GLSL built-in function
lessThan()
Component-wise less-than comparison returning a boolean vector.
Demo version: GLSL ES 1.00 / WebGL 1Demo stage: Fragment
Syntax
bvec2 lessThan(vec2 x, vec2 y)
bvec3 lessThan(vec3 x, vec3 y)
bvec4 lessThan(vec4 x, vec4 y)
bvec2 lessThan(ivec2 x, ivec2 y)
bvec3 lessThan(ivec3 x, ivec3 y)
bvec4 lessThan(ivec4 x, ivec4 y)Parameters
- x
- Input value or left-hand vector
- y
- Right-hand vector or comparison value
Return value
A boolean vector containing true where each component of x is strictly less than its counterpart in y.
Live example
Edit the code and the preview updates as you type.
What lessThan does
Component-wise less-than comparison returning a boolean vector.
Read the preview
Selecting .x from lessThan(vec2(x,y),vec2(0.0)) marks the left half. Try a bound of vec2(-0.5) to restrict the selected region to the leftmost quarter.
Core call
float(lessThan(vec2(x,y),vec2(0.0)).x);
A bvec is not a scalar condition; reduce it with any or all.
Experiment
Change the final .x to .y while leaving the bound at zero. The comparison then paints the lower half because y, rather than x, must be negative.