GLSL Built-in Functions Reference

Complete reference for GLSL ES 1.0 / WebGL functions.

Trigonometric Functions

Function	Description	Range
`sin(x)`	Sine	[-1, 1]
`cos(x)`	Cosine	[-1, 1]
`tan(x)`	Tangent	unbounded
`asin(x)`	Arc sine	[-PI/2, PI/2]
`acos(x)`	Arc cosine	[0, PI]
`atan(y, x)`	Arc tangent (quadrant-aware)	[-PI, PI]
`atan(y_over_x)`	Arc tangent	[-PI/2, PI/2]

All accept float, vec2, vec3, vec4. Input in radians.

Exponential Functions

Function	Description
`pow(x, y)`	x raised to power y
`exp(x)` / `exp2(x)`	e^x / 2^x
`log(x)` / `log2(x)`	Natural / Base-2 logarithm
`sqrt(x)` / `inversesqrt(x)`	Square root / 1/sqrt(x)

Common Functions

Function	Description
`abs(x)` / `sign(x)`	Absolute value / -1, 0, or 1
`floor(x)` / `ceil(x)`	Round down / up
`fract(x)`	x - floor(x)
`mod(x, y)`	x - y * floor(x/y)
`min(x, y)` / `max(x, y)`	Minimum / Maximum
`clamp(x, min, max)`	Constrain to range
`mix(a, b, t)`	Linear interpolation: a(1-t) + bt
`step(edge, x)`	0.0 if x < edge, else 1.0
`smoothstep(e0, e1, x)`	Hermite interpolation

Geometric Functions

Function	Description
`length(v)` / `distance(a, b)`	Magnitude / Distance
`dot(a, b)` / `cross(a, b)`	Dot / Cross product
`normalize(v)`	Unit vector
`reflect(i, n)` / `refract(i, n, eta)`	Reflection / Refraction

Vector Relational Functions

lessThan, lessThanEqual, greaterThan, greaterThanEqual, equal, notEqual - Return bvec. any(bvec), all(bvec), not(bvec) - Boolean operations.

Texture Functions

Function	Description
`texture2D(sampler, coord)`	Sample 2D texture
`textureCube(sampler, coord)`	Sample cube map

Constants

#define PI 3.14159265359
#define TWO_PI 6.28318530718
#define HALF_PI 1.57079632679

Type Constructors

vec2(x), vec2(x, y)
vec3(x), vec3(xy, z), vec3(x, y, z)
vec4(x), vec4(xyz, w), vec4(xy, zw)
mat2(a, b, c, d), mat3(...), mat4(...)

Operators

+  -  *  /           // Arithmetic (component-wise)
<  >  <=  >=  ==  != // Comparison
&&  ||  !            // Logical
mat * mat            // Matrix multiply
mat * vec            // Transform vector

Qualifiers

attribute  // Vertex input
uniform    // Constant across draw
varying    // Interpolated vertex->fragment
lowp / mediump / highp  // Precision
in / out / inout / const // Parameters

Built-in Variables

// Fragment Shader
vec4 gl_FragCoord;   // Window coordinates
vec4 gl_FragColor;   // Output color (write only)
bool gl_FrontFacing; // Front face?
vec2 gl_PointCoord;  // Point sprite [0,1]

// Vertex Shader
vec4 gl_Position;    // Clip-space position
float gl_PointSize;  // Point size

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