VTK（Activiz 5.8.0）纹理影响不透明度

Question

When I try to render a scene that contains a transparent object (50% transparency) and a textured opaque object, the transparent object becomes more faded. If the textured object is hidden, the transparent object gets its expected transparency again.

I map the texture to the object using a vtkTextureMapToSphere . Note that bounds in the code below represents the bounding box of the _polydata object to which I apply the texture.

vtkTextureMapToSphere textureMapper = vtkTextureMapToSphere.New();
textureMapper.SetInput(_polydata);
textureMapper.SetCenter(bounds.center[0], bounds.center[1], bounds.center[2]);
textureMapper.PreventSeamOn();

vtkTransformTextureCoords transformMap = vtkTransformTextureCoords.New();
double factorEnlarge = 4;
double scale = bounds.dimensions.Sum() / bounds.dimensions.Length / factorEnlarge;
transformMap.SetInputConnection(textureMapper.GetOutputPort());
transformMap.SetScale(scale, scale, scale);

vtkPolyDataMapper mapper = vtkPolyDataMapper.New();
mapper.SetInputConnection(transformMap.GetOutputPort());

vtkActor actor = vtkActor.New();
actor.SetTexture(texture);
actor.GetProperty().SetColor((double)color.R / 255, (double)color.G / 255, (double)color.B / 255);
actor.GetProperty().SetOpacity(alpha);
actor.SetMapper(mapper);
actor.GetProperty().SetInterpolationToPhong();

renderer.AddActor(actor);

EDIT

After turning the PreventSeam option of vtkTextureMapToSphere off, the difference in color has disappeared. However, there still is a noticeable difference in shading wherever you view through more than two surfaces of the mesh (eg where there are cavities in the mesh).

Answer 1

Well if I understand the current state of the question You are asking how to remove the darker colors caused by pockets in your mesh. If that's correct you simply need to figure out how to activate occlusion culling for your partly transparent mesh. Unfortunately I'm not familiar with Activiz so i can't help with the details but in XNA (DirectX) you would either need to change the GraphicsDevice.BlendState or create a custom shader depending on what your end goals were.

I realize it's not much but i hope it helps.