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Maciej Sawicki
Maciej Sawicki

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[Game of Purpose] Day 59 - Following a path either by distance or Spline points

#gamedev

Today I was playing around with supporting 2 ways of following a path.

  • By distance - Given a path it moves to a point every x distance.
  • By points - Given a path it moves to each point the Spline has configured.

https://blueprintue.com/blueprint/zmunmar-/

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And my full path-following code looks like this:

#pragma once  #include "CoreMinimal.h" #include "Components/ActorComponent.h" #include "Components/SplineComponent.h" #include "DrawDebugHelpers.h" #include "SplineFollowerBase.generated.h"  UENUM(BlueprintType) enum class EFollowingType : uint8 { ByDistance UMETA(DisplayName = "By Distance"), ByPoints UMETA(DisplayName="By Points") }; UCLASS(BlueprintType, Blueprintable) class SKY_PATROL_API USplineFollowerBase : public UActorComponent { GENERATED_BODY() public: UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Spline") USplineComponent* TargetSpline; UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Spline") float DistanceToMove = 200.0f; UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Spline") EFollowingType FollowingType = EFollowingType::ByDistance; protected: UFUNCTION(BlueprintCallable) UPARAM(DisplayName="NextTargetDistance") float CalculateNextTargetDistanceBase(); UFUNCTION(BlueprintCallable) UPARAM(DisplayName="NextPointIndex") int CalculateNextPointIndexBase(); private: float NextTargetDistance = -1.0f; int NextPointIndex = -1; };
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#include "SplineFollowerBase.h"  #include "Utils/MyStringUtils.h"  float USplineFollowerBase::CalculateNextTargetDistanceBase() { check(TargetSpline != nullptr); const auto TargetSplineTotalLength = TargetSpline->GetSplineLength(); // staring the movement if (NextTargetDistance < 0.0f) { NextTargetDistance = 0.0f; } // looping else if (NextTargetDistance >= TargetSplineTotalLength) { NextTargetDistance = 0.0f; } else { NextTargetDistance = FMath::Clamp(NextTargetDistance + DistanceToMove, 0.0f, TargetSplineTotalLength); } PrintString(FString::Printf(TEXT("NextTargetDistance: %f"), NextTargetDistance)); return NextTargetDistance; } int USplineFollowerBase::CalculateNextPointIndexBase() { check(TargetSpline != nullptr); const auto TargetSplineTotalPoints = TargetSpline->GetNumberOfSplinePoints(); NextPointIndex = (NextPointIndex + 1) % TargetSplineTotalPoints; PrintString(FString::Printf(TEXT("NextPointIndex: %d"), NextPointIndex)); return NextPointIndex; }
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