#version 150

in vec4 vertColor;
in float vertTexCoord;

uniform float shimmerStrength;

out vec4 fragColor;

void main() {
	float strength = shimmerStrength * 0.375;
	float darkened = step(0.5, fract(vertTexCoord));
	fragColor = mix(vertColor, vec4(0.0, 0.0, 0.0, 1.0), strength * darkened);
}