fov calculating python script

diff --git a/misc/tools/fov-calc.py b/misc/tools/fov-calc.py
new file mode 100755 (executable)
index 0000000..84d3bd5
--- /dev/null
+++ b/misc/tools/fov-calc.py
@@ -0,0 +1,38 @@
+#!/usr/bin/python3
+
+import math
+import argparse
+
+
+def calculate_fov(fov, horizontal, vertical, viewzoom):
+    viewzoom_multiplier = 1 / viewzoom
+    frustumy = math.tan(fov * math.pi / 360) * 0.75 * viewzoom_multiplier
+    frustumx = frustumy * horizontal / vertical
+
+    fovx = math.atan2(frustumx, 1) / math.pi * 360
+    fovy = math.atan2(frustumy, 1) / math.pi * 360
+
+    print(fov, "degrees of hfov with 4:3 resolution (unstretched without black bars) actually gives:")
+    print("Horizontal FOV =", fovx)
+    print("Vertical   FOV =", fovy)
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description='Process in-game fov cvars to horizontal and vertical degrees.')
+    parser.add_argument('fov', type=float,
+                        help="in-game fov cvar, degrees of hfov with 4:3 resolution, required field")
+    parser.add_argument('horizontalAspectRatio', type=float, default=16, nargs='?',
+                        help="Horizontal num of the aspect ratio, for 16:9 that is 16, default: 16")
+    parser.add_argument('verticalAspectRatio', type=float, default=9, nargs='?',
+                        help="Vertical num of the aspect ratio, for 16:9 that is 9, default: 9")
+    parser.add_argument('viewzoom', type=float, default=1, nargs='?',
+                        help="Zoom amount, default: 1 / no zoom")
+    args = parser.parse_args()
+
+    if (args.fov < 1 or args.fov > 170):
+        print("WARNING: Xonotic's fov is currently restricted between 1 and 170, calculations might be broken with this number.")
+    if (args.viewzoom < 1 or args.viewzoom > 30):
+        print("WARNING: Xonotic's zoom is currently restricted between 1 and 30, calculations might be broken with this number.")
+
+    calculate_fov(args.fov, args.horizontalAspectRatio, args.verticalAspectRatio, args.viewzoom)
+