Casting from float32 to Radian[float32] for assigning Node2D rotation property with Vector2 angle()

[guntur-ctech]

I'm learning Nim and trying to convert code from GDScript. Here's my current code:

import gdext
import gdext/classes/gdNode2D

type AgentNim* {.gdsync.} = ptr object of Node2D
  velocity: Vector2
  max_speed: float32
  damping: float32
  screen_size: Vector2

method physics_process(self: AgentNim; delta: float64) {.gdsync.} = 
  # Apply damping
  self.velocity = self.velocity * (1.0 - self.damping * float32 delta)
  
  # Update global position based on velocity
  self.position = self.position + (self.velocity * float32 delta)

  # Screen wrapping (optional, but keeps agents in view)
  if self.screen_size != Vector2.Zero: # Check against zero vector
    self.position = self.position.clamp(Vector2.Zero, self.screen_size)
  
  # Rotate towards the velocity direction
  if self.velocity.lengthSquared() > 0.001: # Use lengthSquared for efficiency
    self.rotation = self.velocity.angle() # Set rotation based on velocity angle

proc applySeparationForce*(self: AgentNim; force: Vector2; delta: float64) =
  # Simple acceleration model: velocity change is proportional to force
  self.velocity = self.velocity + (force * float32 delta)
  # Clamp velocity to max speed
  self.velocity = self.velocity.limitLength(self.max_speed)

When I build, I'm given an error:
Error: type mismatch: got 'float32' for 'arctan2(self[1], self[0])' but expected 'Radian[system.float32]' for the line self.rotation = self.velocity.angle()

I've tried to force cast such as: Radian[float32](self.velocity.angle()), Radian(self.velocity.angle()) seems to not work. Anyone have a similar case?

[panno8M]

There seems to be a deficiency in the gdext math library. I'll update it. Until then, please add the following after the import statement to work around it.

import std/math

func angle*[T: SomeFloat](self: Vector[2, T]): T =
  arctan2(self.y, self.x)

[panno8M]

Fixed: #226

Installing v0.11.0 should work with your code as is.

[guntur-ctech]

Thanks @panno8M for the support and update!