【UE4】读写 Texture 数据

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mob604756ff98d6 2021-10-22 13:24:00

文章标签 Unreal Engine ide 2d 数据贴图 文章分类 运维

创建texture

方式一

void AActor_Assignment2::TextureFromImage_Internal( const TArray<FColor>& SrcData, const bool UseAlpha)
{
  const int32 SrcWidth = CanvasSize.X;
  const int32 SrcHeight = CanvasSize.Y;
  // Create the texture
  T_Result = UTexture2D::CreateTransient(CanvasSize.X, CanvasSize.Y, PF_B8G8R8A8);

  // Lock the texture so it can be modified
  uint8* MipData = static_cast<uint8*>(T_Result->PlatformData->Mips[0].BulkData.Lock(LOCK_READ_WRITE));

  // Create base mip.
  uint8* DestPtr = NULL;
  const FColor* SrcPtr = NULL;
  for (int32 y = 0; y < SrcHeight; y++)
  {
    DestPtr = &MipData[(SrcHeight - 1 - y) * SrcWidth * sizeof(FColor)];
    SrcPtr = const_cast<FColor*>(&SrcData[(SrcHeight - 1 - y) * SrcWidth]);
    for (int32 x = 0; x < SrcWidth; x++)
    {
      *DestPtr++ = SrcPtr->B;
      *DestPtr++ = SrcPtr->G;
      *DestPtr++ = SrcPtr->R;
      if (UseAlpha)
      {
        *DestPtr++ = SrcPtr->A;
      }
      else
      {
        *DestPtr++ = 0xFF;
      }
      SrcPtr++;
    }
  }

  // Unlock the texture
  T_Result->PlatformData->Mips[0].BulkData.Unlock();
  T_Result->UpdateResource();

}

方式二

void AActor_Assignment3::BeginPlay()
{
  Super::BeginPlay();

  VideoTextureColor = UTexture2D::CreateTransient(640, 480, PF_B8G8R8A8);
  VideoTextureColor->UpdateResource();
  FUpdateTextureRegion2D* RegionColor = new FUpdateTextureRegion2D(0, 0, 0, 0, 640, 480);
  //FUpdateTextureRegionData* ColorRegionData = new FUpdateTextureRegionsData;

  // Populate the texture with blue color
  TArray<FColor> PixelDepthData;
  PixelDepthData.Init(FColor(255, 255, 0, 255), 640 * 480);


  VideoTextureColor->UpdateTextureRegions(
    (int32)0,
    (uint32)1,
    RegionColor,
    (uint32)(4 * 640),
    (uint32)4,
    (uint8*)PixelDepthData.GetData()
  );
   VideoTextureColor->LODGroup = TEXTUREGROUP_Pixels2D;

}

访问Texture数据

方式一

  VideoTextureColor->CompressionSettings = TextureCompressionSettings::TC_VectorDisplacementmap;
  VideoTextureColor->MipGenSettings = TextureMipGenSettings::TMGS_NoMipmaps;
  VideoTextureColor->SRGB = false;  //确保这些设置，否则颜色容易丢失
  //VideoTextureColor->LODGroup = TEXTUREGROUP_Pixels2D;
  VideoTextureColor->UpdateResource();

  FTexture2DMipMap& Mip = VideoTextureColor->PlatformData->Mips[0];
  uint8* Data = (uint8*)Mip.BulkData.Lock(LOCK_READ_ONLY);
  // read here in low level:
  //let's say I want pixel x = 300, y = 23
  //basic formula, data[channels * (width * y + x)];
  FColor pixelColor = FColor(0, 0, 0, 255);
  int x = 200, y = 2;
  pixelColor.B = Data[4 * (640 * y + x) + 0];
  pixelColor.G = Data[4 * (640 * y + x) + 1];
  pixelColor.R = Data[4 * (640 * y + x) + 2];
  pixelColor.A = 255;

  Mip.BulkData.Unlock();
  VideoTextureColor->UpdateResource();
  UKismetSystemLibrary::PrintString(GetWorld(), TEXT("font color"), true, true, pixelColor);