UUSL Keywords and Types
This documentation article contains information about keywords, data types, pre-defined variables, constants and other features of the UUSL. This information can be used as the reference document for writing shaders.
To start using UUSL, include the core/shaders/common/common.h file.
#include <core/shaders/common/common.h>
For fragment shader functions, use the core/shaders/common/fragment.h file.
Data Types
This articles contains different data types of UUSL.
UUSL | OpenGL | Direct3D | Description |
---|---|---|---|
int2 | ivec2 | int2 | A vector with two 32-bit signed integer components. |
int3 | ivec3 | int3 | A vector with three 32-bit signed integer components. |
int4 | ivec4 | int4 | A vector with four 32-bit signed integer components. |
uint2 | uvec4 | int2 | A vector with two 32-bit unsigned integer components. |
uint3 | uvec4 | uint3 | A vector with three 32-bit unsigned integer components. |
uint4 | uvec4 | uint4 | A vector with four 32-bit unsigned integer components. |
float | float | float | A 32-bit floating point value. |
float2 | vec2 | float2 | A vector with two 32-bit floating point value components. |
float3 | vec3 | float3 | A vector with three 32-bit floating point value components. |
float4 | vec4 | float4 | A vector with four 32-bit floating point value components. |
float2x2 | mat2 | float2x2 | A matrix with 2 rows, 2 column of 32-bit floating point value components. |
float3x3 | mat3 | float3x3 | A matrix with 3 rows, 3 column of 32-bit floating point value components. |
float4x4 | mat4 | float4x4 | A matrix with 4 rows, 4 column of 32-bit floating point value components. |
Use these variable aliases when working with textures to make your shader's code readable:
UUSL | OpenGL | Direct3D | Description |
---|---|---|---|
TYPE_R | float | float | A 32-bit floating point value. |
TYPE_RG | float2 | float2 | A vector with two 32-bit floating point value components. |
TYPE_RGB | float3 | float3 | A vector with three 32-bit floating point value components. |
TYPE_RGBA | float4 | float4 | A vector with four 32-bit floating point value components. |
UUSL | OpenGL | Direct3D | Description |
---|---|---|---|
FLOAT(X) | float(X) | X | Converts the value to float. |
FLOAT2(X) | vec2(X) | X | Converts the value to the two-component vector. |
FLOAT3(X) | vec3(X) | X | Converts the value to the three-component vector. |
FLOAT4(X) | vec4(X) | X | Converts the value to the four-component vector. |
INT(X) | int(X) | X | Converts the value to int. |
INT2(X) | int2(X) | X | Converts the value to the two component vector. |
INT3(X) | int3(X) | X | Converts the value to the three-component vector. |
INT4(X) | int4(X) | X | Converts the value to the three-component vector. |
BOOL2(X) | bvec2(X) | X | Converts the value to the two component boolean vector. |
BOOL3(X) | bvec3(X) | X | Converts the value to the three-component boolean vector. |
BOOL4(X) | bvec4(X) | X | Converts the value to the three-component boolean vector. |
Defined Values
UUSL | Value |
---|---|
float_isrgb | 2.233333f |
float4_zero | float4(0.0f,0.0f,0.0f,0.0f) |
float4_one | float4(1.0f,1.0f,1.0f,1.0f) |
float4_neg_one | float4(-1.0f,-1.0f,-1.0f,-1.0f) |
float4_isrgb | float4(float_isrgb,float_isrgb,float_isrgb,float_isrgb) |
float3_zero | float3(0.0f,0.0f,0.0f) |
float3_one | float3(1.0f,1.0f,1.0f) |
float3_neg_one | float3(-1.0f,-1.0f,-1.0f) |
float3_up | float3(0.0f,0.0f,1.0f) |
float3_isrgb | float3(float_isrgb,float_isrgb,float_isrgb) |
float3_luma | float3(0.299f,0.587f,0.114f) |
float2_zero | float3(2.2f,2.2f,2.2f) |
float2_one | float2(1.0f,1.0f) |
float2_neg_one | float2(-1.0f,-1.0f) |
float2_isrgb | float2(float_isrgb,float_isrgb) |
int4_zero | int4(0,0,0,0) |
int4_one | int4(1,1,1,1) |
int4_neg_one | int4(-1,-1,-1,-1) |
int3_zero | int3(0,0,0) |
int3_one | int3(1,1,1) |
int3_neg_one | int3(-1,-1,-1) |
int2_zero | int2(0,0) |
int2_one | int2(1,1) |
int2_neg_one | int2(-1,-1) |
PI | 3.141592654f |
PI2 | 6.283185308f |
PI05 | 1.570796327f |
LOG2 | 0.693147181f |
LOG10 | 2.302585093f |
SQRT2 | 1.414213562f |
EPSILON | 1e-6f |
INFINITY | 1e+9f |
DEG2RAD | PI / 180.0f |
RAD2DEG | 180.0f / PI |
STATICARRAY (float2,halton16,16) | Array containing Halton sequence. |
STATICARRAY (float2,halton8,8) | Array containing Halton sequence. |
Main Function
Void Main Function
To start and end the void Main function of the fragment shader (when you don't need to provide the output color value but depth), use the following instructions:
MAIN_VOID_BEGIN(STRUCT_IN)
<your code here>
MAIN_VOID_END
This code is equivalent to:
void main() {
<your code here>
}
void main(STRUCT_IN IN) {
<your code here>
}
Main Function with Return Value
To start and end the Main function with return value, use the following instructions:
MAIN_BEGIN(STRUCT_OUT,STRUCT_IN)
<your code here>
MAIN_END
This code is equivalent to:
void main() {
<your code here>
}
STRUCT_OUT main(STRUCT_IN IN) {
STRUCT_OUT OUT;
<your code here>
return OUT; }
Geometry Shader Main Function
To start and end the Main function of the geometry shader, use the following instructions:
MAIN_GEOM_BEGIN(STRUCT_OUT,STRUCT_IN)
<your code here>
END_GEOM
This code is equivalent to:
layout(TYPE_GEOM_IN) in;
layout(TYPE_GEOM_OUT,max_vertices = MAX_VERTICES_GEOM) out;
void main() {
<your code here>
}
[maxvertexcount(MAX_VERTICES_GEOM)]
void main(TYPE_GEOM_IN STRUCT_IN IN[COUNT_GEOM_IN],inout TYPE_GEOM_OUT<STRUCT_OUT> stream) {
STRUCT_OUT OUT;
<your code here>
}
Global Variables
To define a global variable, use the following syntax:
GLOBAL <your var>
This is equal to the following GLSL and HLSL commands:
uniform <your var>
uniform <your var>
Static Variables and Arrays
Static Variables
To define a static variable, use the following syntax:
STATICVAR <your var>
This is equal to the following GLSL and HLSL commands:
const <your var>
static const <your var>
Static Arrays
To work with static arrays by using UUSL, use the following instructions:
STATICARRAY(TYPE,NAME,SIZE)
<your array members>
ENDARRAY
- TYPE - the type of the array (float, etc.).
- NAME - the name of the array.
- SIZE - the size of the array.
This code block is equivalent to:
TYPE NAME [SIZE] = TYPE[](<your array members>);
static const TYPE NAME [SIZE] = {<your array members>};
Blending Presets
UUSL contains blending presets. When you specify the type of blending in material, the USSL wrapper automatically defines a new definition, that you can use in your shader:
Blending type | UUSL |
---|---|
BLEND_SRC_FUNC_SRC_ALPHA && BLEND_DEST_FUNC_ONE_MINUS_SRC_ALPHA | BLEND_ALPHABLEND |
BLEND_SRC_FUNC_ONE && BLEND_DEST_FUNC_ONE | BLEND_ADDITIVE |
BLEND_SRC_FUNC_DEST_COLOR && BLEND_DEST_FUNC_ZERO | BLEND_MULTIPLICATIVE |
BLEND_SRC_FUNC_NONE && BLEND_DEST_FUNC_NONE | BLEND_NONE |
HLSL features
HLSL Flow Control Attributes
UUSL | OpenGL | Direct3D | Description |
---|---|---|---|
branch | - | [branch] | Performs branching using control flow instructions. |
call | - | [call] | Prevents inlining of a function. |
flatten | - | [flatten] | Performs branching using conditional move instructions. |
ifAll | - | [ifAll] | Executes the conditional part of an if statement when the condition is true for all threads on which the current shader is running. |
ifAny | - | [ifAny] | Executes the conditional part of an if statement when the condition is true for any thread on which the current shader is running. |
isolate | - | [isolate] | Optimizes the specified HLSL code independently of the surrounding code. |
loop | - | [loop] | Gives preference to flow control constructs. |
maxexports | - | [maxexports] | Specifies the maximum number of export instructions that will execute along any path from the entry point to an exit. |
maxInstructionCount | - | [maxInstructionCount] | Sets the maximum number of instructions available to a shader. |
maxtempreg | - | [maxtempreg] | Restricts temporary register usage to the number of registers specified. Generates a compiler error if unsuccessful. |
noExpressionOptimizations | - | [noExpressionOptimizations] | Avoids optimization of expressions. |
predicate | - | [predicate] | Performs branching by using predication. |
predicateBlock | - | [predicateBlock] | Performs branching by using predicated exec blocks. |
reduceTempRegUsage | - | [reduceTempRegUsage] | Restricts temporary register usage to the number of registers specified. Generates a compiler warning if unsuccessful. |
removeUnusedInputs | - | [removeUnusedInputs] | Removes unused interpolator inputs from pixel shaders. |
sampreg | - | [sampreg] | Sets the ranges of pixel sampler and vertex sampler registers used by the compiler. |
unroll | - | [unroll] | Avoids flow control constructs. |
unused | - | [unused] | Suppresses warnings about unused shader parameters. |
xps | - | [xps] | Specifies that all vertex fetch operations are done after the last vfetch instruction. This instruction is used to reduce the latency back to the command processor to free the vertex buffer. |
earlydepthstencil | - | [earlydepthstencil] | Forces depth-stencil testing before a shader executes. Doesn't work with custom depth. |
Interpolation Modifiers
UUSL | OpenGL | Direct3D | Description |
---|---|---|---|
MODIFER_LINEAR | - | linear | Interpolate between shader inputs; linear is the default value if no interpolation modifier is specified. |
MODIFER_CENTROID | - | centroid | Interpolate between samples that are somewhere within the covered area of the pixel (this may require extrapolating end points from a pixel center). Centroid sampling may improve antialiasing if a pixel is partially covered (even if the pixel center is not covered). The centroid modifier must be combined with either the linear or noperspective modifier. |
MODIFER_NOINTERPOLATION | - | nointerpolation | Do not interpolate. |
MODIFER_NOPERSPECTIVE | - | noperspective | Do not perform perspective-correction during interpolation. The noperspective modifier can be combined with the centroid modifier. |
MODIFER_SAMPLE | - | sample | Interpolate at sample location rather than at the pixel center. This causes the pixel shader to execute per-sample rather than per-pixel. |
See Also
See also the article on Interpolation Modifiers.
Constants and Structs
Structs
In USSL structs is the way to organize the bunch of input and output data.
To start using structs in your shader code, use the following instructions:
STRUCT(NAME)
<your data>
END
- NAME - the name of the struct.
Here is an example of vertex shader input struct:
// 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
After that, you should pass the VERTEX_IN struct to the main function of the vertex shader.
Constants
For using constant buffer in your shader code, use the following instructions:
CBUFFER(NAME)
<your data>
END
- NAME - the name of the cbuffer.
Here is an example of using constant buffer:
CBUFFER(parameters)
UNIFORM float grayscale_power;
END
If you defined this parameter in the material, you'll be able to specify this value.
See Also
- How we use CBUFFER instruction in the tutorial on shaders for post-process pass.
For Loop
There is a for loop implemented in UUSL:
forloop(NAME,BEGIN,END)
for(int NAME = (BEGIN); NAME < (END); NAME++)
This command exports the shader program into a file: for Direct3D the file will have an .hlsl extension, for OpenGL the file will have an .glsl extension.
The command expands all of the predefined UUSL syntax and creates shader files in native languages for both graphic APIs.
Shader Export
To export shader, use the following command:
EXPORT_SHADER(FILE)
- FILE - The name of the file.
This command exports the shader program into a file: for Direct3D the file will have an .hlsl extension, for OpenGL the file will have an .glsl extension.
The command expands all of the predefined UUSL syntax and creates shader files in native languages for both graphic APIs.