Welcome!
This is the community forum for my apps Pythonista and Editorial.
For individual support questions, you can also send an email. If you have a very short question or just want to say hello — I'm @olemoritz on Twitter.
Help me find a way to make the lasers fire in a certain direction.
-
Your code was untestable, because you provided code with syntax errors, that could not even run. You will probably get better results asking for help when it seems like you have even tried your code, and have made any attempt to diagnose it. If you are getting an error, you should mention that.
I did get your code to run, and behave in a logical way, as follows:
-
Moved the lasers update loop to the right indent level (you dont want to do that for every touch), and remived all of the if statements, since they were garbage and not properly indented
2) Used self.Player.rotation to define a persistent direction of last motion. Had you gotten through your syntax error, you would have noticed another immediate error, that direction was not defined, because of course, it is a local variable that only is defined during a touch, and so when you lift your finger off the direction button, it will fail. Presuamably what you want is for the direction buttons to rotate the player, and laser direction based on player rotation. Here it helps to define a player sprite that has some directionality, like one of the spc:PlayerShipxxx, but once you choose a sprite, you will use 0, math.pi/2, math.pi, and math.pi*3/2 as your four directions. You likely will want your anchor point to be 0.5,0.5. By trial and error, you will figure out which rotation is appropriate for each drirection.
3) Using player rotation now lets you set the laser rotation equal to Player.rotation. That takes care of drawing the laser properly. -
I found it convienent to compute a Vector2
direction = Vector2(-math.sin(new_laser.rotation), math.cos(new_laser.rotation))
Depending in how you define your rotations, you might need to swap the sin and cos, and or change signs, if the laser moves in the wrong direction. how you define those rotations depend on the sprite you use for your player.
Then, you can simply offset the position by a scaled version of this,
l.position += direction*75
or
new_laser.position = self.Player.position + direction*6
etc
Vector2 is very useful like that. You could also use it to simplify your movement code in the same way
-
-
other comments:
You are spawning lasers at 60 per second when the button is touched, then moving them at 4500 pixels per second. Consider storing a variable that has the last time a laser was fired, then check self.t is greater than that time plus some lock out time. Or, use touch_began only as the method for firing lasers, rather than update (which gets called at 60 fps), so feverishly tapping the button can make lasers appear faster.You can also use run_action with an Action.Sequence consisting of Action.move_by the laser by a few thousand pixels in the desired direction over some time that defines the speed, then removes it from the scene. The animation looks much smoother when you use Actions
-
Whenever, I press the laser button, the laser just goes to far left-hand side and goes up no matter what. I think its due to the fact that I haven’t implemented your tips correctly however.
from scene import * import math A = Action() #Setting up background colour for the entire scene class Game(Scene): def setup(self): self.bg = SpriteNode('spc:BackgroundBlack') self.lasers = [] #Creating the player self.Player = SpriteNode('shp:RoundRect') self.Player.color = ("cyan") self.Player.anchor_point = (0.5, 0.5) self.Player.position = (512, 400) self.Player.rotation = 0.0 self.add_child(self.Player) self.UpCrtl = SpriteNode('iow:arrow_up_b_32') self.UpCrtl.x_scale = 3.5/1.0 self.UpCrtl.y_scale = 3.5/1.0 self.UpCrtl.alpha = 0.5 self.UpCrtl.position = (175, 295) self.add_child(self.UpCrtl) self.DownCrtl = SpriteNode('iow:arrow_down_b_32') self.DownCrtl.x_scale = 3.5/1.0 self.DownCrtl.y_scale = 3.5/1.0 self.DownCrtl.alpha = 0.5 self.DownCrtl.position = (175, 130) self.add_child(self.DownCrtl) self.RightCrtl = SpriteNode('iow:arrow_right_b_32') self.RightCrtl.x_scale = 3.5/1.0 self.RightCrtl.y_scale = 3.5/1.0 self.RightCrtl.alpha = 0.5 self.RightCrtl.position = (250, 212.5) self.add_child(self.RightCrtl) self.LeftCrtl = SpriteNode('iow:arrow_left_b_32') self.LeftCrtl.x_scale = 3.5/1.0 self.LeftCrtl.y_scale = 3.5/1.0 self.LeftCrtl.alpha = 0.5 self.LeftCrtl.position = (100, 212.5) self.add_child(self.LeftCrtl) #The button for shooting self.laserButton = SpriteNode('shp:Circle') self.laserButton.color = ('gray') self.laserButton.x_scale = 3/1 self.laserButton.y_scale = 3/1 self.add_child(self.laserButton) self.laserButton.position = (1000, 212.5) #The score label self.score_label = LabelNode(text='Score: 0') self.score_label.anchor_point = (0, -300) self.score_label.position = (20, 718) self.score_label.font = ('Arial Rounded MT Bold', 30) self.add_child(self.score_label) #Movement code. def update(self): for touch in self.touches.values(): if touch.location in self.LeftCrtl.bbox: new_x = self.Player.position.x - 5 self.Player.rotation = math.pi*3/2 if new_x >= 0 and new_x <= 1100: self.Player.position = (new_x, self.Player.position.y) if touch.location in self.RightCrtl.bbox: new_x = self.Player.position.x + 5 self.Player.rotation = math.pi/2 if new_x >= 0 and new_x <= 1100: self.Player.position = (new_x, self.Player.position.y) if touch.location in self.UpCrtl.bbox: new_y = self.Player.position.y + 5 self.Player.rotation = 0.0 if new_y >= 0 and new_y <= 800: self.Player.position = (self.Player.position.x, new_y) if touch.location in self.DownCrtl.bbox: new_y = self.Player.position.y - 5 self.Player.rotation = math.pi if new_y >= 0 and new_y <= 800: self.Player.position = (self.Player.position.x, new_y) if touch.location in self.laserButton.bbox: new_laser = SpriteNode('spc:LaserBlue6') direction = Vector2(-math.sin(new_laser.rotation), math.cos(new_laser.rotation)) self.add_child(new_laser) self.lasers.append(new_laser) for l in self.lasers: l.position += direction*75 if __name__ == '__main__': run(Game(), LANDSCAPE, show_fps=True) -
random, turtle, and ui are imported but not used which slows down startup and uses more memory.
A = Action() is created but not used which slows down startup and uses more memory.
self.laserButton = SpriteNode('shp:Circle') is created twice which slows down startup, uses more memory, and makes it confusing which instance is being clicked on.
Please reread and follow @JonB advise above.
-
If you want help, you need to explain what the problem is, what you have tried. For instance you might start by saying "help, my lasers now don't even spawn in the right position" to which someone might ask (maybe even you), gee, did you remember to set the laser position when you spawned it?
Or you might be wondering why the laser w only move when you are touching the button. In which case one could respond that you maybe didn't fix the indentation as previously mentioned. The act of typing out "for some reason my lasers only move when I am touching the fire button" might make you look at the code that moves your lasers, or look at the code that runs when the fire button is pressed.
You might be wondering "hey, I updated the code to use
direction, but all lasers seem to use the direction from when the button was pressed", which would allow someone to point out that if you want to use it in your laser update loop, it needs to be defined inside said loop (using the rotation of the looped laser object), or store it as an attribute of the laser object.I would encourage you to try to understand your own code before asking for help. Then you can be specific about what you tried, what debugging you added in to understand the program flow, or what you think should be happening vs what is actually happening.
-
Whenever I press the shoot button, lasers fire down on the far left-hand side of the screen, and only go up. I am not getting any immediate errors, so I am investigating into the math.
-
I think its due to the fact that I haven’t implemented your tips correctly however.
-
I have assigned so the new_laser.rotation is = to the player rotation, this results in lasers popping on sides, not the right sides because I probably have to switch the math.pi equations around, but they are not moving.
-
Move the for l in self.lasers loop to the proper indentation level. This should not be inside any of the touch handling code.
You will then use the
l.rotationto set the motion direction.Also, you will eventually need code that deletes lasers once they are off screen ( in that loop, check if laser.bbox is in self.bbox)
-
Um, sorry? I don’t really understand. I have properly indented the for l in self.lasers part, I don’t know how to add l.rotation to set motion direction.
-
Post your code. The last version you posted had the laser motion code INSIDE the touch handling code, which means the code would only execute when the fire button was being pressed.
-
from scene import * import math A = Action() #Setting up background colour for the entire scene class Game(Scene): def setup(self): self.bg = SpriteNode('spc:BackgroundBlack') self.lasers = [] #Creating the player self.Player = SpriteNode('shp:RoundRect') self.Player.color = ("cyan") self.Player.anchor_point = (0.5, 0.5) self.Player.position = (512, 400) self.Player.rotation = 0.0 self.add_child(self.Player) self.UpCrtl = SpriteNode('iow:arrow_up_b_32') self.UpCrtl.x_scale = 3.5/1.0 self.UpCrtl.y_scale = 3.5/1.0 self.UpCrtl.alpha = 0.5 self.UpCrtl.position = (175, 295) self.add_child(self.UpCrtl) self.DownCrtl = SpriteNode('iow:arrow_down_b_32') self.DownCrtl.x_scale = 3.5/1.0 self.DownCrtl.y_scale = 3.5/1.0 self.DownCrtl.alpha = 0.5 self.DownCrtl.position = (175, 130) self.add_child(self.DownCrtl) self.RightCrtl = SpriteNode('iow:arrow_right_b_32') self.RightCrtl.x_scale = 3.5/1.0 self.RightCrtl.y_scale = 3.5/1.0 self.RightCrtl.alpha = 0.5 self.RightCrtl.position = (250, 212.5) self.add_child(self.RightCrtl) self.LeftCrtl = SpriteNode('iow:arrow_left_b_32') self.LeftCrtl.x_scale = 3.5/1.0 self.LeftCrtl.y_scale = 3.5/1.0 self.LeftCrtl.alpha = 0.5 self.LeftCrtl.position = (100, 212.5) self.add_child(self.LeftCrtl) #The button for shooting self.laserButton = SpriteNode('shp:Circle') self.laserButton.color = ('gray') self.laserButton.x_scale = 3/1 self.laserButton.y_scale = 3/1 self.add_child(self.laserButton) self.laserButton.position = (1000, 212.5) #The score label self.score_label = LabelNode(text='Score: 0') self.score_label.anchor_point = (0, 0) self.score_label.position = (10, 790) self.score_label.font = ('Arial Rounded MT Bold', 30) self.add_child(self.score_label) #Movement code. def update(self): for touch in self.touches.values(): if touch.location in self.LeftCrtl.bbox: new_x = self.Player.position.x - 5 self.Player.rotation = math.pi*3/2 if new_x >= 0 and new_x <= 1100: self.Player.position = (new_x, self.Player.position.y) if touch.location in self.RightCrtl.bbox: new_x = self.Player.position.x + 5 self.Player.rotation = math.pi/2 if new_x >= 0 and new_x <= 1100: self.Player.position = (new_x, self.Player.position.y) if touch.location in self.UpCrtl.bbox: new_y = self.Player.position.y + 5 self.Player.rotation = 0.0 if new_y >= 0 and new_y <= 800: self.Player.position = (self.Player.position.x, new_y) if touch.location in self.DownCrtl.bbox: new_y = self.Player.position.y - 5 self.Player.rotation = math.pi if new_y >= 0 and new_y <= 800: self.Player.position = (self.Player.position.x, new_y) if touch.location in self.laserButton.bbox: new_laser = SpriteNode('spc:LaserBlue6') new_laser.rotation = self.Player.rotation direction = Vector2(-math.sin(new_laser.rotation), math.cos(new_laser.rotation)) self.add_child(new_laser) self.lasers.append(new_laser) for l in self.lasers: l.position += direction*75 if __name__ == '__main__': run(Game(), LANDSCAPE, show_fps=True) -
Can
if touch.location in self.DownCrtl.bbox: new_y = self.Player.position.y - 5 self.Player.rotation = math.pi if new_y >= 0 and new_y <= 800: self.Player.position = (self.Player.position.x, new_y)be simplified to
if touch.location in self.DownCrtl.bbox: self.Player.rotation = math.pi if 0 <= new_y <= 800: self.Player.position.y -= 5 -
@BurntRice okay, so
l.position += direction*75Let's think about this for a minute. Where have you defined
direction? Remember, the goal here in the movement code is to figure out the direction for EACH laser that you are moving. So, you need to figure out the direction Vector2 based on each laser's rotation. -
Perhaps
for l in self.lasers: l.position += direction*75needs to be indented under the
if touch.location in self.laserButton.bbox:block wheredirectionis defined. -
No. Trying the Socratic method to get him to think about his own code...
This would be simpler if the touch code and laser update code were their own functions, as they are completely independent. The fact that he shares a
directionvariable name is what is confusing him.The touch code creates a laser. The laser created is spawned, and the code that sets the rotation and initial offset.
The code that moves the lasers is completely separate (one needn't have touch code at all to move laser objects). Lasers move even when buttons are not touched. So, how can you figure out what direction a given laser should travel?
-
I’ve made it so my laser shoots in the direction that I want it to, but, they are not moving. Once one laser pops up, the next one goes 75 pixels ahead, for ad infinitum. I don’t know if this is because of where I indented my direction value, but I don’t think so as that is mostly for rotation; nothing about moving forward etc.
-
So you have code which is moving your laser, but it is only running once?
Go back and look at all of your code to see if your indentation is correct. If you want laser movement code to run every update cycle, and it isn't, there must be some control code (if, for, with, while, etc ) that is preventing it from running.
What will help you in this case is to break your update function into functions that you call, so that you can better follow the program flow. Once an indented section of code gets to be longer than a screenfull, that's a good indication that you might need a function.
For instance, if each button had it's own method. Or, if all of your touch handling had it's own method. Then your update method would be easier for you to follow:
def update (self): handleTouches(self) moveLasers(self) checkCollisions(self) spawnEnemies(self) -
I have been looking for quite a bit, and I’m really blind, but I can’t find any indentation errors.
from scene import * import math A = Action() #Setting up background colour for the entire scene class Game(Scene): def setup(self): self.bg = SpriteNode('spc:BackgroundBlack') self.lasers = [] #Creating the player self.Player = SpriteNode('spc:Fire1') self.Player.color = ("cyan") self.Player.anchor_point = (0.5, 0.5) self.Player.x_scale = 2/1.0 self.Player.y_scale = 1.5/1.0 self.Player.position = (512, 400) self.Player.rotation = 0.0 self.add_child(self.Player) self.UpCrtl = SpriteNode('iow:arrow_up_b_32') self.UpCrtl.x_scale = 3.5/1.0 self.UpCrtl.y_scale = 3.5/1.0 self.UpCrtl.alpha = 0.5 self.UpCrtl.position = (175, 295) self.add_child(self.UpCrtl) self.DownCrtl = SpriteNode('iow:arrow_down_b_32') self.DownCrtl.x_scale = 3.5/1.0 self.DownCrtl.y_scale = 3.5/1.0 self.DownCrtl.alpha = 0.5 self.DownCrtl.position = (175, 130) self.add_child(self.DownCrtl) self.RightCrtl = SpriteNode('iow:arrow_right_b_32') self.RightCrtl.x_scale = 3.5/1.0 self.RightCrtl.y_scale = 3.5/1.0 self.RightCrtl.alpha = 0.5 self.RightCrtl.position = (250, 212.5) self.add_child(self.RightCrtl) self.LeftCrtl = SpriteNode('iow:arrow_left_b_32') self.LeftCrtl.x_scale = 3.5/1.0 self.LeftCrtl.y_scale = 3.5/1.0 self.LeftCrtl.alpha = 0.5 self.LeftCrtl.position = (100, 212.5) self.add_child(self.LeftCrtl) #The button for shooting self.laserButton = SpriteNode('shp:Circle') self.laserButton.color = ('gray') self.laserButton.x_scale = 3/1 self.laserButton.y_scale = 3/1 self.add_child(self.laserButton) self.laserButton.position = (1000, 212.5) #The score label self.score_label = LabelNode(text='Score: 0') self.score_label.anchor_point = (0, 0) self.score_label.position = (10, 790) self.score_label.font = ('Arial Rounded MT Bold', 30) self.add_child(self.score_label) #Movement code. def update(self): for touch in self.touches.values(): if touch.location in self.LeftCrtl.bbox: new_x = self.Player.position.x - 5 self.Player.rotation = math.pi/2 if new_x >= 0 and new_x <= 1100: self.Player.position = (new_x, self.Player.position.y) if touch.location in self.RightCrtl.bbox: new_x = self.Player.position.x + 5 self.Player.rotation = math.pi*3/2 if new_x >= 0 and new_x <= 1100: self.Player.position = (new_x, self.Player.position.y) if touch.location in self.UpCrtl.bbox: new_y = self.Player.position.y + 5 self.Player.rotation = 0.0 if new_y >= 0 and new_y <= 800: self.Player.position = (self.Player.position.x, new_y) if touch.location in self.DownCrtl.bbox: new_y = self.Player.position.y - 5 self.Player.rotation = math.pi if new_y >= 0 and new_y <= 800: self.Player.position = (self.Player.position.x, new_y) if touch.location in self.laserButton.bbox: new_laser = SpriteNode('shp:Circle') new_laser.x_scale = 0.25/1.0 new_laser.y_scale = 0.25/1.0 new_laser.position = self.Player.position new_laser.rotation = self.Player.rotation direction = Vector2(-math.sin(new_laser.rotation), math.cos(new_laser.rotation)) self.add_child(new_laser) self.lasers.append(new_laser) for l in self.lasers: l.position += direction*75 if __name__ == '__main__': run(Game(), LANDSCAPE, show_fps=True) -
Think about what should happen when you lifr your finger. Remember,
updategets called 60 times per second.Do you want the existing lasers to keep moving? Or move only when your finger is down, and freeze when your finger is up.
I would suggest rewriting your update function as follows, to make it easier for you to follow:
def update(self): self.handle_button_presses() self.move_lasers()Your touch handling code then moves to one method, and other game logic moves to their own functions, and get called from
update. For example, eventually you might be moving enemies or asteroids or the map. You might be spawning enemies at certain intervals, which would also be it's own method. Thus, you would create aspawn_enemies, andmove_enemiesmethods, maybe ascroll_mapif this is scroller type game, perhaps acheck_collisionswhich checks if the player hit any obstacles or enemies, etc. You should be able to write your entireupdatemethod using dummy methods that sort of lay out what you need to work in, and can implement the methods one at a time, since they should all be mostly independent of each other, just depending on a common set of attributes or positions.
