example_2d_space.py

import math
import pyglet

class Coordinate:
	x = 0
	y = 0

	def __repr__(self):
		return f'Coordinate(x: {self.x}, y: {self.y})'

window = pyglet.window.Window()
main_batch = pyglet.graphics.Batch()
player_image = pyglet.image.load('player.png')
player_image.anchor_x = player_image.width // 2
player_image.anchor_y = player_image.height // 2
player = pyglet.sprite.Sprite(player_image, x=100, y=200, batch=main_batch)
mouse = Coordinate()

label_delta = pyglet.text.Label('', x=10, y=window.height-20, batch=main_batch)
label_tangent = pyglet.text.Label('', x=10, y=window.height-40, batch=main_batch)
label_degrees = pyglet.text.Label('', x=10, y=window.height-60, batch=main_batch)

keys = {}
angle = 0

def delta(source, destination):
	# Step 2
	result = Coordinate()
	result.x = destination.x - source.x
	result.y = destination.y - source.y

	return result

def angle_in_radiance(delta_y, delta_x):
	# Step 3
	return math.atan2(delta_y, delta_x)

def radiance_to_degrees(radiance):
	# Step 4
	return (radiance * (180/math.pi) + 360) % 360

def draw_line_between(source, destination):
	pyglet.graphics.draw(2, pyglet.gl.GL_LINES, 
		("v2f", (source.x, source.y, destination.x, destination.y))
	)

def move(object, angle, distance):
	# Convert the angle to a cosine and sine
	# https://setosa.io/ev/sine-and-cosine/
	# (Essentially a multiplier in a diction/space)
	x_multiplier = math.cos(((angle)/180)*math.pi)
	y_multiplier = math.sin(((angle)/180)*math.pi)

	# Multiply the x and y multipliers with the distance you want to travel
	object.x += x_multiplier * distance
	object.y += y_multiplier * distance

@window.event
def on_mouse_motion(x, y, dx, dy):
	# Step 1, gether the data
	mouse.x = x
	mouse.y = y

@window.event
def on_mouse_press(*args, **kwargs):
	global angle # Put it here to emphasis that it's a global variable
	move(player, angle, distance=5) # 50 pixels

@window.event
def on_draw():
	global angle

	window.clear()

	# Step 2
	delta_result = delta(player, mouse)
	# Step 3
	tangent = angle_in_radiance(delta_result.y, delta_result.x)
	# Step 4
	angle = radiance_to_degrees(tangent)

	# Debug output
	label_delta.text = 'Delta: ' + str(delta_result)
	label_tangent.text = 'Tangent: ' + str(tangent)
	label_degrees.text = 'Degrees: ' + str(int(angle))
	draw_line_between(player, mouse)

	# Use the result
	player.rotation = 0-angle   # Degrees are counted counter clockwise, so we have to adjust for it.

	# Draw it
	main_batch.draw()

pyglet.app.run()

player.png

Helper class: https://github.com/Torxed/Scripts/blob/master/python/2d.py