"""2026-10-03
Divisões redux 03
Inspirado em sketch de Alexandre Villares
ericof.com|https://abav.lugaralgum.com/sketch-a-day/#sketch_2026_02_16
png
Sketch,py5,CreativeCoding
"""
from collections import deque
from dataclasses import dataclass
from dataclasses import field
from shapely import Polygon
from sketches.utils.draw import canvas
from sketches.utils.draw.cores import lerp_color_rgba
from sketches.utils.draw.cores.paletas import gera_paleta
from sketches.utils.helpers import sketches as helpers
import numpy as np
import py5
sketch = helpers.info_for_sketch(__file__, __doc__)
cor_fundo = py5.color(0)
paleta: deque[int] = gera_paleta("azul", como_deque=True)
divisoes: int = 5
@dataclass
class InfoGrupo:
vertices: list = field(default_factory=list)
formas: list = field(default_factory=list)
areas: list = field(default_factory=list)
area_maxima: float = 0.0
forma: py5.Py5Shape | None = None
grupos: dict[int, InfoGrupo] = {}
intensidade: float = 0.001
fator: float = 1.4
distorcao_va = 1.8
def cria_grupos(idx: int, largura: int, altura: int):
"""Initialize a division group from a rectangle covering the internal canvas."""
vertices = [
np.array(ponto)
for ponto in ((0, 0), (largura, 0), (largura, altura), (0, altura))
]
formas = []
formas.append((0, 1, 2, 3))
areas = [area_forma((0, 1, 2, 3), vertices)]
grupos[idx] = InfoGrupo(
forma=None,
vertices=vertices,
formas=formas,
areas=areas,
area_maxima=max(areas),
)
return grupos
def _divide_quadrado(
idx: int, forma: tuple[int, ...], vertices: list, div: int = 2
) -> list[tuple[int, ...]]:
"""Divide a quadrilateral into triangles based on div.
div=2: split along the shorter diagonal → 2 triangles, no new points.
div=3: midpoint of the shorter diagonal added → 3 triangles; the two
half-triangles each have area S/4 and the intact half has S/2
(best achievable balance with a single added point).
div=4: centroid added → 4 triangles, each S/4 for parallelograms and
approximately equal for distorted quads.
"""
a, b, c, d = forma
ac = py5.dist(*vertices[a], *vertices[c])
bd = py5.dist(*vertices[b], *vertices[d])
gi = len(vertices)
vertices.append((vertices[a] + vertices[b] + vertices[c] + vertices[d]) / gi)
novas_formas = [(a, b, c), (a, c, d)] if ac < bd else [(a, b, d), (b, c, d)]
match div:
case 3:
s = novas_formas.pop(-1)
novas_formas.append((s[0], s[1], gi))
novas_formas.append((gi, s[1], s[2]))
case 4:
novas_formas = [(a, b, gi), (b, c, gi), (c, d, gi), (d, a, gi)]
case _:
novas_formas = novas_formas
print(f"{idx} - 4 -> {len(novas_formas)}")
return novas_formas
def _divide_triangulo(
idx: int, forma: tuple[int, ...], vertices: list, div: int = 2
) -> list[tuple[int, ...]]:
"""Divide a triangle into smaller triangles based on edge lengths."""
a, b, c = forma
ab = py5.dist(*vertices[a], *vertices[b])
ab_m = (vertices[a] + vertices[b]) / div
bc = py5.dist(*vertices[b], *vertices[c])
bc_m = (vertices[b] + vertices[c]) / div
ca = py5.dist(*vertices[c], *vertices[a])
ca_m = (vertices[c] + vertices[a]) / div
novas_formas = []
if ab == bc == ca:
bci = len(vertices)
vertices.append(bc_m)
novas_formas.append((a, b, bci))
novas_formas.append((bci, a, c))
elif ab == bc:
cai = len(vertices)
vertices.append(ca_m)
novas_formas.append((a, b, cai))
novas_formas.append((cai, a, c))
elif bc == ca:
abi = len(vertices)
vertices.append(ab_m)
novas_formas.append((a, c, abi))
novas_formas.append((abi, b, c))
else:
novas_formas.append((a, c, b))
novas_formas.append((b, a, c))
print(f"{idx} - 3 -> {len(novas_formas)}")
return novas_formas
DIVIDE_FORMA = {
3: _divide_triangulo,
4: _divide_quadrado,
}
def divide_formas(idx: int):
"""Create the next subdivision level for the given group index."""
info = grupos.get(idx)
if info and info.forma:
# Não é necessário dividir novamente se já temos um grupo
# para essa quantidade de divisões
return
idx_anterior = idx - 1 if idx > 1 else 1
anterior = grupos[idx_anterior]
formas = anterior.formas
vertices = list(anterior.vertices)
novas_formas = []
while formas:
forma = formas.pop()
total = len(forma)
div = 2 if total == 3 else py5.random_int(2, 4)
funcao_divisao = DIVIDE_FORMA.get(total)
if funcao_divisao:
novas_formas.extend(funcao_divisao(idx, forma, vertices, div))
areas = [area_forma(forma, vertices) for forma in novas_formas]
info = InfoGrupo(
forma=None,
vertices=vertices,
formas=novas_formas,
areas=areas,
area_maxima=max(areas),
)
grupos[idx] = info
monta_grupo(idx)
def distorce(idx: int, intensidade=intensidade, fator=fator):
"""Apply radial distortion to the group's vertices based on center distance."""
info = grupos[idx]
vertices = info.vertices
meio = helpers.DIMENSOES.internal[0] / 2, helpers.DIMENSOES.internal[1] / 2
coordenadas = np.array(vertices)
coordenadas -= np.array((meio[0], meio[1]))
distancias = np.linalg.norm(coordenadas, axis=1)
fatores_escala = 1 + (intensidade * (distancias**fator))
coordenadas = distorcao_va * coordenadas / fatores_escala[:, np.newaxis]
coordenadas += np.array(meio)
info.vertices = coordenadas
_monta_grupo(info)
def _monta_grupo(info: InfoGrupo):
"""Build and store a py5 group shape from an `InfoGrupo` definition."""
grupo = py5.create_shape(py5.GROUP)
formas = info.formas
areas = info.areas
vertices = info.vertices
pares = list(zip(formas, areas, strict=False))
for forma, _ in pares:
poligono = py5.create_shape()
cor = paleta[0]
cor_proxima = paleta[1]
pontos = np.array(vertices)[np.array(forma)]
total = len(pontos)
with poligono.begin_closed_shape():
poligono.vertices(pontos)
cores = []
for i in range(total):
cor = lerp_color_rgba(cor, cor_proxima, i, (0, total))
cores.append(cor)
poligono.set_fills(cores)
poligono.set_stroke_weight(4)
grupo.add_child(poligono)
paleta.rotate()
info.forma = grupo
def monta_grupo(idx: int):
"""Create a renderable group shape for a stored subdivision group."""
info = grupos[idx]
if info.forma:
# Já temos um shape para esse grupo, não precisamos recriar
print(f"Shape para {idx} divisões já existe. Pulando criação.")
return
_monta_grupo(info)
def area_forma(forma, vertices):
"""Return the polygon area for a shape index tuple over a vertex list."""
return Polygon(np.array(vertices)[np.array(forma)]).area
def inicializa():
"""Rebuild every subdivision level from 1 up to `divisoes`."""
for idx in range(1, divisoes + 1):
grupos = cria_grupos(idx, *helpers.DIMENSOES.internal)
divide_formas(idx=idx)
print(f"{idx} - {grupos[idx].forma.get_child_count()}")
def setup():
"""Configure the sketch and precompute subdivision groups up to `divisoes`."""
py5.size(*helpers.DIMENSOES.external, py5.P3D)
inicializa()
def draw():
"""Render the current subdivision group and update frame overlay metadata."""
py5.background(cor_fundo)
info = grupos[divisoes]
if grupo := info.forma:
with py5.push():
py5.shape_mode(py5.CENTER)
py5.translate(*helpers.DIMENSOES.centro)
py5.shape(grupo)
fps = py5.get_frame_rate()
py5.window_title(f"Divisões: {divisoes} - Frame Rate: {fps:.2f}")
# Credits and go
canvas.sketch_frame(
sketch,
cor_fundo,
"large_transparent_white",
"transparent_white",
version=2,
)
def key_pressed():
"""Handle keyboard controls for saving, subdividing, and distortion."""
global divisoes
key = py5.key
if key == " ":
salva_e_encerra()
elif key == "r":
inicializa()
elif key == "a":
divisoes -= 1 if divisoes > 1 else 0
divide_formas(divisoes)
elif key == "d":
divisoes += 1
divide_formas(divisoes)
elif key == "w":
distorce(divisoes)
def salva_e_encerra():
"""Stop rendering, save the current frame, and exit the sketch."""
py5.no_loop()
canvas.save_sketch_image(sketch)
py5.exit_sketch()
if __name__ == "__main__":
py5.run_sketch()
