The Sampler texture is a utility for building shader networks. It is capable of extracting a variety of information for each point on a surface.

The Sampler texture provides information about various aspects of the shaded points such as position, normal, bump normal, reflection/refraction vectors and UVW coordinates. It can be used either for world position passes or normal passes. It also extracts information about the scene, converting the gathered information into RGB data for use in compositing.

It can be also used to drive a material channel to achieve various effects. This can provide more render passes with information that can allow more possibilities to editing during the compositing process.

Although the TexSampler node does not contain any inputs, it provides a wide variety of outputs.

point – The sampled point.

pointReference – The shading point in reference space. 

pointObject/Camera – The sampled point in object/camera space.

normal – The surface normal for the sampled point.

normalReferece – The smooth normal in reference space. 

normalCamera/Object – The surface normal for the sampled point in object/camera space.

bumpNormal – The bump normal for the sampled point.

bumpNormalCamera/Object – The bump normal for the sampled point in object/camera space.

gnormal – The geometric normal for the sampled point.

camToWorld – The transformation from camera to world space.

view_dir – The view direction.

frame_time – The current frame (image) time. 

ray_time – The ray time between the motion blur interval. 

facing_ratio – Returns a number between 0 and 1 that specifies if the sampled point is facing towards or away from the camera.

material_id – The material ID for the sampled point.

flipped_normal – Specifies which side of the surface is sampled.

cameraNearClipPlane – The camera near clipping plane, calculated from the scene bounding box and the camera transform in the frame data. 

cameraFarClipPlane – The camera far clipping plane, calculated from the scene bounding box and the camera transform in the frame data. 

uvCoord – The UV coordinates for the sampled point.

rayDirection – Returns a vector from the sampled point to the camera position.

pixelCenter – The location of the pixel in the final rendered image that corresponds to the sampled point.

tangentUCamera – The surface tangent in the U direction for the sampled point.

tangentVCamera – The surface tangent in the V direction for the sampled point.

ray_depth – The ray depth. 

path_length – The path length. 

object_id – Returns the object ID for the object at the sampled point.

parent_object_id – Returns the object ID for the parent object of the sampled point.

velocity – The velocity of the sampled point.

speed – The speed of the sampled point.

random_by_renderID – Allows random colors or textures to be assigned to several objects according to each object's render ID.

random_by_polyShell – Allows random color or textures to be assigned to multiple polygon shells that have been combined into a single object.

random_by_scene_name – Returns a random value for each geometry node.

face_index – The index of each individual face.

barycentric_coords – (also known as areal coordinates) Indicates that the coordinates u, v and w are proportional to the area of the three sub-triangles defined by P, the point located on the triangle, and the triangle's vertices (A, B, C).

tangentUWorld – The U axis of the currently shaded point's UVW space, transformed in world space.

tangentVWorld – The V axis of the currently shaded point's UVW space, transformed in world space.

UV Name – Specifies the name of the UV channel that is used for sampling.

UV Index – Specifies the index of the UV channel that should be used for sampling when there is no applicable UV set name.

Reference Vertex Attribute – Attribute name to consider for 'pointReference' output.

Reference Normal Attribute – Attribute name to consider for 'normalReference' output.