final_shader.frag

#include <flutter/runtime_effect.glsl>

uniform vec2 uSize;
uniform float iTime;
vec2 iResolution;
out vec4 fragColor;

#define PI 3.1415926535897932384626433832795

void main(void) {

    iResolution = uSize;
    vec2 fragCoord = FlutterFragCoord();
    
    vec2 center = fragCoord/iResolution.xy - vec2(0.5, 0.5);
    float dist = length(center);
    float p = (atan(center.y,center.x)) / (2.0 * PI);
    float numStripes = 12.0;
    bool stripeA = mod(floor((p * numStripes) + (sin(dist * 10.0 + sin(iTime)))), 2.0) == 1.0;
    bool stripeB = mod(floor((p * numStripes) - (sin(dist * 10.0 + cos(iTime)))), 2.0) == 1.0;
    vec3 col;
    if (stripeA && stripeB) {
        col = vec3(0.4);
    } else if (!stripeA && stripeB) {
        col = vec3(0.5, 0.2, 0.1);
    } else if (stripeA && !stripeB) {
        col = vec3(0.3, 0.2, 0.1);
    } else {
        col = vec3(0.7);
    }

    fragColor = vec4(col,1.0);
}