what is the maximum integer(unsigned integer) value that glsl can support?

Question

What's the maximum value of integer and unsigned integer that can be used in shader?

Answer 1

For OpenGL ES 3.x "lowp int" must be at least 9-bit twos complement, "mediump int" must be at least 16-bit twos complement, and "highp int" must be at least 32-bit twos complement.

Precision	Signed range	Unsigned range
lowp	-28 to 28-1	0 to 29-1
mediump	-215 to 215-1	0 to 216-1
highp	-231 to 231-1	0 to 232-1

Reference: Section 4.5.1 Range and Precision (page 53 in the PDF).

https://www.khronos.org/registry/OpenGL/specs/es/3.0/GLSL_ES_Specification_3.00.pdf