o3de/Gems/PhysX/Code/Source/Pipeline/HeightFieldAssetHandler.cpp

/*
 * Copyright (c) Contributors to the Open 3D Engine Project.
 * For complete copyright and license terms please see the LICENSE at the root of this distribution.
 *
 * SPDX-License-Identifier: Apache-2.0 OR MIT
 *
 */


#include <Pipeline/HeightFieldAssetHandler.h>
#include <Pipeline/StreamWrapper.h>
#include <AzCore/IO/GenericStreams.h>
#include <AzCore/IO/FileIO.h>
#include <PhysX/HeightFieldAsset.h>
#include <PhysX/SystemComponentBus.h>
#include <PhysX/ComponentTypeIds.h>
#include <Source/Pipeline/HeightFieldAssetHandler.h>
#include <PxPhysicsAPI.h>

#include <extensions/PxSerialization.h>
#include <extensions/PxDefaultStreams.h>

namespace PhysX
{
    namespace Pipeline
    {
        const char* HeightFieldAssetHandler::s_assetFileExtension = "pxheightfield";

        HeightFieldAssetHandler::HeightFieldAssetHandler()
        {
            Register();
        }

        HeightFieldAssetHandler::~HeightFieldAssetHandler()
        {
            Unregister();
        }

        void HeightFieldAssetHandler::Register()
        {
            bool assetManagerReady = AZ::Data::AssetManager::IsReady();
            AZ_Error("PhysX HeightField Asset", assetManagerReady, "Asset manager isn't ready.");
            if (assetManagerReady)
            {
                AZ::Data::AssetManager::Instance().RegisterHandler(this, AZ::AzTypeInfo<HeightFieldAsset>::Uuid());
            }

            AZ::AssetTypeInfoBus::Handler::BusConnect(AZ::AzTypeInfo<HeightFieldAsset>::Uuid());
        }

        void HeightFieldAssetHandler::Unregister()
        {
            AZ::AssetTypeInfoBus::Handler::BusDisconnect();

            if (AZ::Data::AssetManager::IsReady())
            {
                AZ::Data::AssetManager::Instance().UnregisterHandler(this);
            }
        }

        // AZ::AssetTypeInfoBus
        AZ::Data::AssetType HeightFieldAssetHandler::GetAssetType() const
        {
            return AZ::AzTypeInfo<HeightFieldAsset>::Uuid();
        }

        void HeightFieldAssetHandler::GetAssetTypeExtensions(AZStd::vector<AZStd::string>& extensions)
        {
            extensions.push_back(HeightFieldAssetHandler::s_assetFileExtension);
        }

        const char* HeightFieldAssetHandler::GetAssetTypeDisplayName() const
        {
            return "PhysX HeightField Mesh";
        }

        const char* HeightFieldAssetHandler::GetBrowserIcon() const
        {
            return "Icons/Components/ColliderMesh.svg";
        }

        const char* HeightFieldAssetHandler::GetGroup() const
        {
            return "Physics";
        }

        AZ::Uuid HeightFieldAssetHandler::GetComponentTypeId() const
        {
            return PhysX::EditorTerrainComponentTypeId;
        }

        // AZ::Data::AssetHandler
        AZ::Data::AssetPtr HeightFieldAssetHandler::CreateAsset([[maybe_unused]] const AZ::Data::AssetId& id, const AZ::Data::AssetType& type)
        {
            if (type == AZ::AzTypeInfo<HeightFieldAsset>::Uuid())
            {
                return aznew HeightFieldAsset();
            }

            AZ_Error("PhysX HeightField Asset", false, "This handler deals only with PhysXHeightFieldAsset type.");
            return nullptr;
        }

        AZ::Data::AssetHandler::LoadResult HeightFieldAssetHandler::LoadAssetData(
            const AZ::Data::Asset<AZ::Data::AssetData>& asset,
            AZStd::shared_ptr<AZ::Data::AssetDataStream> stream,
            [[maybe_unused]] const AZ::Data::AssetFilterCB& assetLoadFilterCB)
        {
            AZ_PROFILE_FUNCTION(Physics);

            HeightFieldAsset* physXHeightFieldAsset = asset.GetAs<HeightFieldAsset>();
            if (!physXHeightFieldAsset)
            {
                AZ_Error("PhysX HeightField Asset", false, "This should be a PhysX HeightField Asset, as this is the only type we process.");
                return AZ::Data::AssetHandler::LoadResult::Error;
            }
            
            // Wrap az stream behind physx interface
            PhysX::AssetDataStreamWrapper readerStream(stream);

            // Read the file header
            HeightFieldAssetHeader header;
            readerStream.read(&header, sizeof(header));

            // Parse the asset versions
            if (header.m_assetVersion >= 1)
            {
                if (header.m_assetDataSize > 0)
                {
                    // Version 1 doesn't have min/max heights, so only read this data for versions 2+.
                    if (header.m_assetVersion >= 2)
                    {
                        readerStream.read(&physXHeightFieldAsset->m_minHeight, sizeof(float));
                        readerStream.read(&physXHeightFieldAsset->m_maxHeight, sizeof(float));
                    }
                    else
                    {
                        // In versions 0 & 1, the data is cooked assuming the data starts at origin (min height = 0)
                        // and has a max height of 1024.0f.
                        const float v1HardCodedMaxHeight = 1024.0f;
                        physXHeightFieldAsset->m_minHeight = 0.0f;
                        physXHeightFieldAsset->m_maxHeight = v1HardCodedMaxHeight;
                    }

                    // Create heightfield from cooked file
                    physx::PxPhysics& physx = PxGetPhysics();
                    physXHeightFieldAsset->SetHeightField(physx.createHeightField(readerStream));

                    AZ_Error("PhysX HeightField Asset", physXHeightFieldAsset->m_heightField != nullptr, "Failed to construct PhysX mesh from the cooked data. Possible data corruption.");
                    return (physXHeightFieldAsset->m_heightField != nullptr) ?
                        AZ::Data::AssetHandler::LoadResult::LoadComplete :
                        AZ::Data::AssetHandler::LoadResult::Error;
                }
                else
                {
                    AZ_Warning("HeightFieldAssetHandler", false, "Empty heightfield file. Try resaving your level");
                }
            }
            else
            {
                AZ_Warning("HeightFieldAssetHandler", false, "Unsupported asset version");
            }

            return AZ::Data::AssetHandler::LoadResult::Error;
        }

        bool HeightFieldAssetHandler::SaveAssetData(const AZ::Data::Asset<AZ::Data::AssetData>& asset, AZ::IO::GenericStream* stream)
        {
            AZ_PROFILE_FUNCTION(Physics);

            HeightFieldAsset* physXHeightFieldAsset = asset.GetAs<HeightFieldAsset>();
            if (!physXHeightFieldAsset)
            {
                AZ_Error("PhysX HeightField Asset", false, "This should be a PhysX HeightField Asset. HeightFieldAssetHandler doesn't handle any other asset type.");
                return false;
            }

            physx::PxHeightField* heightField = physXHeightFieldAsset->GetHeightField();
            if (!heightField)
            {
                AZ_Warning("PhysX HeightField Asset", false, "There is no heightfield to save.");
                return false;
            }

            HeightFieldAssetHeader header;
            if (header.m_assetVersion == 2)
            {
                physx::PxCooking* cooking = nullptr;
                SystemRequestsBus::BroadcastResult(cooking, &SystemRequests::GetCooking);

                // Read samples from heightfield
                AZStd::vector<physx::PxHeightFieldSample> samples;
                samples.resize(heightField->getNbColumns() * heightField->getNbRows());
                heightField->saveCells(samples.data(), (physx::PxU32)samples.size() * heightField->getSampleStride());

                // Read description from heightfield
                physx::PxHeightFieldDesc heightFieldDesc;
                heightFieldDesc.format = heightField->getFormat();
                heightFieldDesc.nbColumns = heightField->getNbColumns();
                heightFieldDesc.nbRows = heightField->getNbRows();
                heightFieldDesc.samples.data = samples.data();
                heightFieldDesc.samples.stride = heightField->getSampleStride();

                // Cook description to file
                physx::PxDefaultMemoryOutputStream writer;
                bool success = cooking->cookHeightField(heightFieldDesc, writer);
                header.m_assetDataSize = writer.getSize() + 2 * sizeof(float);

                PhysX::StreamWrapper writerStream(stream);
                writerStream.write(&header, sizeof(header));
                writerStream.write(&physXHeightFieldAsset->m_minHeight, sizeof(physXHeightFieldAsset->m_minHeight));
                writerStream.write(&physXHeightFieldAsset->m_maxHeight, sizeof(physXHeightFieldAsset->m_maxHeight));
                writerStream.write(writer.getData(), writer.getSize());

                return success;
            }
            else
            {
                AZ_Warning("HeightFieldAssetHandler", false, "Unsupported asset version");
            }

            return false;
        }

        void HeightFieldAssetHandler::DestroyAsset(AZ::Data::AssetPtr ptr)
        {
            delete ptr;
        }

        void HeightFieldAssetHandler::GetHandledAssetTypes(AZStd::vector<AZ::Data::AssetType>& assetTypes)
        {
            assetTypes.push_back(AZ::AzTypeInfo<HeightFieldAsset>::Uuid());
        }
    } //namespace Pipeline
} // namespace PhysX