clamp()

Syntax

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

Live example

Edit the code and the preview updates as you type.

How it works

clamp(x, minVal, maxVal) keeps x inside a range:

• below minVal: returns minVal
• above maxVal: returns maxVal
• in between: returns x unchanged

In the example the gray diagonal line is the raw value. The green line follows it in the middle and goes flat at the top and bottom, where the value hits the limits. The limits breathe with u_time.

Typical uses

• Keeping colors valid: clamp(color, 0.0, 1.0) before writing to gl_FragColor.
• Safe input to other functions: sqrt(clamp(x, 0.0, 1.0)) or acos(clamp(d, -1.0, 1.0)) avoid undefined results from out-of-range input.
• Hard-edged progress bars: clamp((u_time - start) / duration, 0.0, 1.0) goes from 0 to 1 and then stays at 1.

Common mistakes

• Swapping the bounds. If minVal is greater than maxVal the result is undefined in GLSL and differs between GPUs.
• Expecting a smooth transition. clamp has sharp corners at both ends; use smoothstep when you want an eased curve.

Related functions

Tutorials that use clamp()

• Clamp Demo
  Use clamp() to keep values in range.
• Diagonal Gradient
  Combine vUv.x and vUv.y to create a diagonal gradient and interpolate colors with mix.
• Rectangle Border
  Create a border by subtracting an inner rectangle mask from an outer one.
• Clamp & Saturate
  Practice core GLSL math building blocks used across shaders.
• Smooth Min
  Blend two circle SDFs into one smooth shape with a smooth minimum function.
• SDF Shape Blend
  Combine circles, boxes, and smooth min to build a smoothly blended compound shape.