# GLSL Syntax

## Additional shader example for understanding syntax

```

#ifdef GL_ES
precision highp float;
#endif

IN vec2 texCoord;

// Uniform variables: 
// bridge between  CPU - GPU that allows mapping external information 
// For example: time
uniform float uTime;


{{MODULES_HEAD}}

void main()
{
  
    /* Declaration of variables
       type name = value; */

    // Real numbers
    float number_0 = 1.0; // with dot
    int number_1 = 1;

    // Vectors 
    // 2 dimensions [_ ,_ ]
    vec2 v2_0 = vec2(0.,1.);
    vec2 v2_1 = vec2(number_0,number_1);

    //3 dimensions [_ ,_ ,_ ]
    vec3 v3_0 = vec3(0.,0.5,1.);
    vec3 v3_1 = vec3(v2_0,1.);
    vec3 v3_2 = vec3(v2_0,number_0);

    //4 dimensions [_ ,_ ,_ ,_ ]
    vec4 v4_0 = vec4(0.,0.25,0.5,1.);
    vec4 v4_1 = vec4(v2_0,v2_1);
    vec4 v4_2 = vec4(v3_0,0.);

    // Referencing vectors information
    // [r, g, b, a] || [x , y , z , w] 

    float numero_2 = v4_0.r; // is equivalent to v4_0.x
    vec2 v2_2 = v4_0.rg;     // is equivalent to v4_0.xy
    vec3 v3_3 = v4_0.gbr;    // is equivalent to v4_0.yzx

    gl_FragColor = vec4(0.5); // [ (r, g ,b , a) ]  with values in between 0. y 1.
}

```

## Functions to explore

Complete list of functions: 

* [https://www.shaderific.com/glsl-functions ](https://www.shaderific.com/glsl-functions)
* <https://thebookofshaders.com/glossary/>

### FUNCTIONS

#### Trigonometry&#x20;

cos(x)&#x20;

sin(x)

tan(x)

Power pow(x, 0.5) == sqrt(x)&#x20;

pow(x, 1.)&#x20;

pow(x, 2.)&#x20;

pow(x, n) for any n:=number&#x20;

sqrt(x): square root

&#x20;inversesqrt(x) 1./sqrt(x)

#### Exponentials&#x20;

exp(x) : base 10&#x20;

exp2(x): base 2

#### Logarithms&#x20;

log(x) : base 10&#x20;

log2(x) : base 2

#### Geometry&#x20;

length(x): length of a vector in the Euclidean norm.&#x20;

distance(x,y): distance between x and y&#x20;

dot(x,y): inner product between x and y (scalar product)

#### Other&#x20;

abs(x) : absolute value of x. E.g. abs(1)=1, abs(-1)=1&#x20;

sign(x) : sign of x. E.g. sign(1)=1 sign(-1)=0&#x20;

floor(x) : the nearest whole number that is less than x. Ex: floor(3.14) = 3&#x20;

ceiling(x):the nearest integer that is greater than x. Example: ceiling(3.14) = 4&#x20;

fract(x): the fractional part of x. Example: fract(3.14)= .14;&#x20;

min(a,b): minimum value between a and b&#x20;

max(a,b): minimum value between a and b&#x20;

clamp(x, a, b): if `x` is less than `a` returns a, if `x` is greater than `b` returns `b`, otherwise returns `x`.

mod(x, y): returns the remainder of the division of `x divided by` y\`

mix(x, y, a): x\*(1.-a)+y*a*&#x20;

*step(x, a): returns 0 if x <= a, and returns 1 if x > a.*&#x20;

*smoothstep(x,a,b): returns 0 if x\<a, interpolates between 0 and 1 if a\<x<=b, returns 1 if x > b.*&#x20;

*Example for use in function explorer:*&#x20;

*`float y = cos(cos(cos(x`*`x+u_time*.1),1.5)*10.-u_time);`