Terrain/sphrose/surface materials component (#4541)

* wip Signed-off-by: sphrose <82213493+sphrose@users.noreply.github.com> * wip Signed-off-by: sphrose <82213493+sphrose@users.noreply.github.com> * Terrain Surface Materials List Component. Signed-off-by: sphrose <82213493+sphrose@users.noreply.github.com> * fix erroneous commit Signed-off-by: sphrose <82213493+sphrose@users.noreply.github.com> * Added some comments. Signed-off-by: sphrose <82213493+sphrose@users.noreply.github.com> * Review changes. Signed-off-by: sphrose <82213493+sphrose@users.noreply.github.com> * Surface Materials list unit tests Signed-off-by: sphrose <82213493+sphrose@users.noreply.github.com> * Missing shape test Signed-off-by: sphrose <82213493+sphrose@users.noreply.github.com> * review changes. Signed-off-by: sphrose <82213493+sphrose@users.noreply.github.com> * Compile fix. Signed-off-by: sphrose <82213493+sphrose@users.noreply.github.com> * Fix case issue in include path. Signed-off-by: Ken Pruiksma <pruiksma@amazon.com> * replaced reverted test. Signed-off-by: sphrose <82213493+sphrose@users.noreply.github.com> Co-authored-by: Ken Pruiksma <pruiksma@amazon.com>
2021-10-18 15:37:07 +01:00
parent d0f18eefb3
commit bcc186f87f
13 changed files with 642 additions and 1 deletions
@@ -22,9 +22,12 @@ ly_add_target(
            Gem::Atom_RPI.Public
            Gem::Atom_Utils.Static
            Gem::Atom_Feature_Common
+            Gem::AtomLyIntegration_CommonFeatures.Static
            Gem::GradientSignal
            Gem::SurfaceData
            Gem::LmbrCentral
+            
+            
 )

 ly_add_target(
@@ -14,7 +14,8 @@ namespace Terrain
 {
    void EditorTerrainSurfaceGradientListComponent::Reflect(AZ::ReflectContext* context)
    {
-        BaseClassType::ReflectSubClass<EditorTerrainSurfaceGradientListComponent, BaseClassType>(context, 1,
+        BaseClassType::ReflectSubClass<EditorTerrainSurfaceGradientListComponent, BaseClassType>(
+            context, 1,
            &LmbrCentral::EditorWrappedComponentBaseVersionConverter<typename BaseClassType::WrappedComponentType,
            typename BaseClassType::WrappedConfigType, 1>
        );
@@ -14,6 +14,7 @@
 #include <EditorComponents/EditorTerrainWorldComponent.h>
 #include <EditorComponents/EditorTerrainWorldDebuggerComponent.h>
 #include <EditorComponents/EditorTerrainWorldRendererComponent.h>
+#include <TerrainRenderer/EditorComponents/EditorTerrainSurfaceMaterialsListComponent.h>
 #include <TerrainRenderer/EditorComponents/EditorTerrainMacroMaterialComponent.h>

 namespace Terrain
@@ -28,6 +29,7 @@ namespace Terrain
                Terrain::EditorTerrainMacroMaterialComponent::CreateDescriptor(),
                Terrain::EditorTerrainSurfaceGradientListComponent::CreateDescriptor(),
                Terrain::EditorTerrainSystemComponent::CreateDescriptor(),
+                Terrain::EditorTerrainSurfaceMaterialsListComponent::CreateDescriptor(),
                Terrain::EditorTerrainWorldComponent::CreateDescriptor(),
                Terrain::EditorTerrainWorldDebuggerComponent::CreateDescriptor(),
                Terrain::EditorTerrainWorldRendererComponent::CreateDescriptor(),
@@ -18,6 +18,7 @@
 #include <Components/TerrainLayerSpawnerComponent.h>
 #include <Components/TerrainSurfaceGradientListComponent.h>
 #include <Components/TerrainSurfaceDataSystemComponent.h>
+#include <TerrainRenderer/Components/TerrainSurfaceMaterialsListComponent.h>
 #include <TerrainRenderer/Components/TerrainMacroMaterialComponent.h>

 namespace Terrain
@@ -26,6 +27,7 @@ namespace Terrain
        : AZ::Module()
    {
        m_descriptors.insert(m_descriptors.end(), {
+                TerrainSurfaceMaterialsListComponent::CreateDescriptor(),
                TerrainSystemComponent::CreateDescriptor(),
                TerrainWorldComponent::CreateDescriptor(),
                TerrainWorldDebuggerComponent::CreateDescriptor(),
@@ -0,0 +1,305 @@
+/*
+ * 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 <TerrainRenderer/Components/TerrainSurfaceMaterialsListComponent.h>
+
+#include <AzCore/Asset/AssetManagerBus.h>
+#include <AzCore/Component/Entity.h>
+#include <AzCore/Asset/AssetManager.h>
+#include <AzCore/Asset/AssetSerializer.h>
+#include <AzCore/RTTI/BehaviorContext.h>
+#include <AzCore/Serialization/EditContext.h>
+#include <AzCore/Serialization/SerializeContext.h>
+#include <AzCore/Math/Aabb.h>
+#include <AzCore/std/smart_ptr/make_shared.h>
+
+#include <GradientSignal/Ebuses/GradientRequestBus.h>
+#include <SurfaceData/SurfaceDataProviderRequestBus.h>
+
+#include <AtomLyIntegration/CommonFeatures/Material/MaterialComponentBus.h>
+
+#include <TerrainSystem/TerrainSystemBus.h>
+
+namespace Terrain
+{
+    void TerrainSurfaceMaterialMapping::Reflect(AZ::ReflectContext* context)
+    {
+        if (auto serialize = azrtti_cast<AZ::SerializeContext*>(context))
+        {
+            serialize->Class<TerrainSurfaceMaterialMapping>()
+                ->Version(1)
+                ->Field("Surface", &TerrainSurfaceMaterialMapping::m_surfaceTag)
+                ->Field("MaterialAsset", &TerrainSurfaceMaterialMapping::m_materialAsset);
+
+            if (auto edit = serialize->GetEditContext())
+            {
+                edit->Class<TerrainSurfaceMaterialMapping>("Terrain Surface Gradient Mapping", "Mapping between a surface and a material.")
+                    ->ClassElement(AZ::Edit::ClassElements::EditorData, "")
+                    ->Attribute(AZ::Edit::Attributes::AutoExpand, true)
+                    ->Attribute(AZ::Edit::Attributes::Visibility, AZ::Edit::PropertyVisibility::Show)
+
+                    ->DataElement(AZ::Edit::UIHandlers::ComboBox, &TerrainSurfaceMaterialMapping::m_surfaceTag, "Surface Tag", "Surface type to map to a material.")
+                    ->DataElement(AZ::Edit::UIHandlers::Default, &TerrainSurfaceMaterialMapping::m_materialAsset, "Material Asset", "")
+                    ->Attribute(AZ::Edit::Attributes::AutoExpand, true)
+                    ->Attribute(AZ::Edit::Attributes::ShowProductAssetFileName, true)
+                    ;
+            }
+        }
+    }
+
+    void TerrainSurfaceMaterialsListConfig::Reflect(AZ::ReflectContext* context)
+    {
+        TerrainSurfaceMaterialMapping::Reflect(context);
+
+        AZ::SerializeContext* serialize = azrtti_cast<AZ::SerializeContext*>(context);
+        if (serialize)
+        {
+            serialize->Class<TerrainSurfaceMaterialsListConfig, AZ::ComponentConfig>()
+                ->Version(1)
+                ->Field("Mappings", &TerrainSurfaceMaterialsListConfig::m_surfaceMaterials);
+
+            AZ::EditContext* edit = serialize->GetEditContext();
+            if (edit)
+            {
+                edit->Class<TerrainSurfaceMaterialsListConfig>(
+                        "Terrain Surface Material List Component", "Provide mapping between surfaces and render materials.")
+                    ->ClassElement(AZ::Edit::ClassElements::EditorData, "")
+                    ->Attribute(AZ::Edit::Attributes::Visibility, AZ::Edit::PropertyVisibility::Show)
+                    ->Attribute(AZ::Edit::Attributes::AutoExpand, true)
+
+                    ->DataElement(
+                        AZ::Edit::UIHandlers::Default, &TerrainSurfaceMaterialsListConfig::m_surfaceMaterials,
+                        "Gradient to Material Mappings", "Maps surfaces to materials.");
+            }
+        }
+    }
+
+    void TerrainSurfaceMaterialsListComponent::GetProvidedServices(AZ::ComponentDescriptor::DependencyArrayType& services)
+    {
+        services.push_back(AZ_CRC_CE("TerrainMaterialProviderService"));
+    }
+
+    void TerrainSurfaceMaterialsListComponent::GetIncompatibleServices(AZ::ComponentDescriptor::DependencyArrayType& services)
+    {
+        services.push_back(AZ_CRC_CE("TerrainMaterialProviderService"));
+    }
+
+    void TerrainSurfaceMaterialsListComponent::GetRequiredServices(AZ::ComponentDescriptor::DependencyArrayType& services)
+    {
+        services.push_back(AZ_CRC_CE("AxisAlignedBoxShapeService"));
+    }
+
+    void TerrainSurfaceMaterialsListComponent::Reflect(AZ::ReflectContext* context)
+    {
+        TerrainSurfaceMaterialsListConfig::Reflect(context);
+
+        AZ::SerializeContext* serialize = azrtti_cast<AZ::SerializeContext*>(context);
+        if (serialize)
+        {
+            serialize->Class<TerrainSurfaceMaterialsListComponent, AZ::Component>()
+                ->Version(0)
+                ->Field("Configuration", &TerrainSurfaceMaterialsListComponent::m_configuration);
+        }
+    }
+
+    TerrainSurfaceMaterialsListComponent::TerrainSurfaceMaterialsListComponent(const TerrainSurfaceMaterialsListConfig& configuration)
+        : m_configuration(configuration)
+    {
+    }
+
+    void TerrainSurfaceMaterialsListComponent::Activate()
+    {
+        m_cachedAabb = AZ::Aabb::CreateNull();
+
+        // Set all the materials as inactive and start loading.
+        for (auto& surfaceMaterialMapping : m_configuration.m_surfaceMaterials)
+        {
+            if (surfaceMaterialMapping.m_materialAsset.GetId().IsValid())
+            {
+                surfaceMaterialMapping.m_active = false;
+                surfaceMaterialMapping.m_materialAsset.QueueLoad();
+                AZ::Data::AssetBus::Handler::BusConnect(surfaceMaterialMapping.m_materialAsset.GetId());
+            }
+        }
+    }
+
+    void TerrainSurfaceMaterialsListComponent::Deactivate()
+    {
+        TerrainAreaMaterialRequestBus::Handler::BusDisconnect();
+
+        for (auto& surfaceMaterialMapping : m_configuration.m_surfaceMaterials)
+        {
+            if (surfaceMaterialMapping.m_materialAsset.GetId().IsValid())
+            {
+                AZ::Data::AssetBus::Handler::BusDisconnect(surfaceMaterialMapping.m_materialAsset.GetId());
+                surfaceMaterialMapping.m_materialAsset.Release();
+                surfaceMaterialMapping.m_materialInstance.reset();
+                surfaceMaterialMapping.m_activeMaterialAssetId = AZ::Data::AssetId();
+            }
+        }
+
+        HandleMaterialStateChanges();
+    }
+
+    int TerrainSurfaceMaterialsListComponent::CountMaterialIDInstances(AZ::Data::AssetId id) const
+    {
+        int count = 0;
+
+        for (const auto& surfaceMaterialMapping : m_configuration.m_surfaceMaterials)
+        {
+            if (surfaceMaterialMapping.m_activeMaterialAssetId == id)
+            {
+                count++;
+            }
+        }
+
+        return count;
+    }
+
+    void TerrainSurfaceMaterialsListComponent::HandleMaterialStateChanges()
+    {
+        bool anyMaterialIsActive = false;
+        bool anyMaterialWasAlreadyActive = false;
+
+        for (auto& surfaceMaterialMapping : m_configuration.m_surfaceMaterials)
+        {
+            const bool wasPreviouslyActive = surfaceMaterialMapping.m_active;
+            const bool isNowActive = (surfaceMaterialMapping.m_materialInstance != nullptr);
+
+            if (wasPreviouslyActive)
+            {
+                anyMaterialWasAlreadyActive = true;
+            }
+
+            if (isNowActive)
+            {
+                anyMaterialIsActive = true;
+            }
+
+            surfaceMaterialMapping.m_active = isNowActive;
+
+            if (!wasPreviouslyActive && !isNowActive)
+            {
+                // A material has been assigned but has not yet completed loading.
+            }
+            else if (!wasPreviouslyActive && isNowActive)
+            {
+                // Remember the asset id so we can disconnect from the AssetBus if the material asset is removed.
+                surfaceMaterialMapping.m_activeMaterialAssetId = surfaceMaterialMapping.m_materialAsset.GetId();
+
+                TerrainAreaMaterialNotificationBus::Broadcast(
+                    &TerrainAreaMaterialNotificationBus::Events::OnTerrainSurfaceMaterialMappingCreated, GetEntityId(),
+                    surfaceMaterialMapping.m_surfaceTag,
+                    surfaceMaterialMapping.m_materialInstance);
+            }
+            else if (wasPreviouslyActive && !isNowActive)
+            {
+                // Don't disconnect from the AssetBus if this material is mapped more than once.
+                if (CountMaterialIDInstances(surfaceMaterialMapping.m_activeMaterialAssetId) == 1)
+                {
+                    AZ::Data::AssetBus::Handler::BusDisconnect(surfaceMaterialMapping.m_activeMaterialAssetId);
+                }
+
+                surfaceMaterialMapping.m_activeMaterialAssetId = AZ::Data::AssetId();
+
+                TerrainAreaMaterialNotificationBus::Broadcast(
+                    &TerrainAreaMaterialNotificationBus::Events::OnTerrainSurfaceMaterialMappingDestroyed, GetEntityId(),
+                    surfaceMaterialMapping.m_surfaceTag);
+            }
+            else
+            {
+                TerrainAreaMaterialNotificationBus::Broadcast(
+                    &TerrainAreaMaterialNotificationBus::Events::OnTerrainSurfaceMaterialMappingChanged, GetEntityId(),
+                    surfaceMaterialMapping.m_surfaceTag,
+                    surfaceMaterialMapping.m_materialInstance);
+            }
+        }
+
+        if (!anyMaterialWasAlreadyActive && anyMaterialIsActive)
+        {
+            // Cache the current shape bounds.
+            LmbrCentral::ShapeComponentRequestsBus::EventResult(
+                m_cachedAabb, GetEntityId(), &LmbrCentral::ShapeComponentRequestsBus::Events::GetEncompassingAabb);
+
+            // Start listening for data requests.
+            TerrainAreaMaterialRequestBus::Handler::BusConnect(GetEntityId());
+
+            // Start listening for shape changes.
+            LmbrCentral::ShapeComponentNotificationsBus::Handler::BusConnect(GetEntityId());
+
+        }
+        else if (anyMaterialWasAlreadyActive && !anyMaterialIsActive)
+        {
+            // All materials have been deactivated, stop listening for requests and notifications.
+            m_cachedAabb = AZ::Aabb::CreateNull();
+            LmbrCentral::ShapeComponentNotificationsBus::Handler::BusDisconnect();
+            TerrainAreaMaterialRequestBus::Handler::BusConnect(GetEntityId());
+        }
+    }
+
+    bool TerrainSurfaceMaterialsListComponent::ReadInConfig(const AZ::ComponentConfig* baseConfig)
+    {
+        if (auto config = azrtti_cast<const TerrainSurfaceMaterialsListConfig*>(baseConfig))
+        {
+            m_configuration = *config;
+            return true;
+        }
+        return false;
+    }
+
+    bool TerrainSurfaceMaterialsListComponent::WriteOutConfig(AZ::ComponentConfig* outBaseConfig) const
+    {
+        if (auto config = azrtti_cast<TerrainSurfaceMaterialsListConfig*>(outBaseConfig))
+        {
+            *config = m_configuration;
+            return true;
+        }
+        return false;
+    }
+
+    void TerrainSurfaceMaterialsListComponent::OnShapeChanged([[maybe_unused]] ShapeComponentNotifications::ShapeChangeReasons reasons)
+     {
+         AZ::Aabb oldAabb = m_cachedAabb;
+
+         LmbrCentral::ShapeComponentRequestsBus::EventResult(
+             m_cachedAabb, GetEntityId(), &LmbrCentral::ShapeComponentRequestsBus::Events::GetEncompassingAabb);
+
+         TerrainAreaMaterialNotificationBus::Broadcast(
+             &TerrainAreaMaterialNotificationBus::Events::OnTerrainSurfaceMaterialMappingRegionChanged, GetEntityId(), oldAabb,
+             m_cachedAabb);
+     }
+
+    const AZStd::vector<TerrainSurfaceMaterialMapping>& TerrainSurfaceMaterialsListComponent::GetSurfaceMaterialMappings(
+         AZ::Aabb& region) const
+    {
+        region = m_cachedAabb;
+
+        return m_configuration.m_surfaceMaterials;
+    }
+
+    void TerrainSurfaceMaterialsListComponent::OnAssetReady(AZ::Data::Asset<AZ::Data::AssetData> asset)
+    {
+        // Find the missing material instance with the correct id.
+        for (auto& surfaceMaterialMapping : m_configuration.m_surfaceMaterials)
+        {
+            if (surfaceMaterialMapping.m_materialAsset.GetId() == asset.GetId() &&
+                (!surfaceMaterialMapping.m_materialInstance ||
+                    surfaceMaterialMapping.m_materialInstance->GetAssetId() != surfaceMaterialMapping.m_materialAsset.GetId()))
+            {
+                surfaceMaterialMapping.m_materialInstance = AZ::RPI::Material::FindOrCreate(surfaceMaterialMapping.m_materialAsset);
+                surfaceMaterialMapping.m_materialAsset.Release();
+            }
+        }
+        HandleMaterialStateChanges();
+    }
+
+    void TerrainSurfaceMaterialsListComponent::OnAssetReloaded(AZ::Data::Asset<AZ::Data::AssetData> asset)
+    {
+        OnAssetReady(asset);
+    }
+} // namespace Terrain
@@ -0,0 +1,101 @@
+/*
+ * 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
+ *
+ */
+
+#pragma once
+
+#include <Atom/Feature/Material/MaterialAssignment.h>
+#include <Atom/RPI.Reflect/Material/MaterialAsset.h>
+#include <AtomLyIntegration/CommonFeatures/Material/EditorMaterialSystemComponentRequestBus.h>
+#include <AzCore/Asset/AssetCommon.h>
+#include <AzCore/Component/Component.h>
+#include <LmbrCentral/Shape/ShapeComponentBus.h>
+#include <SurfaceData/SurfaceDataTypes.h>
+#include <TerrainRenderer/TerrainAreaMaterialRequestBus.h>
+
+
+namespace LmbrCentral
+{
+    template<typename, typename>
+    class EditorWrappedComponentBase;
+}
+
+namespace Terrain
+{
+    struct TerrainSurfaceMaterialMapping final
+    {
+    public:
+        AZ_CLASS_ALLOCATOR(TerrainSurfaceMaterialMapping, AZ::SystemAllocator, 0);
+        AZ_RTTI(TerrainSurfaceMaterialMapping, "{37D2A586-CDDD-4FB7-A7D6-0B4CC575AB8C}");
+        static void Reflect(AZ::ReflectContext* context);
+
+        SurfaceData::SurfaceTag m_surfaceTag;
+        AZ::Data::AssetId m_activeMaterialAssetId;
+        AZ::Data::Asset<AZ::RPI::MaterialAsset> m_materialAsset;
+        AZ::Data::Instance<AZ::RPI::Material> m_materialInstance;
+
+        bool m_active = false;
+    };
+
+    class TerrainSurfaceMaterialsListConfig : public AZ::ComponentConfig
+    {
+    public:
+        AZ_CLASS_ALLOCATOR(TerrainSurfaceMaterialsListConfig, AZ::SystemAllocator, 0);
+        AZ_RTTI(TerrainSurfaceMaterialsListConfig, "{68A1CB1B-C835-4C3A-8D1C-08692E07711A}", AZ::ComponentConfig);
+        static void Reflect(AZ::ReflectContext* context);
+
+        AZStd::vector<TerrainSurfaceMaterialMapping> m_surfaceMaterials;
+    };
+
+    class TerrainSurfaceMaterialsListComponent
+        : public AZ::Component
+        , private TerrainAreaMaterialRequestBus::Handler
+        , private AZ::Data::AssetBus::Handler
+        , private LmbrCentral::ShapeComponentNotificationsBus::Handler
+    {
+    public:
+        template<typename, typename>
+        friend class LmbrCentral::EditorWrappedComponentBase;
+        AZ_COMPONENT(TerrainSurfaceMaterialsListComponent, "{93CF3938-FBC3-4E55-B825-27BA94A5CD35}");
+        static void GetProvidedServices(AZ::ComponentDescriptor::DependencyArrayType& services);
+        static void GetIncompatibleServices(AZ::ComponentDescriptor::DependencyArrayType& services);
+        static void GetRequiredServices(AZ::ComponentDescriptor::DependencyArrayType& services);
+        static void Reflect(AZ::ReflectContext* context);
+
+        TerrainSurfaceMaterialsListComponent(const TerrainSurfaceMaterialsListConfig& configuration);
+        TerrainSurfaceMaterialsListComponent() = default;
+        ~TerrainSurfaceMaterialsListComponent() = default;
+
+        //////////////////////////////////////////////////////////////////////////
+        // AZ::Component interface implementation
+        void Activate() override;
+        void Deactivate() override;
+        bool ReadInConfig(const AZ::ComponentConfig* baseConfig) override;
+        bool WriteOutConfig(AZ::ComponentConfig* outBaseConfig) const override;
+
+    private:
+        void HandleMaterialStateChanges();
+        int CountMaterialIDInstances(AZ::Data::AssetId id) const;
+
+        ////////////////////////////////////////////////////////////////////////
+        // ShapeComponentNotificationsBus
+        void OnShapeChanged(ShapeComponentNotifications::ShapeChangeReasons reasons) override;
+
+        //////////////////////////////////////////////////////////////////////////
+        // TerrainAreaMaterialRequestBus
+        const AZStd::vector<TerrainSurfaceMaterialMapping>& GetSurfaceMaterialMappings(AZ::Aabb& region) const override;
+
+        //////////////////////////////////////////////////////////////////////////
+        // AZ::Data::AssetBus::Handler
+        void OnAssetReady(AZ::Data::Asset<AZ::Data::AssetData> asset) override;
+        void OnAssetReloaded(AZ::Data::Asset<AZ::Data::AssetData> asset) override;
+
+        TerrainSurfaceMaterialsListConfig m_configuration;
+
+        AZ::Aabb m_cachedAabb;
+    };
+} // namespace Terrain
@@ -0,0 +1,22 @@
+/*
+ * 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 <TerrainRenderer/EditorComponents/EditorTerrainSurfaceMaterialsListComponent.h>
+#include <AzCore/Serialization/SerializeContext.h>
+#include <AzCore/Serialization/EditContext.h>
+
+namespace Terrain
+{
+    void EditorTerrainSurfaceMaterialsListComponent::Reflect(AZ::ReflectContext* context)
+    {
+        BaseClassType::ReflectSubClass<EditorTerrainSurfaceMaterialsListComponent, BaseClassType>(context, 1,
+            &LmbrCentral::EditorWrappedComponentBaseVersionConverter<typename BaseClassType::WrappedComponentType,
+            typename BaseClassType::WrappedConfigType, 1>
+        );
+    }
+}
@@ -0,0 +1,32 @@
+/*
+ * 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
+ *
+ */
+
+#pragma once
+
+#include <TerrainRenderer/Components/TerrainSurfaceMaterialsListComponent.h>
+#include <AzToolsFramework/ToolsComponents/EditorComponentBase.h>
+#include <LmbrCentral/Component/EditorWrappedComponentBase.h>
+
+namespace Terrain
+{
+    class EditorTerrainSurfaceMaterialsListComponent
+        : public LmbrCentral::EditorWrappedComponentBase<TerrainSurfaceMaterialsListComponent, TerrainSurfaceMaterialsListConfig>
+    {
+    public:
+        using BaseClassType = LmbrCentral::EditorWrappedComponentBase<TerrainSurfaceMaterialsListComponent, TerrainSurfaceMaterialsListConfig>;
+        AZ_EDITOR_COMPONENT(EditorTerrainSurfaceMaterialsListComponent, "{335CDED5-2E76-4342-8675-A60F66C471BF}", BaseClassType);
+        static void Reflect(AZ::ReflectContext* context);
+
+        static constexpr const char* const s_categoryName = "Terrain";
+        static constexpr const char* const s_componentName = "Terrain Surface Materials List";
+        static constexpr const char* const s_componentDescription = "Provides a mapping between surface tags and render materials.";
+        static constexpr const char* const s_icon = "Editor/Icons/Components/TerrainHeight.svg";
+        static constexpr const char* const s_viewportIcon = "Editor/Icons/Components/Viewport/TerrainHeight.svg";
+        static constexpr const char* const s_helpUrl = "";
+    };
+}
@@ -0,0 +1,77 @@
+/*
+ * 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
+ *
+ */
+
+#pragma once
+
+#include <AzCore/Component/ComponentBus.h>
+
+#include <SurfaceData/SurfaceDataTypes.h>
+
+#include <Atom/RPI.Public/Material/Material.h>
+
+#include <TerrainRenderer/Components/TerrainSurfaceMaterialsListComponent.h>
+
+namespace Terrain
+{
+    //! This bus provides retrieval of information from Terrain Surfaces.
+    class TerrainAreaMaterialRequests
+        : public AZ::ComponentBus
+    {
+    public:
+        ////////////////////////////////////////////////////////////////////////
+        // EBusTraits
+        using MutexType = AZStd::recursive_mutex;
+        ////////////////////////////////////////////////////////////////////////
+
+        virtual ~TerrainAreaMaterialRequests() = default;
+
+        //! Get the Material asset assigned to a particular surface tag.
+        virtual const AZStd::vector<struct TerrainSurfaceMaterialMapping>& GetSurfaceMaterialMappings(AZ::Aabb& region) const = 0;
+    };
+
+    using TerrainAreaMaterialRequestBus = AZ::EBus<TerrainAreaMaterialRequests>;
+
+     //! Notifications for when the surface -> material mapping changes..
+    class TerrainAreaMaterialNotifications : public AZ::EBusTraits
+    {
+    public:
+        //////////////////////////////////////////////////////////////////////////
+        // EBusTraits overrides
+        static const AZ::EBusHandlerPolicy HandlerPolicy = AZ::EBusHandlerPolicy::Multiple;
+        static const AZ::EBusAddressPolicy AddressPolicy = AZ::EBusAddressPolicy::Single;
+        //////////////////////////////////////////////////////////////////////////
+
+        virtual void OnTerrainSurfaceMaterialMappingCreated(
+            [[maybe_unused]] AZ::EntityId entityId,
+            [[maybe_unused]] SurfaceData::SurfaceTag surface,
+            [[maybe_unused]] AZ::Data::Instance<AZ::RPI::Material> material)
+        {
+        }
+
+        virtual void OnTerrainSurfaceMaterialMappingDestroyed(
+            [[maybe_unused]] AZ::EntityId entityId,
+            [[maybe_unused]] SurfaceData::SurfaceTag surface)
+        {
+        }
+
+        virtual void OnTerrainSurfaceMaterialMappingChanged(
+            [[maybe_unused]] AZ::EntityId entityId,
+            [[maybe_unused]] SurfaceData::SurfaceTag surface,
+            [[maybe_unused]] AZ::Data::Instance<AZ::RPI::Material> material)
+        {
+        }
+
+        virtual void OnTerrainSurfaceMaterialMappingRegionChanged(
+            [[maybe_unused]] AZ::EntityId entityId,
+            [[maybe_unused]] const AZ::Aabb& oldRegion,
+            [[maybe_unused]] const AZ::Aabb& newRegion)
+        {
+        }
+    };
+    using TerrainAreaMaterialNotificationBus = AZ::EBus<TerrainAreaMaterialNotifications>;
+} // namespace Terrain
@@ -0,0 +1,90 @@
+/*
+ * 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 <AzTest/AzTest.h>
+#include <AzCore/Component/ComponentApplication.h>
+#include <TerrainRenderer/Components/TerrainSurfaceMaterialsListComponent.h>
+#include <MockAxisAlignedBoxShapeComponent.h>
+
+using ::testing::NiceMock;
+using ::testing::AtLeast;
+using ::testing::_;
+
+namespace UnitTest
+{
+    class TerrainSurfaceMaterialsListTest : public ::testing::Test
+    {
+    protected:
+        AZ::ComponentApplication m_app;
+
+        void SetUp() override
+        {
+            AZ::ComponentApplication::Descriptor appDesc;
+            appDesc.m_memoryBlocksByteSize = 20 * 1024 * 1024;
+            appDesc.m_recordingMode = AZ::Debug::AllocationRecords::RECORD_NO_RECORDS;
+            appDesc.m_stackRecordLevels = 20;
+
+            m_app.Create(appDesc);
+        }
+
+        AZStd::unique_ptr<AZ::Entity> CreateEntity()
+        {
+            auto entity = AZStd::make_unique<AZ::Entity>();
+            entity->Init();
+            return entity;
+        }
+
+        AZStd::unique_ptr<AZ::Entity> CreateEntityWithShapeComponents()
+        {
+            auto entity = CreateEntity();
+
+            auto shapeComponent = entity->CreateComponent<UnitTest::MockAxisAlignedBoxShapeComponent>();
+            m_app.RegisterComponentDescriptor(shapeComponent->CreateDescriptor());
+
+            return entity;
+        }
+
+        Terrain::TerrainSurfaceMaterialsListComponent* AddSurfaceMaterialListComponent(AZ::Entity* entity)
+        {
+            auto surfaceMaterialsListComponent = entity->CreateComponent<Terrain::TerrainSurfaceMaterialsListComponent>();
+            m_app.RegisterComponentDescriptor(surfaceMaterialsListComponent->CreateDescriptor());
+
+            return surfaceMaterialsListComponent;
+        }
+
+        void TearDown() override
+        {
+            m_app.Destroy();
+        }
+    };
+
+    TEST_F(TerrainSurfaceMaterialsListTest, SurfaceGradientListRequiresShapeToActivate)
+    {
+        auto entity = CreateEntity();
+
+        AddSurfaceMaterialListComponent(entity.get());
+
+        const AZ::Entity::DependencySortOutcome sortOutcome = entity->EvaluateDependenciesGetDetails();
+        EXPECT_FALSE(sortOutcome.IsSuccess());
+
+        entity.reset();
+    }
+
+    TEST_F(TerrainSurfaceMaterialsListTest, SurfaceGradientListActivatesSuccessfully)
+    {
+        auto entity = CreateEntityWithShapeComponents();
+
+        AddSurfaceMaterialListComponent(entity.get());
+
+        entity->Activate();
+
+        EXPECT_EQ(entity->GetState(), AZ::Entity::State::Active);
+                
+        entity.reset();
+    }
+} // namespace UnitTest
@@ -25,6 +25,8 @@ set(FILES
    Source/EditorTerrainModule.h
    Source/TerrainModule.cpp
    Source/TerrainModule.h
+    Source/TerrainRenderer/EditorComponents/EditorTerrainSurfaceMaterialsListComponent.cpp
+    Source/TerrainRenderer/EditorComponents/EditorTerrainSurfaceMaterialsListComponent.h
    Source/TerrainRenderer/EditorComponents/EditorTerrainMacroMaterialComponent.cpp
    Source/TerrainRenderer/EditorComponents/EditorTerrainMacroMaterialComponent.h
 )
@@ -24,10 +24,13 @@ set(FILES
    Source/Components/TerrainWorldDebuggerComponent.h
    Source/Components/TerrainWorldRendererComponent.cpp
    Source/Components/TerrainWorldRendererComponent.h
+    Source/TerrainRenderer/Components/TerrainSurfaceMaterialsListComponent.cpp
+    Source/TerrainRenderer/Components/TerrainSurfaceMaterialsListComponent.h
    Source/TerrainRenderer/Components/TerrainMacroMaterialComponent.cpp
    Source/TerrainRenderer/Components/TerrainMacroMaterialComponent.h
    Source/TerrainRenderer/TerrainFeatureProcessor.cpp
    Source/TerrainRenderer/TerrainFeatureProcessor.h
+    Source/TerrainRenderer/TerrainAreaMaterialRequestBus.h
    Source/TerrainRenderer/TerrainMacroMaterialBus.h
    Source/TerrainSystem/TerrainSystem.cpp
    Source/TerrainSystem/TerrainSystem.h
@@ -10,5 +10,6 @@ set(FILES
    Tests/TerrainTest.cpp
    Tests/TerrainSystemTest.cpp
    Tests/LayerSpawnerTests.cpp
+    Tests/SurfaceMaterialsListTest.cpp
    Tests/MockAxisAlignedBoxShapeComponent.h
 )