So I'm trying to figure out how to make a bullet class move from character to mouse click and if it hits a monster it will do damage to a monster. I've figured out how to calculate the mouse position and character position. It has been a while since ive been in a math class.
i'm using pygame, python 3.4
A possible solution could be to find the slope of the line between the point of origin(where you are shooting the bullet from) and the location of the mouse click. If you are storing the bullet's x and y values you can then use the slope to change those values every clock tick depending on the speed of the bullet or however you've got it working.
Ex. If the slope of the line is 2/5, every tick you change the bullet's y by 2 and the bullet's x by 5.
I think this may work, or at least may be close to what you are looking for.
Python, Shooting from Character Position to Mouse position on Mouseclick