hilbert.shadron

#version 420

#include <multisample>
#include "library/lerp.shadron"
#include "library/complexNumbers.shadron"
// #include "library/random.shadron"

image input_image = file() : map(repeat);

// param vec2 tweak : range(-1, 100);
param float tweak2 : range(-1, 2);

param float grid_edge_length : range(10, 200);
// param float grid_scale : range(0, 1);
param float angle : range(0, TAU);
// param vec2 vibrationMinMax: range(0, 0.1); // min/max

glsl vec4 orange = vec4(1.0, 0.5, 0, 1.0);
glsl vec4 background_color = vec4(vec3(0), 1.0);

glsl float manhattan(vec2 a, vec2 z) {
    return max(abs(a.x - z.x), abs(a.y - z.y));
}

glsl vec4 hilbert_animation_func(vec2 pos, float time) {
    float theta = angle;
    vec2 shift = vec2(0);
    pos -= shift;
    pos /= shadron_PixelSize;

    ivec2 grid_coord = ivec2(pos / grid_edge_length);
    bool toggle = false;
    if (grid_coord.x % 2 == 0) toggle = !toggle;
    if (grid_coord.y % 2 == 0) toggle = !toggle;
    vec2 dir = lerp(vec2(1,0), vec2(0, 1), toggle);
    pos -= dir * grid_edge_length * tweak2;

    float minScale = 0.5;
    float amplitude = (1.0 - minScale) / 2;
    float grid_scale = minScale + amplitude + amplitude*cos(shadron_Time); //shadron_Time - 1 * sin(shadron_Time);

    // float grid_edge_length = tweak.x;
    vec2 d = mod(pos, vec2(grid_edge_length));
    vec2 corner = pos - d;
    vec2 center = corner + grid_edge_length * 0.5;
    vec2 scaled = lerp(center, pos, 1/grid_scale);

    if (manhattan(pos, center)/grid_scale > 0.5 * grid_edge_length) return background_color;
    pos = scaled;


    pos *= shadron_PixelSize;
    pos += shift;

    vec4 color = texture(input_image,  pos);
    return color;
}

glsl vec4 hilbert_func(vec2 pos) {
    return hilbert_animation_func(pos, 0);
}

animation hilbert_animation = glsl(multisampleAnimation<hilbert_animation_func, 4, 1>, sizeof input_image);
export png_sequence(hilbert_animation, "frames/frame_?.png", 30, TAU);
// image hilbert_image = glsl(hilbert_func, sizeof input_image);