UMaterialInstanceDynamic.md

2020-08-11_13:53:57

UMaterialInstanceDynamic

A Dynamic Material Instance (UMaterialInstanceDynamic) is one where the parameters can be changed during Play. The alternative is a Constant Material Instance (UMaterialInstanceConstant), which can only have its parameters changed from the Editor.

https://answers.unrealengine.com/questions/560119/setting-material-and-material-instance-in-c-withou.html

// MyActor.h:
#include  "GameFramework/Actor.h"
#include  "MyActor.generated.h"

UCLASS()
class  MATTEST_API AMyActor : public  AActor
{
    GENERATED_BODY()
public:
    AMyActor();
public:
    UStaticMeshComponent* MeshComp;
    UMaterial* StoredMaterial;
    UMaterialInstanceDynamic* DynamicMaterialInst;
};

// MyActor.cpp:
#include  "MatTest.h"
#include  "MyActor.h"

AMyActor::AMyActor()
{
    PrimaryActorTick.bCanEverTick = true;
    MeshComp = CreateDefaultSubobject<UStaticMeshComponent>(
        TEXT("Mesh"));

    static  ConstructorHelpers::FObjectFinder<UStaticMesh> FoundMesh(
        TEXT("/Engine/EditorMeshes/EditorSphere.EditorSphere"));
    if (FoundMesh.Succeeded())
    {
        MeshComp->SetStaticMesh(FoundMesh.Object);
    }

    static  ConstructorHelpers::FObjectFinder<UMaterial> FoundMaterial(
        TEXT("/Engine/EditorMaterials/BasicMeshes/M_Floor.M_Floor"));
    if (FoundMaterial.Succeeded())
    {
        StoredMaterial = FoundMaterial.Object;
    }

    DynamicMaterialInst = UMaterialInstanceDynamic::Create(
        StoredMaterial, MeshComp);
    MeshComp->SetMaterial(0, DynamicMaterialInst);
}

A Dynamic Material is created from a parent Material already set on a StaticMesh with

DynamicMaterial = GetMesh()->CreateDynamicMaterialInstance(0);
if (DynamicMaterial)
{
    DynamicMaterial->SetScalarParameterValue(TEXT("base opacity"), 1);
}

At least I think the type of DynamicMaterial here is UMaterialInstanceDynamic.

[[2020-05-10_11:01:04]] Materials
[[2021-05-06_08:51:54]] UMaterial
[[2020-08-11_11:13:52]] UMaterialInstance
[[2020-08-11_13:53:42]] UMaterialInstanceConstant