#version 300 es
precision highp float;
uniform mediump sampler2D u_tex;     // base pattern (REPEAT along u)
uniform mediump sampler2D u_noise;   // tileable noise (REPEAT along u)
#include "_graphics_uniforms.glsl"
in vec2 vTexCoord;
in vec4 vColor;
out vec4 fragColor;
void main() {
    vec4 tex = texture(u_tex, vTexCoord);
    // flowing energy: the noise scrolls tail-ward over the base pattern (u grows toward the head,
    // so +time shifts features toward the tail). speed is a multiple of 1/600 so the 600 s time
    // wrap lands on a whole number of noise tiles — no pop
    float n = texture(u_noise, vec2(vTexCoord.x + (u_timeParams.x * 0.35), vTexCoord.y)).r;
    float flow = mix(0.4, 1.6, n);
    fragColor = vec4(tex.rgb * tex.a * vColor.rgb * flow, vColor.a);
}