glsl函数之通用函数_glsl abs

glsl函数之通用函数

abs

Return the absolute value of the parameter.

float abs(float x)
vec2 abs(vec2 x)
vec3 abs(vec3 x)
vec4 abs(vec4 x)

sign

Extract the sign of the parameter

float sign(float x)
vec2 sign(vec2 x)
vec3 sign(vec3 x)
vec4 sign(vec4 x)

floor

Find the nearest integer less than or equal to the parameter

float floor(float x)
vec2 floor(vec2 x)
vec3 floor(vec3 x)
vec4 floor(vec4 x)

ceil

Find the nearest integer that is greater than or equal to the parameter

float ceil(float x)
vec2 ceil(vec2 x)
vec3 ceil(vec3 x)
vec4 ceil(vec4 x)

fract

Compute the fractional part of the argument

float fract(float x)
vec2 fract(vec2 x)
vec3 fract(vec3 x)
vec4 fract(vec4 x)

mod

Compute value of one parameter modulo another

float mod(float x, float y)
vec2 mod(vec2 x, vec2 y)
vec3 mod(vec3 x, vec3 y)
vec4 mod(vec4 x, vec4 y)

vec2 mod(vec2 x, float y)
vec3 mod(vec3 x, float y)
vec4 mod(vec4 x, float y)

Description

mod() returns the value of x modulo y. This is computed as x - y * floor(x/y).

min

Return the lesser of two values

float min(float x, float y)
vec2 min(vec2 x, vec2 y)
vec3 min(vec3 x, vec3 y)
vec4 min(vec4 x, vec4 y)

vec2 min(vec2 x, float y)
vec3 min(vec3 x, float y)
vec4 min(vec4 x, float y)

y = min(x,0.5);

max

Return the greater of two values

float max(float x, float y)
vec2 max(vec2 x, vec2 y)
vec3 max(vec3 x, vec3 y)
vec4 max(vec4 x, vec4 y)

vec2 max(vec2 x, float y)
vec3 max(vec3 x, float y)
vec4 max(vec4 x, float y)

y = max(x,0.5);

clamp

Constrain a value to lie between two further values

float clamp(float x, float minVal, float maxVal)
vec2 clamp(vec2 x, vec2 minVal, vec2 maxVal)
vec3 clamp(vec3 x, vec3 minVal, vec3 maxVal)
vec4 clamp(vec4 x, vec4 minVal, vec4 maxVal)

vec2 clamp(vec2 x, float minVal, float maxVal)
vec3 clamp(vec3 x, float minVal, float maxVal)
vec4 clamp(vec4 x, float minVal, float maxVal)

y = clamp(x,0.,1.);

mix

Constrain a value to lie between two further values

float mix(float x, float y, float a)
vec2 mix(vec2 x, vec2 y, vec2 a)
vec3 mix(vec3 x, vec3 y, vec3 a)
vec4 mix(vec4 x, vec4 y, vec4 a)

vec2 mix(vec2 x, vec2 y, float a)
vec3 mix(vec3 x, vec3 y, float a)
vec4 mix(vec4 x, vec4 y, float a)

Description

mix() performs a linear interpolation between x and y using a to weight between them. The return value is computed as x×(1−a)+y×a.

step

Generate a step function by comparing two values

float step(float edge, float x)
vec2 step(vec2 edge, vec2 x)
vec3 step(vec3 edge, vec3 x)
vec4 step(vec4 edge, vec4 x)

vec2 step(float edge, vec2 x)
vec3 step(float edge, vec3 x)
vec4 step(float edge, vec4 x)

y = step(0.5,x);

smoothstep

Perform Hermite interpolation between two values

float smoothstep(float edge0, float edge1, float x)
vec2 smoothstep(vec2 edge0, vec2 edge1, vec2 x)
vec3 smoothstep(vec3 edge0, vec3 edge1, vec3 x)
vec4 smoothstep(vec4 edge0, vec4 edge1, vec4 x)

vec2 smoothstep(float edge0, float edge1, vec2 x)
vec3 smoothstep(float edge0, float edge1, vec3 x)
vec4 smoothstep(float edge0, float edge1, vec4 x)

y = smoothstep(0.0,1.0,x);