Skip to content

Latest commit

 

History

History
118 lines (83 loc) · 3.45 KB

Specs.md

File metadata and controls

118 lines (83 loc) · 3.45 KB
Raw

Shambda

Functional shading language aimed to be compiled to a SPIR-V module.

Syntax

Declarations

All declarations must finish with a double semicolon: ;;

Constant declaration:

constant <name>:<type> = <constant expression>;;
constant <name> = <constant expression>;;

Creates a new constant with the given value. The type is optional and can be inferred from the expression.

Uniform declaration:

uniform <name>:<type>;;

Declares an uniform. As uniforms cannot be initialized, it is mandatory to reference its type.

Fonction declaration:

<function name>:<return type> param1:<type of param1> param2:<type of param2> = <statements>;;
<function name> param1 param2 = <statements>;;

Declares a new function with the given name and return type (optional when inference is possible). Each parameter type is optional, except for the case of Stage functions.

A statement can be:

  • A local variable declaration let <name> := <expression>;;
  • Reassigning a value to a local variable <name> := <expression>;;
  • An expression (see Expressions)

Statements must be separated by single semicolons ;.

Literals:

Integers (32 bits): 42, -946, 45_555

Floating point numbers (32 bits): 4f, 58.57f, 3.14159f

Long integers (64 bits): 42L, -946L, 45_555L

Doubles (64 bits floating point numbers): 4d, 58.57d, 3.14159d

Unsigned integers: u59865

Unsigned long integers: u4564L

Booleans: true, false

Member accessing: Expression followed by dot and member name: vec4(1f (-8f) 5f 0f).x yields '1f'

Function calls:

f(arg1 arg2)

f() should be used for functions taking no arguments

Using a function as an argument: Just specify the name:

myfunc number = add (number 1f);;
[...]
functionTakingOtherFunction (myfunc);; (types ommited)

Identifiers:

Shambda follows the same rules as Java for its identifiers: starting with a letter, an underscore or a dollar sign, followed by letters, underscores, dollar signs or digits. __my$uperDuperAwe$0m3Identifier_

Accents are discouraged since they can lead to issues with encodings.

Base types:

int32, int64: integer and long integer types

float32, float64: floating point and double precision types

bool: boolean type

uint32, uint64: unsigned integer and unsigned long integer types

vec<size>(<component type>) (eg. vec4(bool): 4-dimensional boolean vector): vector of given size with constituents of type 'component type'

mat<size>(<vector type>) (eg. mat4(vec4(float32)): 4x4 float matrix): matrix with 'size' columns and each column is of type 'vector type'

<type>*: pointer type pointing to 'type'

File Structure

In a Shambda file, you can find declarations of constants, uniforms and functions.

Stage functions:

Each shader stage is represented by a function named with the name of said stage (eg. fragment = vec4(1f 1f 1f 1f);; is a fragment shader returning the color white for each pixel)

Supported stage are:

  • 'fragment': Returns a vec4(float32) representing the ouput color as a RGBA float vector. Parameters are equivalent to the input in a fragment shader.
  • 'vertex': Returns a vec4(float32) representing the position on screen of the vertex. Parameters are equivalent to the input in a vertex shader. The order of the parameters define their layout location.