Shadow Generations Shaders - DirectionBlend dpnndpn

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Overview

Shader Behavior Overview

Shader model:

   [2] Standard (PBR)
Does not support:

• Transparent mesh layer
• Noise

An advanced PBR shader that uses

• directional blending to interpolate between two texture sets
• distance blending to blend a detail normal map into the first normal texture

Warning

This shader has a bug where the second normal texture is not applied. It is advised to not used this shader.

Related shaders

• Blend_dpnbdpn
• Blend_dpndpn
• BlendDetail_dndnd
• BlendDetail_dpndpnn
• Detail_dpndpn
• Detail_dpnn
• DirectionBlend_dpndpn
• DirectionBlend_dpndpnn
• DistanceBlend_dpn

Behavior

Distance blending

Uses distance blending to interpolate

• from the normal texture
• to the normal and normal[1] textures blended together

for the normal map of the first set of textures.

The shader uses detailDistance and detailFadeRange from the stage RFL to determine the detail range.

Directional blending

This shader has two sets of PBR textures:

• diffuse, specular and normal
• diffuse[1], specular[1] and normal[2]

The shader uses a blend factor to interpolate from the first set of textures to second one.
This blend factor is calculated using directional blending.

This involves various inputs:

Input	Description
Normal map	The normal (afterdistance blending) texture is applied to the normal direction before calculating the directional blend factor
Red vertex color channel	The directional blend bias
DirectionParam parameter	The directional blend direction
NormalBlendParam parameter	The Directional blend intensity and offset
diffuse and diffuse[1] (multiplied together)	The Directional blend limit

Transparency

(For some reason) the directional blend factor is used for the transparency, and not any of the diffuse textures alpha channels, which makes for limited use cases.

Vertex Colors

• The colors...
  • Red channel is used as the directional blend bias
  • Green and blue channels are unused
• Alpha is unused

Bugs

Warning

When the shader unpacks the normal[2] texture, the tangent and binormal vectors are left at 0, which results in no change by the normal map at all.

Speculation:

The developers could have attempted to implement multi-tangent here, but must have compiled the shader before the multi-tangent system was properly implemented, which left the tangent and binormal at 0 and resulted in incorrectly unpacking the normal map.

Material Inputs

Textures

Name	Index	UV Index	Kind	Red	Green	Blue	Alpha
diffuse	0	Any	Albedo	First Albedo color			directional blend limit
diffuse	1	Any	Albedo	Second Albedo color			directional blend limit
specular	0	Any	PRM	First Specular factor; Gets multiplied by 0.25	First Smoothness factor	First Metallic factor	First Ambient Occlusion
specular	1	Any	PRM	Second Specular factor; Gets multiplied by 0.25	Second Smoothness factor	Second Metallic factor	Second Ambient Occlusion
normal	0	Any	Normal map	First Normal map direction		N/A	N/A
normal	1	Any	Detail Normal map	Detail Normal map direction		N/A	N/A
normal	2	Any	Normal map	Second Normal map direction		N/A	N/A

Parameters

Name	X	Y	Z	W
DetailFactor	UV scale for the normal[1] texture	N/A	N/A	N/A
DirectionParam	Directional blend direction			N/A
NormalBlendParam	Directional blend intensity	Directional blend offset	N/A	N/A

Technical

For some reason using the IBL_CAPTURE debug view the directional blend factor is set to 0. Why this was done is unknown, and makes no sense.

Shader Features
is_compute_instancing
is_use_tex_srt_anim
enable_alpha_threshold
is_use_gi_prt
is_use_gi_sg
is_use_gi