// Copyright (c) 2023 Lachlan McDonald
// This work is licensed under the MIT License (MIT)
// https://github.com/lachlanmcdonald/magicavoxel-shaders
//
// This script utilises or modifies code from other projects or publications.
// Please see the attributions below for more information:
//
// 1. Copyright (c) 2011 Stefan Gustavson <https://github.com/ashima/webgl-noise>
//    MIT License (MIT)
//    https://github.com/ashima/webgl-noise/blob/master/LICENSE
//
// 2. Copyright (c) 2020 ValgoBoi <https://github.com/ValgoBoi/clover-noise>
//    MIT License (MIT)
//    https://github.com/ValgoBoi/clover-noise/blob/master/LICENSE
//
// xs brush/truchet [Mode] [Size] [Line Color] [Line Width] [Jitter] [Seed]
//
// xs_begin
// author : '@lmcdx.bsky.social'
// arg : { name = 'Mode'  var = 'm_mode'  range = '0 1'  value = '0'  step = '1'  precision = '0' }
// arg : { name = 'Size'  var = 'm_size'  range = '3 40'  value = '8'  step = '1'  precision = '0' }
// arg : { name = 'Line Color'  var = 'm_line_color'  range = '0 255'  value = '10'  step = '1'  precision = '0' }
// arg : { name = 'Line Width'  var = 'm_line_width'  range = '0 256'  value = '1'  step = '1'  precision = '0' }
// arg : { name = 'Jitter'  var = 'm_jitter'  range = '0 100'  value = '0'  step = '1'  precision = '0' }
// arg : { name = 'Seed'  var = 'global_seed'  range = '1 100'  value = '1'  step = '1'  precision = '0' }
// xs_end

int mode = int(m_mode);
vec2 dim = vec2(m_size + m_line_width);
float jitter = m_jitter / 100.0;

float hash(vec2 p, float seed) {
	p += global_seed + seed;
	return fract(1e4 * sin(17.0 * p.x + p.y * 0.1) * (0.1 + abs(sin(p.y * 13.0 + p.x))));
}

float hash(vec2 co) {
	return hash(co, 0.0);
}

vec2 hash22(vec2 p, float seed) {
	float a = hash(p, seed);
	return vec2(a, hash(p + a, seed));
}

vec2 hash22(vec2 p) {
	return hash22(p, 0.0);
}

float roundf(float f) {
	return f >= 0.5 ? ceil(f) : floor(f);
}

float pal(float f) {
	float k = float(i_num_color_sels) * clamp(0.0, 1.0, f);
	return color_sel(k);
}

float map(vec3 v) {
	vec2 cell = floor(v.xy / dim);
	vec2 local = mod(v.xy, dim);

	if (any(lessThan(local, vec2(m_line_width)))) {
		return m_line_color;
	} else {
		float a, b;
		vec2 j = hash22(cell);
		int rotate = int(hash(cell, 256.0) * 4.0);
		float dist;
		int comp;

		if (rotate == 0) {
			comp = 0;
			dist = (local.x + local.y) / (dim.x + dim.y);
		} else if (rotate == 1) {
			comp = 0;
			dist = ((dim.x - local.x) + local.y) / (dim.x + dim.y);
		} else if (rotate == 2) {
			comp = 0;
			dist = (local.x + (dim.y - local.y)) / (dim.x + dim.y);
		} else {
			comp = 1;
			dist = ((dim.x - local.x) + (dim.y - local.y)) / (dim.x + dim.y);
		}

		if (jitter > 0.0) {
			dist += mix(-1.0, 1.0, hash(v.xy)) * jitter;
		}

		if (mode == 0) {
			if (i_num_color_sels <= 2) {
				a = 0.0;
				b = 1.0;
			} else {
				float ka, kb;

				do {
					j = hash22(j);
					a = j.x;
					b = j.y;
					ka = floor(float(i_num_color_sels) * clamp(0.0, 1.0, a));
					kb = floor(float(i_num_color_sels) * clamp(0.0, 1.0, b));
				} while (ka == kb);
			}
		} else if (mode == 1) {
			a = mix(0.0, 0.5, j.x);
			b = mix(0.5, 1.0, j.x);
		}

		a = pal(a);
		b = pal(b);

		if (comp == 0) {
			return dist > 0.5 ? a : b;
		} else if (comp == 1) {
			return dist >= 0.5 ? a : b;
		}
	}
}