shader_type canvas_item;
uniform float a: hint_range(0.0, 1.0, 0.1) = 0;
uniform float b: hint_range(0.0, 1.0, 0.1) = 0;
void fragment() {
if (UV.x < a) {
if (UV.x > b) {
COLOR.a = 1.0;
} else {
COLOR.a = 0.0;
}