Recommend changing variable name "smooth" to something else in the Landscape shader

[lynnhu]

When I select the landscape shader example from dropdown Processing 4 would freeze and throw an error :

RuntimeException: Cannot compile fragment shader:
ERROR: 0:113: 'smooth' : syntax error: syntax error

Turned out the function on line 111 in landscape.glsl is setting the variable name as "smooth" which seems to be recognized as a qualifier in GLSL:
vec3 smoothmix(vec3 a, vec3 b, float base, float smooth, float source)

Changed the name to something else like smoothValue and it runs now.