1 files changed, 84 insertions, 0 deletions
diff --git a/intern/cycles/blender/addon/camera.py b/intern/cycles/blender/addon/camera.py
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+++ b/intern/cycles/blender/addon/camera.py
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+#
+# Copyright 2011-2021 Blender Foundation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# <pep8 compliant>
+
+# Fit to match default projective camera with focal_length 50 and sensor_width 36.
+default_fisheye_polynomial = [-1.1735143712967577e-05,
+                              -0.019988736953434998,
+                              -3.3525322965709175e-06,
+                              3.099275275886036e-06,
+                              -2.6064646454854524e-08]
+
+# Utilities to generate lens polynomials to match built-in camera types, only here
+# for reference at the moment, not used by the code.
+def create_grid(sensor_height, sensor_width):
+    import numpy as np
+    if sensor_height is None:
+        sensor_height = sensor_width / (16 / 9)  # Default aspect ration 16:9
+    uu, vv = np.meshgrid(np.linspace(0, 1, 100), np.linspace(0, 1, 100))
+    uu = (uu - 0.5) * sensor_width
+    vv = (vv - 0.5) * sensor_height
+    rr = np.sqrt(uu ** 2 + vv ** 2)
+    return rr
+
+
+def fisheye_lens_polynomial_from_projective(focal_length=50, sensor_width=36, sensor_height=None):
+    import numpy as np
+    rr = create_grid(sensor_height, sensor_width)
+    polynomial = np.polyfit(rr.flat, (-np.arctan(rr / focal_length)).flat, 4)
+    return list(reversed(polynomial))
+
+
+def fisheye_lens_polynomial_from_projective_fov(fov, sensor_width=36, sensor_height=None):
+    import numpy as np
+    f = sensor_width / 2 / np.tan(fov / 2)
+    return fisheye_lens_polynomial_from_projective(f, sensor_width, sensor_height)
+
+
+def fisheye_lens_polynomial_from_equisolid(lens=10.5, sensor_width=36, sensor_height=None):
+    import numpy as np
+    rr = create_grid(sensor_height, sensor_width)
+    x = rr.reshape(-1)
+    x = np.stack([x**i for i in [1, 2, 3, 4]])
+    y = (-2 * np.arcsin(rr / (2 * lens))).reshape(-1)
+    polynomial = np.linalg.lstsq(x.T, y.T, rcond=None)[0]
+    return [0] + list(polynomial)
+
+
+def fisheye_lens_polynomial_from_equidistant(fov=180, sensor_width=36, sensor_height=None):
+    import numpy as np
+    return [0, -np.radians(fov) / sensor_width, 0, 0, 0]
+
+
+def fisheye_lens_polynomial_from_distorted_projective_polynomial(k1, k2, k3, focal_length=50, sensor_width=36, sensor_height=None):
+    import numpy as np
+    rr = create_grid(sensor_height, sensor_width)
+    r2 = (rr / focal_length) ** 2
+    r4 = r2 * r2
+    r6 = r4 * r2
+    r_coeff = 1 + k1 * r2 + k2 * r4 + k3 * r6
+    polynomial = np.polyfit(rr.flat, (-np.arctan(rr / focal_length * r_coeff)).flat, 4)
+    return list(reversed(polynomial))
+
+def fisheye_lens_polynomial_from_distorted_projective_divisions(k1, k2, focal_length=50, sensor_width=36, sensor_height=None):
+    import numpy as np
+    rr = create_grid(sensor_height, sensor_width)
+    r2 = (rr / focal_length) ** 2
+    r4 = r2 * r2
+    r_coeff = 1 + k1 * r2 + k2 * r4
+    polynomial = np.polyfit(rr.flat, (-np.arctan(rr / focal_length / r_coeff)).flat, 4)
+    return list(reversed(polynomial))