GLSL mod()

The mod() function is a built-in function in the GLSL shading language that computes the remainder of the division \a / \b. It returns the value a - b * trunc(a / b).

The mod() function takes two arguments, both of which must be the same data type. The function returns a value with the same data type as the input arguments.

Syntax

The syntax for the mod() function is as follows:

T mod(T a, T b)

Where:

• T is any valid GLSL data type, such as float, vec2, vec3, vec4, int, ivec2, ivec3, ivec4, bool, bvec2, bvec3, bvec4, mat2, mat3, mat4, and so on.
• a is the dividend, the numerator of the division.
• b is the divisor, the denominator of the division.

The mod() function can also be called with a single argument, in which case it returns the same value as the input argument, but with a positive sign. This is equivalent to calling mod(a, a).

Example

float a = 16.0;
float b = 3.0;
float result = mod(a, b); // result = 1.0

In this example, the mod() function is used to compute the remainder of the division 16 / 3, which gives a remainder of 1.

Restrictions

The mod() function has some restrictions in GLSL:

• The divisor must be non-zero. If the divisor is zero, the behavior of the function is undefined.
• The dividend and divisor must be of the same data type.
• For floating-point types, the behavior of mod() is undefined if the divisor or dividend is NaN.

See Also

• Trigonometric functions
• Math functions
• GLSL language specification