = FVector4(
      Descriptor.FocalX, Descriptor.FocalY, Descriptor.CenterX, Descriptor.CenterY);
 
  // Model-specific packing (see CameraModelUtil.h): KannalaBrandt uses
  // Coeffs[0..3], BrownConrady uses Coeffs[0..4] (p2 lands in Coeffs23.X, see
  // the Scene.h field comment). Unused trailing slots are zero-filled.
  const auto CoeffAt = [&Descriptor](int32 i) -> float
  {
    return Descriptor.Coeffs.IsValidIndex(i) ? Descriptor.Coeffs[i] : 0.0f;
  };
  PostProcessSettings.PathTracingLensCoeffs01 = FVector4(
      CoeffAt(0), CoeffAt(1), CoeffAt(2), CoeffAt(3));
  PostProcessSettings.PathTracingLensCoeffs23 = FVector4(
      CoeffAt(4), CoeffAt(5), CoeffAt(6), CoeffAt(7));
 
  PostProcessSettings.PathTracingLensThetaMax = Descriptor.ThetaMax;
  PostProcessSettings.PathTracingLensCAScale = FVector2f(Descriptor.CAScaleR, Descriptor.CAScaleB);
 
  if (Descriptor.Model == ECameraModel::LUT1D && Descriptor.LUT.Num() > 0)
  {
    // TODO(rt-lens-engine): FPostProcessSettings has no per-view LUT resource
    // slot yet (a buffer, not a handful of scalars -- doesn't fit the
    // PathTracingLens* field pattern). LUT1D cameras currently render with
    // whatever LensModels.ush falls back to when no LUT is bound.
    UE_LOG(LogCarla, Warning,
        TEXT("RTLensEngineAdapter: camera_model=lut has no per-view upload path for its LUT ")
        TEXT("samples yet; the path tracer will not see them."));
  }
}
 
} // namespace RTLensEngineAdapter