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9f85448 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 | from __future__ import annotations
import cv2
import numpy as np
_FRONT = (0, 1, 2, 3)
_BACK = (5, 4, 7, 6)
_SIDES = (
(4, 5, 1, 0),
(3, 2, 6, 7),
(4, 0, 3, 7),
(1, 5, 6, 2),
)
_LIGHT = np.array([0.35, -0.55, -1.0])
_LIGHT /= np.linalg.norm(_LIGHT)
_CARD_BG = (40, 37, 34)
_CARD_BORDER = (120, 115, 110)
_EDGE_COLOR = (150, 145, 140)
_SIDE_COLOR = np.array([120, 116, 112], dtype=np.float32)
def _rotation(yaw: float, pitch: float, roll: float) -> np.ndarray:
"""Build rotation matrix."""
cy, sy = np.cos(yaw), np.sin(yaw)
cp, sp = np.cos(pitch), np.sin(pitch)
cr, sr = np.cos(roll), np.sin(roll)
ry = np.array([[cy, 0, sy], [0, 1, 0], [-sy, 0, cy]])
rx = np.array([[1, 0, 0], [0, cp, -sp], [0, sp, cp]])
rz = np.array([[cr, -sr, 0], [sr, cr, 0], [0, 0, 1]])
return rz @ ry @ rx
class Object3D:
"""Textured 3D slab."""
def __init__(self, drawing_bgra: np.ndarray, thickness_ratio: float = 0.05) -> None:
self.texture = self._make_card(drawing_bgra)
h, w = self.texture.shape[:2]
self.aspect = w / max(h, 1)
self.thickness_ratio = thickness_ratio
self._corners = self._build_corners()
@staticmethod
def _make_card(drawing_bgra: np.ndarray) -> np.ndarray:
"""Flatten drawing to card."""
if drawing_bgra.shape[2] == 4:
rgb = drawing_bgra[:, :, :3].astype(np.float32)
alpha = (drawing_bgra[:, :, 3].astype(np.float32) / 255.0)[:, :, None]
else:
rgb = drawing_bgra.astype(np.float32)
alpha = np.ones(drawing_bgra.shape[:2] + (1,), dtype=np.float32)
h, w = rgb.shape[:2]
max_side = 900
if max(h, w) > max_side:
k = max_side / max(h, w)
rgb = cv2.resize(rgb, (int(w * k), int(h * k)), interpolation=cv2.INTER_AREA)
alpha = cv2.resize(alpha, (int(w * k), int(h * k)), interpolation=cv2.INTER_AREA)[:, :, None]
bg = np.full(rgb.shape, _CARD_BG, dtype=np.float32)
card = (bg * (1.0 - alpha) + rgb * alpha).astype(np.uint8)
cv2.rectangle(card, (0, 0), (card.shape[1] - 1, card.shape[0] - 1), _CARD_BORDER, 2)
return card
def _build_corners(self) -> np.ndarray:
"""Eight slab vertices."""
w = self.aspect * 0.5
h = 0.5
t = max(self.thickness_ratio, 0.005) * 0.5
return np.array(
[
(-w, -h, t), (w, -h, t), (w, h, t), (-w, h, t),
(-w, -h, -t), (w, -h, -t), (w, h, -t), (-w, h, -t),
],
dtype=np.float64,
)
@staticmethod
def _project(pts3d: np.ndarray, focal: float, distance: float, cx: float, cy: float):
"""Perspective project points."""
z = pts3d[:, 2] + distance
z = np.maximum(z, 1e-3)
x = focal * pts3d[:, 0] / z + cx
y = focal * pts3d[:, 1] / z + cy
return np.stack([x, y], axis=1), z
@staticmethod
def _shade(face_cam: np.ndarray) -> float:
"""Face lighting factor."""
n = np.cross(face_cam[1] - face_cam[0], face_cam[2] - face_cam[0])
norm = np.linalg.norm(n)
if norm < 1e-9:
return 0.2
n = n / norm
if n[2] > 0:
n = -n
return float(np.clip(abs(np.dot(n, _LIGHT)), 0.22, 1.0))
@staticmethod
def _quad_area(quad: np.ndarray) -> float:
"""Screen area of quad."""
x, y = quad[:, 0], quad[:, 1]
return 0.5 * abs(np.dot(x, np.roll(y, -1)) - np.dot(y, np.roll(x, -1)))
def _blit_texture(
self, out: np.ndarray, texture: np.ndarray, quad: np.ndarray, shade: float
) -> None:
"""Warp texture onto face."""
oh, ow = out.shape[:2]
x0 = int(np.floor(quad[:, 0].min()))
y0 = int(np.floor(quad[:, 1].min()))
x1 = int(np.ceil(quad[:, 0].max())) + 1
y1 = int(np.ceil(quad[:, 1].max())) + 1
x0, y0 = max(0, x0), max(0, y0)
x1, y1 = min(ow, x1), min(oh, y1)
if x1 - x0 < 2 or y1 - y0 < 2:
return
th, tw = texture.shape[:2]
src = np.array([[0, 0], [tw - 1, 0], [tw - 1, th - 1], [0, th - 1]], dtype=np.float32)
dst = (quad - np.array([x0, y0], dtype=np.float64)).astype(np.float32)
try:
m = cv2.getPerspectiveTransform(src, dst)
except cv2.error:
return
if not np.all(np.isfinite(m)):
return
size = (x1 - x0, y1 - y0)
warped = cv2.warpPerspective(texture, m, size, flags=cv2.INTER_LINEAR)
mask = cv2.warpPerspective(
np.full((th, tw), 255, np.uint8), m, size, flags=cv2.INTER_NEAREST
)
warped = np.clip(warped.astype(np.float32) * (0.70 + 0.30 * shade), 0, 255).astype(np.uint8)
roi = out[y0:y1, x0:x1]
a = (mask.astype(np.float32) / 255.0)[:, :, None]
out[y0:y1, x0:x1] = (roi * (1.0 - a) + warped * a).astype(np.uint8)
def render(
self,
background: np.ndarray,
yaw: float,
pitch: float,
roll: float = 0.0,
scale: float = 1.0,
distance: float = 3.0,
center: tuple[float, float] | None = None,
draw_edges: bool = True,
) -> np.ndarray:
"""Render object over background."""
out = background.copy()
oh, ow = out.shape[:2]
cx, cy = center if center is not None else (ow * 0.5, oh * 0.5)
focal = 1.7 * oh * max(scale, 0.05)
rot = _rotation(yaw, pitch, roll)
cam = self._corners @ rot.T
proj, depth = self._project(cam, focal, distance, cx, cy)
faces: list[tuple[float, tuple[int, ...], str]] = [
(float(depth[list(_FRONT)].mean()), _FRONT, "front"),
(float(depth[list(_BACK)].mean()), _BACK, "back"),
]
faces += [(float(depth[list(f)].mean()), f, "side") for f in _SIDES]
faces.sort(key=lambda item: item[0], reverse=True)
back_tex = None
for _, idx, kind in faces:
centre = cam[list(idx)].mean(axis=0)
view = centre + np.array([0.0, 0.0, distance])
if float(np.dot(centre, view)) >= 0.0:
continue
quad = proj[list(idx)]
if self._quad_area(quad) < 4.0:
continue
shade = self._shade(cam[list(idx)])
if kind == "front":
self._blit_texture(out, self.texture, quad, shade)
elif kind == "back":
if back_tex is None:
back_tex = cv2.flip(self.texture, 1)
back_tex = (back_tex.astype(np.float32) * 0.55).astype(np.uint8)
self._blit_texture(out, back_tex, quad, shade)
else:
color = np.clip(_SIDE_COLOR * shade, 0, 255)
cv2.fillConvexPoly(
out, quad.astype(np.int32), color.tolist(), lineType=cv2.LINE_AA
)
if draw_edges:
cv2.polylines(
out, [quad.astype(np.int32)], True, _EDGE_COLOR, 1, cv2.LINE_AA
)
return out
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