Shaders

This type of node is used to describe a UUSL shader in an ULON-based material file. Currently, the engine supports Vertex, Control, Evaluate, Geometry, Fragment, and Compute shaders.

The syntax is the following:

Shader name =
#{
	// UUSL code
#}

As a node’s value you must specify a UUSL-based code enclosed in "#{" and "#}".

See the SDK/data/core/shaders/common/ directory for the list of headers implementing common shaders’ functions which can be included and used in custom shaders. To start writing UUSL shaders, include the common header:

#include <core/shaders/common/common.h>

The following types of shaders corresponding to their counterparts in different graphic APIs are available:

The shader node is usually used as a shader value for the Pass node.

Shader shader_a =
#{
	// some UUSL code
#}

Pass ambient
{
	Vertex = shader_a
	Fragment = shader_a
}

The advantages of this shader setup method are:

• It reduces the amount of identical code.
• One shader code can be used in different render passes.

On the other hand, it is not the best approach for large shaders. Use includes for these cases:

1. Write different shaders in separate files and then specify their paths as shader values in the pass:
   shaders/a.vert (UUSL)

   // some UUSL code

   shaders/b.frag (UUSL)

   // some UUSL code

   Source code (ULON)

   Pass deferred 
   {
   	Vertex = "shaders/a.vert"
   	Fragment = "shaders/b.frag"
   }

2. Include the code of a different shader by using the marker: #shader shader_name.
   Source code (ULON)

   Shader a = 
   #{
           // shader code A
   }#
   
   Shader b = 
   #{
           // shader code B
           #shader a
   }#
   
   // the result shader b will look like this: 
   Shader b = 
   #{
           // shader code B
           // shader code A
   #}