From eb1592468ead076e0a9762add2eb36f098389654 Mon Sep 17 00:00:00 2001
From: raccoon <raccoon@home.net>
Date: Sun, 16 Mar 2025 19:59:52 +0500
Subject: [PATCH] Blender driver functions for animation bake

---
 blender_driver_func.py | 80 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 blender_driver_func.py

diff --git a/blender_driver_func.py b/blender_driver_func.py
new file mode 100644
index 0000000..d035cb2
--- /dev/null
+++ b/blender_driver_func.py
@@ -0,0 +1,80 @@
+from mathutils import *
+from math import *
+import bpy
+
+
+def angle_to_length(angle: float, target: float = 1.0) -> float:
+    """
+    Converts input angle to distance between two points in imaginary isosceles triangle with default angle of 180deg(!).
+    The distance is clamped to the target value.
+
+    :param angle: Input angle (in radians)
+    :type angle: float
+    :param target: Desired distance between end points, defaults to 1.0
+    :type target: float, optional
+    :return: The distance between two points
+    :rtype: float
+    """
+    if angle > 0:
+        return (target * 0.5 * sin(pi - angle)) / sin(angle * 0.5)  # School trigonometry
+    else:
+        return target
+
+
+def half_angle_to_length(angle: float, target: float = 1.0) -> float:
+    """
+    Converts input angle to distance between two points in imaginary isosceles triangle with default angle of 90deg.
+    The distance is clamped to the target value.
+
+    :param angle: Input angle (in radians)
+    :type angle: float
+    :param target: Desired distance between end points, defaults to 1.0
+    :type target: float, optional
+    :return: The distance between two points
+    :rtype: float
+    """
+    side = sqrt(pow(target, 2) * 0.5)  # Length of imaginary triangle's side
+    angle = abs(pi * 0.5 - angle)  # Default angle is 90deg
+    return (side * sin(angle)) / sin((pi - angle) * 0.5)
+
+
+def angle_compensation(angle: float) -> float:
+    side_len = sqrt(pow(pi * 0.5, 2) * 0.5)  # Length of imaginary triangle's side
+    distance = 0.5  # Distance to which move bone to
+
+    angle = abs(pi - angle)
+
+    # Compensate non-linear input angle
+    if angle > 0:
+        comp_angle = (side_len * 0.5 * sin(angle)) / sin(angle * 0.5)
+    else:
+        comp_angle = side_len
+
+    return (sqrt(pow(tan(comp_angle), 2) + 1) - 1) * distance
+
+
+def half_angle_compensation(angle: float) -> float:
+    side = sqrt(pow(pi * 0.25, 2) * 0.5)  # Length of imaginary triangle's side
+    angle = abs(angle)
+    final_angle = (side * sin(angle)) / sin((pi - angle) * 0.5)  # Width of imaginary triangle's base
+    return sqrt(pow(tan(final_angle), 2) + 1) - 1  # What the fuck??
+
+
+def test_compensation(angle: float) -> float:
+    side = sqrt(pow(pi * 0.5, 2) * 0.5)  # Triangle's side is now a desired output angle in radians
+    angle = abs(pi - angle)  # Rotate default angle to 180deg
+    return angle_to_length(angle, side)
+
+
+def test_half_compensation(angle: float) -> float:
+    side = pi * 0.25
+    angle = abs(pi * 0.5 + angle)  # Rotate default angle to 90deg
+    return half_angle_to_length(angle, side)
+
+
+bpy.app.driver_namespace["angle_to_length"] = angle_to_length
+bpy.app.driver_namespace["half_angle_to_length"] = half_angle_to_length
+bpy.app.driver_namespace["angle_compensation"] = angle_compensation
+bpy.app.driver_namespace["half_angle_compensation"] = half_angle_compensation
+bpy.app.driver_namespace["test_compensation"] = test_compensation
+bpy.app.driver_namespace["test_half_compensation"] = test_half_compensation