Updating Landscape during runtime

Development Programming & Scripting C++
1

Hi all!

I’m trying to dynamically update Landscape components during runtime, but hit a wall and need some help.
Here’s what I got so far.


void ATerrainImporter::CreateTerrain()
{
	// Generate 8x8 array with height 65000
	uint16 *Heights;
	GenerateHeights(8, 8, 65000, &Heights);

	for (TActorIterator<ALandscapeProxy> ActorItr(GetWorld()); ActorItr; ++ActorItr)
	{
		TArray<ULandscapeHeightfieldCollisionComponent*> Components = ActorItr->CollisionComponents;

		for (int c = 0; c < Components.Num(); c++)
		{
			UpdateTexture(Components[c]->RenderComponent->HeightmapTexture, Heights);
			//UpdateCollision(Components[c], Heights);
		}
	}

	delete] Heights;
}

The visible height of the terrain DOES change, but appears completely black and stops casting shadow (even with only Movable light sources).
Unfortunately, I can’t find a way to update the colliders - function ‘UpdateCollision’ is the closest I could get to finding what seemed collision related, but doesn’t work and can randomly crash the editor.

Landscape->Import(…) is a no-go, since it only works inside editor.

Any ideas?


void UpdateTexture(UTexture2D *InTexture, uint16 *InSource)
{
	for (int m = 0; m < InTexture->PlatformData->Mips.Num(); m++)
	{
		uint16 *Dest = (uint16*)InTexture->PlatformData->Mips[m].BulkData.Lock(LOCK_READ_WRITE);

		// How many pixels to advance for given Mip level
		uint16 StepX = (uint16)pow(2.0f, m);	
		uint16 StepY = (StepX - 1) * InTexture->PlatformData->Mips[0].SizeX;

		for (uint16 y = 0; y < InTexture->PlatformData->Mips[m].SizeY; y++, InSource += StepY)
			for (uint16 x = 0; x < InTexture->PlatformData->Mips[m].SizeX; x++, InSource += StepX)
			{
				*(Dest++) = *InSource;
				// No idea what the reverse is used for, but doesn't work otherwise
				*(Dest++) = Reverse(*InSource);
			}

		// Reset Source
		InSource -= InTexture->PlatformData->Mips[0].SizeX * InTexture->PlatformData->Mips[0].SizeY;
		InTexture->PlatformData->Mips[m].BulkData.Unlock();
	}

	InTexture->UpdateResource();
}



void UpdateCollision(ULandscapeHeightfieldCollisionComponent* InComponent, uint16 *InSource)
{
	uint16 *Dest = (uint16*)InComponent->CollisionHeightData.Lock(LOCK_READ_WRITE);

	for (int i = 0; i < InComponent->CollisionHeightData.GetElementCount(); i++, InSource++, Dest++)
		*Dest = *InSource;

	InComponent->CollisionHeightData.Unlock();

	// Editor only
	//Components[c]->UpdateHeightfieldRegion(0, 0, 1, 1);
}
2

Hi,

Did you managed to go further on this?

3

Any luck with this? hoping to do the same thing!

4

Phoboz, have you managed to fix the collisions issue? I’d need an invisible but deforming and colliding terrain but no idea how to pull it off.

5

Im intersted in this topic too, but now is too early for me to working with it. But when Im looking at this…

Collision update fails probably because ULandscapeHeightfieldCollisionComponent::CollisionHeightData is marked with WITH_EDITORONLY_DATA.
Some time ago I read that navigation system is updated in run-time based on height data through TRefCountPtr<FPhysXHeightfieldRef> HeightfieldRef.

FPhysXHeightfieldRef is a struct that hold pointers to PhysX structures RBHeightfield and RBHeightfieldSimple, both of PhysX type PxHeightfield.
The PxHeightfield has a method modifySamples.

IMHO it is worth to look into the functions:

  • void ULandscapeHeightfieldCollisionComponent::CreatePhysicsState() (LandscapeCollision.cpp)
  • virtual void ExportPxHeightField(physx::PxHeightField const * const HeightField, const FTransform& LocalToWorld) (RecastNavMeshGenerator.cpp)

Deeper digging in engine code and another interesting function

  • ConvertHeightfieldDataForPhysx ( alse LandscapeCollision.cpp)
1 Like
6

In a topic i created with a pretty different question somebody (sorta) mentioned this plugin: Runtime Mesh Component
And (having seen this topic earlier) i was just thinking this may actually be what you guys are looking for, im sure you can can make some landscape out of tiles of that.
Just a thought :slight_smile: