Method DrawDebugJoint

Source/URLab/Private/MuJoCo/Utils/MjUtils.cpp:281–405

}

void MjUtils::DrawDebugJoint(UWorld* World, const FVector& anchor, const FVector& Axis,
	int JointType, bool bLimited, float RangeMin, float RangeMax,
	float CurrentPos, float RefPos, float ArcRadius)
{
	if (!World)
		return;

	const FColor ArcColor(40, 200, 40);      // Bright green arc outline
	const FColor FillColor(40, 180, 40, 50); // Semi-transparent green fill
	const FColor LimitColor(220, 60, 60);    // Red limit marks
	const FColor PosColor(255, 220, 30);     // Yellow current position
	const FColor RefColor(180, 180, 220);    // Light blue-grey reference position
	FVector AxisDir = Axis.GetSafeNormal();

	// Negate all rotation angles: MuJoCo uses right-hand rule but the
	// axis has been Y-negated for UE's left-hand coordinate system.
	const float Sign = -1.0f;

	if (JointType == mjJNT_HINGE)
	{
		// Find a perpendicular radial direction
		FVector RadialDir = FVector::CrossProduct(AxisDir, FVector::UpVector);
		if (RadialDir.SizeSquared() < 1e-6f)
		{
			RadialDir = FVector::CrossProduct(AxisDir, FVector::RightVector);
		}
		RadialDir.Normalize();

		if (bLimited && (RangeMin != 0.0f || RangeMax != 0.0f))
		{
			// Compute draw angles (swap min/max since we negate)
			float DrawMin = Sign * RangeMax;
			float DrawMax = Sign * RangeMin;
			const int NumSegments = 48;
			float Span = DrawMax - DrawMin;
			float Step = Span / NumSegments;

			// Build arc points for reuse
			TArray<FVector> ArcPoints;
			ArcPoints.Reserve(NumSegments + 1);
			for (int i = 0; i <= NumSegments; ++i)
			{
				float Theta = DrawMin + Step * i;
				ArcPoints.Add(anchor + FQuat(AxisDir, Theta).RotateVector(RadialDir) * ArcRadius);
			}

			// Filled arc (triangle fan from anchor)
			TArray<FVector> FillVerts;
			TArray<int32> FillIndices;
			FillVerts.Add(anchor); // index 0 = center
			for (int i = 0; i <= NumSegments; ++i)
			{
				FillVerts.Add(ArcPoints[i]);
			}
			for (int i = 0; i < NumSegments; ++i)
			{
				FillIndices.Add(0);
				FillIndices.Add(i + 1);