Pygame Tutorial #6 - Enemies

Key Takeaways

[Music] hey guys and welcome back to another YouTube video so in today's video I'm gonna be continuing with the six video in my Python programming series and I'm just gonna give you a quick sneak peek on what's gonna be happening in this tutorial pretty much we're just gonna be creating an enemy on the screen just like the description or the title says that's able to walk around like this now I know this seems simple for something that's probably gonna be about a 12 to 15 minute video but this is more complicated than it looks and obviously we have the animation going so everything looks good and he's changing velocities as he hits each point so we're gonna put him on a path and he's gonna be able to move that path so that could be the path could be here could be here to here it's variable meaning it can change so that's what this tutorial is gonna be make sure you stick around to the end if you want to learn how to do this and since we're using images I just want to direct our attention to the github here quickly so if you haven't seen already I have a github for this series where I post all the images and all the tutorial files I started at 3 just because the first two were pretty basic if you scroll all the way down to the bottom so what actually happened is you're gonna get to this page if you click on the link in the description click on game scroll all the way down to the bottom these are all the tutorial files if you want to download them if you want to look at them for reference and then all of the images are in here so if you actually want to download these files you click clone or download and click download zip file and it's gonna download all of it onto your computer from there you're gonna drag all of these images so like from the top here all the way down to r9e into your what do you call it into your game folder directory wherever you have your Python files stored and then you're gonna be able to do this tutorial so make sure you do that if you want to use these sprites if not then you're just gonna have to load your sprites in by yourself hopefully you can figure that out and pretty much what I've done is I've named for example we have 11 images for our enemy moving left and moving right so I've done like L 10 e L 11 each meaning left 11th image and all right so that's the github if you guys haven't been there go check it out if you need to and yeah whatever okay so let's get right into this tutorial so our game here remember from last time right now oops this is a different game that I'm showing what am i doing that for um sorry okay so we got into our tutorial here you remember from last time we have our little guy jumps up and down moves around the screen now we're gonna create the enemy so the first thing we need to do when we want to create the enemy is oops I've accidentally closed this game again is we need to create a class so that we can then work out of that class so I've already done this I was done class and then enemy and it inherits from object and then I've created two class attributes here don't have to worry about what that means just write variables that look like this in your class now I've already loaded up all the images so I have r1 e r2 e all the way up to or 11 E and L 11 e into their names here so walk right walk left and you just do that at the top your class and then after that you can define your initialization function like so now you don't have to understand exactly how these class attributes work just write them in like this and we'll get to them later so we're just going to create our initialization here so we need X Y width height and then we're gonna create another one here that's new it's gonna be called end and I'm gonna go over that in a second so do self taught x equals x self the why cuz why wow I can't type and we'll do so filled with equals width and so on until we finish all of the variables and then we'll add our constants and I myself thought and equals ends like that so now we're gonna add our self dot walk count this is what's gonna be responsible for counting our sprites and what image Ron and we need self dot Val and that's gonna be equal to we'll start with three so now we need to create our draw function our methods sorry we're gonna do define draw inside here we're gonna take self and window and then we're gonna write pass in here is we're gonna get back to and then we're gonna create our note another method called move and then here we're gonna do self and that's all we need just self in there alright so I know I've just whizzed through that it just because we've already done this a bunch of times so I figured we can go fast through this part what we're gonna do here is we're gonna create our enemy now our enemy's gonna move on a set path so like I showed you before it moves from left to right and then left and then right and pretty much moves between two coordinate points so ours is gonna move in one dimension meaning it's only gonna move across the x-axis now if you wanted to move this up or down you would just change the Y value rather than changing the x value okay whereas for us since we're moving X we're just gonna be create adding to the x value or subtracting to the x value depending on where our enemy is so I want to run this program already I have another file where it's already coded you can see once he gets to a coordinate point so about where my mouse is he turns around he changes directions now to change directions he needs to change velocities so to do that we're gonna be multiplying the velocity by negative one and so on and I'm gonna get into that now so this is gonna be our move method here now what this move method is gonna be responsible for is every time we try to draw the character we're gonna move we're gonna move the character so we're gonna do self-thought move in here so we don't forget every time we draw we're gonna first move and then we're gonna draw the character now I just need to add another variable appear it's gonna be so called self that path and it's going to equal self dot X and self dot end now this represents where we're starting and where we're ending and these are just the x coordinates so that we can keep track of them when I'm checking them down in the move method so we go into the move method here and we're gonna start by saying if our character has a velocity that's positive so pretty much if self-thought velocity is greater than zero that means we are moving right so we're going right we're adding to the velocity then what do we have to do well we have to check if he is about to move past the point that we wanted to stop at so we're if self that X is greater than or actually we're gonna check if it's less than so we know if it's less than and then self thought path and since we're moving to the right we know this coordinate is gonna be to the right of whatever what do you call it our character is moving up if it is less than self thought path and then from there we just do one like this because we're accessing this element here so add a little brain fart there - self thought velocity or plus actually so this way we can tell sorry I need to change this to over here plus self dot velocity so that we see that if we add to the velocity of this x-coordinate here if it's less than the coordinate that we can't go past then we will allow our character to move so then we will do these self thought X plus equals self dot velocity like that I hope that makes sense now if we are already past this coordinate so our X is greater than or we are about to be greater than then we need to change directions so to change directions like I mentioned before we're just going to multiply our velocity by negative one but therefore flipped us 180 degrees and moving us in the opposite direction then what we're gonna do is going to set our walk count back down to zero like that and that's all for that now let's create our else statement because if our velocity is negative so it's not greater than zero then we need to check if our self dot X it - be self double I'll see this time is greater than in this instance what's gonna be self dot path one like this they're not one zero straight so this is exactly where we started from we're moving negative so we want to make sure that we don't go past that if we're not moving past that again will change our X so your self thought X plus equals self novel now you might think well we should probably subtracting and removing left but our velocity is gonna be negative if we've changed directions move left so if your negative you're really just subtracting that number so that's fine and then same thing in the else statement here you're just gonna copy exactly what we have here oops don't know why I deleted it like that so we have self dot Val equals self sub L times negative one again changing the directions to negatives make a positive we're gonna be moving right again and self to walk count equals zero we can get rid of this pass and that's all we need for our move method like that all right so now after we've done that we're gonna move back into our draw here and this is where we're gonna determine whether we're drawing an image to the left or whether we're drawing an image to the right and how that animation is going to work similar to what we've done in the player class up here you're just going to be a little bit different so if you remember in our player class so actually let's go up here for a second we have 27 as our maximum walk count now once that walk count gets past 27 we reset it back down to zero so we can continue the animation now since we have 11 images actually rather than nine in our enemy so moving right or left we need to change this slightly so we're gonna do if self thought walk count is less or plus one is less than or equal to 33 like this then we're going to new self dot walk out Wow equals zero sorry my typing is absolutely horrible now if that's not the case or after we check that then again we're gonna be checking to see whether we're moving left or right so rather than having like a self thought or having a self dot right variable a self thought left variable or attribute whatever we want to just use the velocity because we know if our velocities pause that we're moving right if our velocity is negative roofing left right so if our velocity is greater than zero that means we're moving right so if it's greater than zero we're all we're gonna do is we're gonna pull it to the screen the images again it's a wind-up lit and then we want our image so we're gonna do self and this is where these come in handy you just have to use self to access these all right so we're gonna do self dot walk right so we're moving right and then in here square brackets and self-taught walk count and then integer division 3 again because we want to make sure it's not looking like we're moving too fast then we need our coordinates so we'll do self dot X and self del Y and then we need to increment our walk count so we'll do walk count plus equals one like that now else so if we're not moving left we've all right we're not moving right we must be with left I'm just gonna copy this and then we can edit in here so we're just gonna change this simply to left and I think that's all we need to do so now that will actually get rid of this pass here now that we've had the draw method we have the move method what we need to do is we need to create an instance of our enemy so it right now if I show you if I run the program since we haven't created an instance we still he's not on the screen we don't see him he's not moving around we need to first create the instance of him so just like we created the man instance down here near our main loop we're gonna do the same thing I'm just gonna call this goblin and he is an instance of enemy he's gonna start at what x-coordinate we'd like maybe 100 for 10 again and then would be 64 by 64 and where do we want to end so what x-coordinate the path that we wanted to end up let's maybe do 450 and there we go we create an incident instance of him now that we've created that instance we need to dry so goblin draw on the window and let's test this out we have an issue named Bell is not defined ah error that I've ran into here we need to just put self though though here my bed and let's see if it works now walk count reference for assignment I always forget myself so you don't know so just make sure you guys have yourselves here because I forgot them and everything looks good let's test it out there we go we see we have a little goblin man moving around but it doesn't look like everything's working properly right his feet aren't moving so what could the issue be here now I think the issue is something to do with our walk count whether we're not incrementing it properly or ah this is the issue less than needs to be changed to greater than what I've just fixed here is the fact that we were saying that if self thought walk count is plus one is less than 33 which it always is then it's just gonna set it to zero so he wasn't changing the image ever so what we needed to do there is we needed to set this to greater than so that that's not happening sorry guys my mistake there let's run this and there we go we see our goblin running around the screen and when you get to the end coordinate he changes direction and you can see has a nice little punching thing there and so what we're gonna do with this in the next tutorial is gonna be doing collision with our player so if he hits the player it's gonna lose points and then our player he has these bullets right that he can shoot if he hits the Goblin call him do you think I start flashing or the players gonna gain points we can figure that out in the next tutorial so sorry about that little issue there guys but if you enjoyed the video please leave a like and subscribe and I will see you again in the next one [Music]