UUSL Semantics

Vertex Shader Semantics

Vertex shader semantics contain necessary input and output data for shader. You should initialize variables first and then use them.

UUSL	OpenGL	Direct3D	Description
INIT_ATTRIBUTE(TYPE,NUM,SEMANTICS)	in TYPE s_attribute_ ## NUM;	TYPE attribute_ ## NUM : SEMANTICS;	Adds a semantic to a vertex shader variable.
INIT_OUT(TYPE,NUM)	out TYPE s_texcoord_ ## NUM;	TYPE data_ ## NUM : TEXCOORD ## NUM;	Adds an output data semantic.
INIT_POSITION	-	float4 position : SV_POSITION;	Adds a position system-value semantic.
INIT_INSTANCE	-	uint instance : SV_INSTANCEID;	Adds a per-instance identifier system-value semantic.

Here is an example of vertex shader input and output structures:

UUSL

// Input vertex data
STRUCT(VERTEX_IN)
	INIT_ATTRIBUTE(float4,0,POSITION)	// Vertex position
	INIT_ATTRIBUTE(float4,1,TEXCOORD0)	// Vertex texcoord (uv)
	INIT_ATTRIBUTE(float4,2,TEXCOORD1)	// Vertex basis tangent
	INIT_ATTRIBUTE(float4,3,TEXCOORD2)	// Vertex color
END

// Our output vertex data
STRUCT(VERTEX_OUT)
	INIT_POSITION		// Out projected position
	INIT_OUT(float4,0)	// Texcoord (uv)
	INIT_OUT(float3,1)	// Vertex direction
END

Warning
					You should add a new line (press Enter) after closing the instruction.
				

Use the following pre-defined variables to use the input\output vertex shader semantics:

UUSL	OpenGL	Direct3D	Description
IN_INSTANCE	gl_InstanceID	input.instance	An input per-instance identifier system-value variable.
IN_ATTRIBUTE(NUM)	s_attribute_ ## NUM	input.attribute_ ## NUM	An input shader variable.
OUT_DATA(NUM)	s_texcoord_ ## NUM	output.data_ ## NUM	An output texture coordinates variable.
OUT_POSITION	gl_Position	output.position	An output position system-value variable.

Fragment Shader Semantics

Fragment shader semantics contain necessary input and output data for shader. You should initialize variables first and then use them.

UUSL	OpenGL	Direct3D	Description
INIT_IN(TYPE,NUM)	in TYPE s_texcoord_ ## NUM;	TYPE data_ ## NUM : TEXCOORD ## NUM;	Adds an input texture coordinates semantic.
INIT_COLOR(TYPE)	out TYPE s_frag_color;	TYPE color : SV_TARGET;	Add an output diffuse or specular color semantic (single RT).
INIT_DEPTH	-	float depth : SV_DEPTH;	Add an output depth system-value semantic.
INIT_MRT(TYPE,NUM)	out TYPE s_frag_data_ ## NUM;	TYPE color_ ## NUM : SV_TARGET ## NUM;	Add an output color system-value semantic (some RTs).
INIT_FRONTFACE	---	bool frontface : SV_ISFRONTFACE;	Adds an input semantic indicates primitive face (frontface or not).

To use the variables in the code, use the following variables:

UUSL	OpenGL	Direct3D	Description
IN_POSITION	gl_FragCoord	input.position	An input position value.
IN_DATA(NUM)	s_texcoord_ ## NUM	input.data_ ## NUM	An input texture coordinates variable.
IN_FRONTFACE	!gl_FrontFacing	input.frontface	Floating-point scalar that indicates a back-facing primitive. A negative value faces backwards, while a positive value faces the camera.
OUT_COLOR	s_frag_color	output.color	An output color value (single RT).
OUT_DEPTH	gl_FragDepth	output.depth	An output depth value.
OUT_MRT(NUM)	out TYPE s_frag_data_ ## NUM;	output.color_ ## NUM	An output color value for MRTs.

Here is a simple example of using the variable in the main function of the shader:

USUL

MAIN_BEGIN(FRAGMENT_OUT,FRAGMENT_IN)
	
	float4 texcoord = IN_DATA(0);

	/* ... other code ... */
END

Warning
				You should add a new line (press Enter) after closing the instruction.
			

Geometry Shader Semantics

UUSL	OpenGL	Direct3D	Description
INIT_GEOM_IN(TYPE,NUM)	in TYPE s_geom_texcoord_ ## NUM[];	TYPE data_ ## NUM : TEXCOORD ## NUM;	Add an input texture coordinates semantic for the geometry-shader stage.
INIT_GEOM_OUT(TYPE,NUM)	out TYPE s_geom_texcoord_ ## NUM;	TYPE data_ ## NUM : TEXCOORD ## NUM;	Add an output texture coordinates semantic for the geometry-shader stage.

UUSL	OpenGL	Direct3D	Description
IN_GEOM_DATA(NUM,INDEX)	s_geom_texcoord_ ## NUM ## [INDEX]	input[INDEX].data_ ## NUM	An input texture coordinates value.
IN_GEOM_POSITION(INDEX)	gl_in[INDEX].gl_Position	input[INDEX].position	An input position value.
OUT_GEOM_DATA(NUM)	s_geom_texcoord_ ## NUM	output.data_ ## NUM	An output texture coordinates value.
TRIANGLE_IN	triangles	triangle	Input primitive type: triangle list or triangle strip.
TRIANGLE_OUT	triangle_strip	TriangleStream	Output primitive type: a sequence of triangle primitives
LINE_OUT	line_strip	LineStream	Output primitive type: a sequence of line primitives

Last update: 03.07.2017

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UUSL Semantics

In This Article:

Vertex Shader Semantics

Fragment Shader Semantics

Geometry Shader Semantics