working render script ?

poetry.lock

@@ -125,6 +125,18 @@ files = [
     {file = "distlib-0.3.6.tar.gz", hash = "sha256:14bad2d9b04d3a36127ac97f30b12a19268f211063d8f8ee4f47108896e11b46"},
 ]
 
+[[package]]
+name = "fake-bpy-module-latest"
+version = "20230118"
+description = "Collection of the fake Blender Python API module for the code completion."
+category = "main"
+optional = false
+python-versions = ">=3.7"
+files = [
+    {file = "fake-bpy-module-latest-20230118.tar.gz", hash = "sha256:a3f45879347ef37b6fa5cd66ccc49634a14b420fa1b0fd196dfbf177d8602053"},
+    {file = "fake_bpy_module_latest-20230118-py3-none-any.whl", hash = "sha256:66d0b76ba65e01a91f74e77114705d744f3c2ad1078d060abf4a42c7fff9e79b"},
+]
+
 [[package]]
 name = "filelock"
 version = "3.9.0"
@@ -692,4 +704,4 @@ testing = ["coverage (>=6.2)", "coverage-enable-subprocess (>=1)", "flaky (>=3.7
 [metadata]
 lock-version = "2.0"
 python-versions = ">=3.8.1,<4.0"
-content-hash = "78e5e2403aaceb237ee187dd395971a4ee3a07af884a3d2be70e201a8285b2f4"
+content-hash = "70277d35aa55c1022524e37b75fcd711637ee16fb1737bc157244cf83d57efff"

pyproject.toml

@@ -10,6 +10,7 @@ numpy = "^1.23.5"
 python = ">=3.8.1,<4.0"
 rich = "^12.6.0"
 opencv-python = "^4.6.0.66"
+fake-bpy-module-latest = "^20230118"
 
 [tool.poetry.group.dev.dependencies]
 Flake8-pyproject = "^1.1.0"

src/blender/proj.py

@@ -1,10 +1,5 @@
-# https://blender.stackexchange.com/questions/38009/3x4-camera-matrix-from-blender-camera
-
 import bpy
 from mathutils import Matrix
-import pickle
-import numpy as np
-
 
 #---------------------------------------------------------------
 # 3x4 P matrix from Blender camera
@@ -27,7 +22,7 @@ def get_sensor_fit(sensor_fit, size_x, size_y):
 
 # Build intrinsic camera parameters from Blender camera data
 #
-# See notes on this in 
+# See notes on this in
 # blender.stackexchange.com/questions/15102/what-is-blenders-camera-projection-matrix-model
 # as well as
 # https://blender.stackexchange.com/a/120063/3581
@@ -66,7 +61,7 @@ def get_calibration_matrix_K_from_blender(camd):
     return K
 
 # Returns camera rotation and translation matrices from Blender.
-# 
+#
 # There are 3 coordinate systems involved:
 #    1. The World coordinates: "world"
 #       - right-handed
@@ -76,7 +71,7 @@ def get_calibration_matrix_K_from_blender(camd):
 #       - right-handed: negative z look-at direction
 #    3. The desired computer vision camera coordinates: "cv"
 #       - x is horizontal
-#       - y is down (to align to the actual pixel coordinates 
+#       - y is down (to align to the actual pixel coordinates
 #         used in digital images)
 #       - right-handed: positive z look-at direction
 def get_3x4_RT_matrix_from_blender(cam):
@@ -86,7 +81,7 @@ def get_3x4_RT_matrix_from_blender(cam):
         (0, -1, 0),
         (0, 0, -1)))
 
-    # Transpose since the rotation is object rotation, 
+    # Transpose since the rotation is object rotation,
     # and we want coordinate rotation
     # R_world2bcam = cam.rotation_euler.to_matrix().transposed()
     # T_world2bcam = -1*R_world2bcam @ location
@@ -97,7 +92,7 @@ def get_3x4_RT_matrix_from_blender(cam):
 
     # Convert camera location to translation vector used in coordinate changes
     # T_world2bcam = -1*R_world2bcam @ cam.location
-    # Use location from matrix_world to account for constraints:     
+    # Use location from matrix_world to account for constraints:
     T_world2bcam = -1*R_world2bcam @ location
 
     # Build the coordinate transform matrix from world to computer vision camera
@@ -117,28 +112,25 @@ def get_3x4_P_matrix_from_blender(cam):
     RT = get_3x4_RT_matrix_from_blender(cam)
     return K@RT, K, RT
 
-def run_script(scene):
-    with open(PICKLE_PATH, 'rb') as file:
-        matrices = pickle.load(file)
+# ----------------------------------------------------------
+if __name__ == "__main__":
+    # Insert your camera name here
+    cam = bpy.data.objects['Camera']
+    P, K, RT = get_3x4_P_matrix_from_blender(cam)
+    print("K")
+    print(K)
+    print("RT")
+    print(RT)
+    print("P")
+    print(P)
 
-    projection_matrix, _, _ = get_3x4_P_matrix_from_blender(scene.camera)
-    matrices.append(np.array(projection_matrix))
-    
-    with open(PICKLE_PATH, 'wb') as file:
-        pickle.dump(matrices, file)
+    print("==== 3D Cursor projection ====")
+    pc = P @ bpy.context.scene.cursor.location
+    pc /= pc[2]
+    print("Projected cursor location")
+    print(pc)
 
-def setup_script(scene):
-    matrices = []
-    with open(PICKLE_PATH, 'wb') as file:
-        pickle.dump(matrices, file)
-
-PICKLE_PATH = "/tmp/pickle.truc"
-
-# clear handlers
-bpy.app.handlers.render_init.clear()
-bpy.app.handlers.frame_change_pre.clear()
-bpy.app.handlers.frame_change_post.clear()
-
-# add handler
-bpy.app.handlers.render_init.append(setup_script)
-bpy.app.handlers.frame_change_post.append(run_script)
+    # Bonus code: save the 3x4 P matrix into a plain text file
+    # Don't forget to import numpy for this
+    #nP = numpy.matrix(P)
+    #numpy.savetxt("/tmp/P3x4.txt", nP)  # to select precision, use e.g. fmt='%.2f'

src/blender/render.py

@@ -0,0 +1,67 @@
+import bpy
+import math
+import itertools
+import pathlib
+import pickle
+import sys
+import numpy as np
+
+# dirty hack to import proj.py
+dir = pathlib.Path(bpy.data.filepath).parent
+dir = dir / "src" / "blender"
+sys.path.append(str(dir))
+
+from proj import get_3x4_P_matrix_from_blender
+
+# setup output path
+EXPORT_PATH = pathlib.Path("/tmp/")
+
+# setup camera poses
+phis = [-45, 0, 45]
+thetas = [0, 45, 90, 135, 180, 225, 270, 315]
+
+# convert to radians
+phis = [math.radians(phi) for phi in phis]
+thetas = [math.radians(theta) for theta in thetas]
+
+# create all possible combinations
+poses = list(itertools.product(phis, thetas))
+
+# create export folders
+pathlib.Path(EXPORT_PATH / "images").mkdir(parents=True, exist_ok=True)
+pathlib.Path(EXPORT_PATH / "masks").mkdir(parents=True, exist_ok=True)
+pathlib.Path(EXPORT_PATH / "cameras").mkdir(parents=True, exist_ok=True)
+
+# set "File Output" nodes' "Base Path" property
+bpy.data.scenes["Scene"].node_tree.nodes["Image Output"].base_path = str(EXPORT_PATH / "images")
+bpy.data.scenes["Scene"].node_tree.nodes["Mask Output"].base_path = str(EXPORT_PATH / "masks")
+
+# get camera
+cam = bpy.data.objects["Camera"]
+
+for i, (phi, theta) in enumerate(poses):
+    print(f"Rendering pose {i}...")
+
+    # set camera pose
+    bpy.context.scene.objects["Empty"].rotation_euler[0] = phi
+    bpy.context.scene.objects["Empty"].rotation_euler[2] = theta
+
+    # get camera matrices
+    P, K, RT = get_3x4_P_matrix_from_blender(cam)
+
+    # save camera matrices
+    with open(EXPORT_PATH / "cameras" / f"{i:04d}.pickle", "wb") as f:
+        pickle.dump({
+            "P": np.array(P),
+            "K": np.array(K),
+            "RT": np.array(RT),
+        }, f)
+        print(f"Saved camera matrices: {i:04d}.pickle")
+
+
+    # set frame number
+    bpy.context.scene.frame_current = i
+
+    # render the frame
+    bpy.ops.render.render(write_still=False)
+