RayTracer.cpp

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// Copyright (c) 2020 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.h"
#include "Carla/Util/RayTracer.h"
 
#include "Carla/Game/CarlaStatics.h"
 
 
namespace crp = carla::rpc;
 
// 发射一条射线，并返回射线与场景中物体的所有交点信息。
// 该函数通过 `LineTraceMultiByChannel` 方法进行射线检测，收集所有与射线相交的物体信息。
// 每个交点的信息包括交点位置和物体的标签（标签由 `ATagger::GetTagOfTaggedComponent` 获取）。
std::vector<crp::LabelledPoint> URayTracer::CastRay(
    FVector StartLocation, FVector EndLocation, UWorld * World)
{
  TArray<FHitResult> OutHits;
  World->LineTraceMultiByChannel(
      OutHits,
      StartLocation,
      EndLocation,
      ECC_GameTraceChannel3, // overlap channel
      FCollisionQueryParams(),
      FCollisionResponseParams()
  );
  std::vector<crp::LabelledPoint> result;
  for (auto& Hit : OutHits)
  {
    UPrimitiveComponent* Component = Hit.GetComponent();
    crp::CityObjectLabel ComponentTag =
        ATagger::GetTagOfTaggedComponent(*Component);
 
    FVector UELocation = Hit.Location;
    ACarlaGameModeBase* GameMode = UCarlaStatics::GetGameMode(World);
    ALargeMapManager* LargeMap = GameMode->GetLMManager();
    if (LargeMap)
    {
      UELocation = LargeMap->LocalToGlobalLocation(UELocation);
    }
    result.emplace_back(crp::LabelledPoint(UELocation, ComponentTag));
  }
  return result;
}
 
std::pair<bool, crp::LabelledPoint> URayTracer::ProjectPoint(
    FVector StartLocation, FVector Direction, float MaxDistance, UWorld * World)
{
  FHitResult Hit;
  bool bDidHit = World->LineTraceSingleByChannel(
      Hit,
      StartLocation,
      StartLocation + Direction.GetSafeNormal() * MaxDistance,
      ECC_GameTraceChannel2, // camera
      FCollisionQueryParams(),
      FCollisionResponseParams()
  );
  if (bDidHit)
  {
    UPrimitiveComponent* Component = Hit.GetComponent();
    crp::CityObjectLabel ComponentTag =
        ATagger::GetTagOfTaggedComponent(*Component);
 
    FVector UELocation = Hit.Location;
    ACarlaGameModeBase* GameMode = UCarlaStatics::GetGameMode(World);
    ALargeMapManager* LargeMap = GameMode->GetLMManager();
    if (LargeMap)
    {
      UELocation = LargeMap->LocalToGlobalLocation(UELocation);
    }
    return std::make_pair(bDidHit, crp::LabelledPoint(UELocation, ComponentTag));
  }
  return std::make_pair(bDidHit, crp::LabelledPoint(FVector(0.0f,0.0f,0.0f), crp::CityObjectLabel::None));
}