Added simple angle script Makefile and a simple shell nix

shell.nix

@@ -0,0 +1,12 @@
+{ pkgs ? import <nixpkgs> {} }:
+
+# Simple python shell for all packages
+
+pkgs.mkShell {
+  buildInputs = with pkgs; [
+    (pkgs.python313.withPackages (ps: with ps; [
+      matplotlib
+      numpy
+    ]))
+  ];
+}

simple-angle.py

@@ -0,0 +1,93 @@
+import numpy as np
+
+unit_x = np.array([1, 0, 0])
+unit_y = np.array([0, 1, 0])
+unit_z = np.array([0, 0, 1])
+
+# Axis are numbered from 1 to 3 from x to z
+
+def get_axis(axis):
+    match axis:
+        case 1:
+            ax = unit_x
+        case 2:
+            ax = unit_y
+        case 3:
+            ax = unit_z
+        case _:
+            ax = unit_x
+    return ax
+
+def proj(vec, axis=1):
+    ax = get_axis(axis)
+
+    return np.dot(vec, ax) * ax
+
+def abs_custom(vec):
+    l = 0
+    for i in range(3):
+        l += vec[i] ** 2
+    return np.sqrt(l)
+
+
+def rotate(v, angle=90, axis=1):
+    angle = angle/180 * np.pi
+    k = get_axis(axis)
+
+    return (
+        v * np.cos(angle)
+        + np.cross(k, v) * np.sin(angle)
+        + k * np.dot(k, v) * (1 - np.cos(angle))
+    )
+        
+def agl(a, b):
+    return np.round(np.acos(np.dot(a, b)/(abs_custom(a) * abs_custom(b)))/(2 * np.pi) * 360)
+
+def normalize(vec):
+    l = abs_custom(vec)
+    return vec/l
+
+def get_angles(source, target):
+    source_planar = source - proj(source, 3)
+    target_planar = target - proj(target, 3)
+
+    source_phi = agl(source_planar, unit_x)
+    target_phi = agl(target_planar, unit_x)
+
+    source_theta = agl(rotate(source, 90 - source_phi, 3), unit_z)
+    target_theta = agl(rotate(target, 90 - target_phi, 3), unit_z)
+
+    phi = None
+    theta = None
+
+    theta_diff = None
+    phi_diff = agl(source_planar, target_planar)
+    if source_phi < target_phi:
+        rota = rotate(source_planar, phi_diff, 3)
+        theta_diff = agl(rota, target)
+        phi = source_phi + phi_diff/2
+    else:
+        rota = rotate(target_planar, phi_diff, 3)
+        theta_diff = agl(rota, source)
+        phi = target_phi + phi_diff/2
+
+    if source_theta < target_theta:
+        theta = target_theta + theta_diff/2
+    else:
+        theta = source_theta + theta_diff/2
+
+    return (phi, theta)
+
+GRID_SIZE = 10
+
+source_orig = np.array([30, 20, 50])
+target_orig = np.array([30, 20, 20])
+
+for x in range(2):
+    for y in range(2):
+        x_size = x * GRID_SIZE
+        y_size = y * GRID_SIZE
+
+        phi, theta = get_angles(source_orig - unit_x * x_size - unit_y * y_size, target_orig - unit_x * x_size - unit_y * y_size)
+
+        print(f"For grid ({x}, {y}), phi = {phi} and theta = {theta}.")