// Author @patriciogv - 2015 - patriciogonzalezvivo.com
// Modified to use Gingerbread Man chaotic map

#ifdef GL_ES
precision mediump float;
#endif

uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_time;

vec2 skew (vec2 st) {
    vec2 r = vec2(0.0);
    r.x = 1.1547*st.x;
    r.y = st.y+0.5*r.x;
    return r;
}

vec3 simplexGrid (vec2 st) {
    vec3 xyz = vec3(0.0);

    vec2 p = fract(skew(st));
    if (p.x > p.y) {
        xyz.xy = 1.0-vec2(p.x,p.y-p.x);
        xyz.z = p.y;
    } else {
        xyz.yz = 1.0-vec2(p.x-p.y,p.y);
        xyz.x = p.x;
    }

    return fract(xyz);
}

// Gingerbread Man map
vec2 gingerbreadMan(vec2 pos, float time) {
    // Classic Gingerbread Man parameters with time modulation
    float a = 0.9 + 0.1 * sin(time * 0.3);
    
    // Multiple iterations for chaotic behavior
    vec2 p = pos;
    for(int i = 0; i < 8; i++) {
        float x_new = 1.0 - a * p.y + abs(p.x);
        float y_new = p.x;
        p = vec2(x_new, y_new);
    }
    
    return p;
}

// Alternative Gingerbread Man with different parameters
vec2 gingerbreadMan2(vec2 pos, float time) {
    // More complex version with time-varying parameters
    float a = 0.8 + 0.2 * sin(time * 0.5);
    float b = 1.2 + 0.3 * cos(time * 0.7);
    
    vec2 p = pos;
    for(int i = 0; i < 6; i++) {
        float x_new = b * (1.0 + 2.0 * a) - a * p.y + abs(p.x);
        float y_new = p.x;
        p = vec2(x_new, y_new);
        
        // Add some noise for extra complexity
        p += 0.01 * sin(p * 10.0 + time);
    }
    
    return p;
}

void main() {
    vec2 st = gl_FragCoord.xy/u_resolution.xy;
    vec3 color = vec3(0.0);

    // Scale and center for Gingerbread Man
    vec2 ginger_st = (st - 0.5) * 4.0;
    
    // Apply Gingerbread Man map
    vec2 ginger_pos = gingerbreadMan(ginger_st, u_time);
    
    // Also get the alternative version
    vec2 ginger_pos2 = gingerbreadMan2(ginger_st, u_time * 1.3);
    
    // Scale the space to see the grid
    st *= 8.0;
    
    // Use Gingerbread Man output to modulate the simplex grid
    vec2 modulated_st = st + ginger_pos * 0.3;
    
    // Create the simplex grid with chaotic modulation
    color = simplexGrid(modulated_st);
    
    // Add color based on Gingerbread Man positions
    color.r += 0.3 * (0.5 + 0.5 * sin(length(ginger_pos) * 5.0 + u_time));
    color.g += 0.2 * (0.5 + 0.5 * cos(ginger_pos.x * 3.0 + u_time * 2.0));
    color.b += 0.4 * (0.5 + 0.5 * sin(ginger_pos2.y * 4.0 + u_time * 1.5));
    
    // Enhance contrast
    color = mix(color, color * color, 0.3);
    
    // Vignette effect
    float vignette = 1.0 - length(st * 0.1);
    color *= vignette * vignette;

    gl_FragColor = vec4(color, 1.0);
}