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    Sprite animation from sprite sheet at 8 FPS?

    Pythonista
    sprite spritesheet game scene module animation
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    • pulbrich
      pulbrich last edited by

      Move the sprite changing code to the update method of your scene; and do the change only when enough time passed since the last change.

      Scene.update()
      Performs any scene-specific updates that need to occur before scene actions are evaluated.

      Vile 1 Reply Last reply Reply Quote 0
      • JonB
        JonB last edited by

        Take a look at the Game Tutorial in the examples folder... I think the second or third installment, where it shows how to animate walking. As stated above, it should be called from update -- or, you could create an Action.sequence consisting of ab Action.wait, and an Action.call, which calls a method you create that sets the texture to the next one. (add a texture_idx and texture_list as attributes of your SpriteNode, so you can easily cycle through them). Then wrap the sequence in an Action.repeat, set to repeat forever.

        Or, you could simplify even more, and have a single Action.call (wrapped in a repeat), where you include the duration parameter. The duration would be the time it takes to execute the entire sequence -- within the call, you'd check if progress*len(textures) is different than your current index, and if so, you'd set the texture_idx to that value, and then set the texture . That eliminates the wait, and might allow you to use different timing nodes (though maybe not)

        Vile 2 Replies Last reply Reply Quote 0
        • Vile
          Vile @pulbrich last edited by

          @pulbrich, could you give an example of how to check that the correct amount of time has passed?

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          • Vile
            Vile @JonB last edited by

            @JonB, I’ve already looked at the game tutorial, where it showed how to animate a walking sequence. However, that method only works when the sprite is changing its position in pixels on the screen, so it will not work for my sprite. This is because my sprite’s position is constantly at the centre of the screen.

            The effect I’m trying to achieve is basically a GIF with a customisable frame speed, which is permanently in exactly the same position at the centre of the screen.

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            • Vile
              Vile @JonB last edited by

              @JonB, I’ve also never used Action.wait before, so I’d appreciate an example of this, thanks.

              Remember, I’m still a noob here lol

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              • pulbrich
                pulbrich last edited by

                @Vile :

                import time #this module is needed to get the system time
                

                In your set-up code:

                self.last_update = time.process_time()
                

                In your update method:

                current_time = time.process_time()
                if current_time - self.last_update > 0.125:
                	self.last_update = current_time
                	modify_the_sprite
                
                Vile 1 Reply Last reply Reply Quote 1
                • Vile
                  Vile @pulbrich last edited by

                  @pulbrich

                  I tried your method, but it seems that anything I put into the update function doesn’t get used...

                  Here’s the updated code:

                  from scene import *
                  import time
                  
                  sprite_sheet = [
                  Texture('IMG_0227.png').subtexture(Rect(0,0,0.25,1)),
                  Texture('IMG_0227.png').subtexture(Rect(0.25,0,0.25,1)),
                  Texture('IMG_0227.png').subtexture(Rect(0.5,0,0.25,1)),
                  Texture('IMG_0227.png').subtexture(Rect(0.75,0,.25,1)),
                  ]
                  
                  class MyScene (Scene):
                  	def setup(self):
                  		self.screen="game"
                  		self.background_color = 'black'
                  		self.last_update = time.process_time()
                  		self.sprite = SpriteNode(sprite_sheet[0],
                  		scale = 1,
                  		position = self.size / 2,
                  		parent = self)
                  		self.add_child(self.sprite)
                  		n=0
                  		
                  		def update(self):
                  			current_time = time.process_time()
                  			if current_time - self.last_update > 0.125:
                  				self.last_update = current_time
                  				#modify_the_sprite
                  				self.sprite.texture=sprite_sheet[n]
                  				n=n+1
                  run(MyScene())
                  
                  1 Reply Last reply Reply Quote 0
                  • Vile
                    Vile last edited by

                    Wait it actually works, I just had the wrong indentation on the update function XD

                    Here’s the code:

                    from scene import *
                    import time
                    
                    sprite_sheet = [
                    Texture('IMG_0227.png').subtexture(Rect(0,0,0.25,1)),
                    Texture('IMG_0227.png').subtexture(Rect(0.25,0,0.25,1)),
                    Texture('IMG_0227.png').subtexture(Rect(0.5,0,0.25,1)),
                    Texture('IMG_0227.png').subtexture(Rect(0.75,0,.25,1)),
                    ]
                    
                    class MyScene (Scene):
                    	def setup(self):
                    		self.screen="game"
                    		self.background_color = 'black'
                    		self.last_update = time.process_time()
                    		self.sprite = SpriteNode(sprite_sheet[0],
                    		scale = 1,
                    		position = self.size / 2,
                    		parent = self)
                    		self.add_child(self.sprite)
                    		self.n=0
                    		
                    	def update(self):
                    		#self.sprite.texture=sprite_sheet[1]
                    		current_time = time.process_time()
                    		if current_time - self.last_update > 0.05:
                    			self.last_update = current_time
                    			#modify_the_sprite
                    			self.sprite.texture=sprite_sheet[self.n]
                    			self.n=self.n+1
                    			if self.n > 3:
                    				self.n=0
                    run(MyScene())
                    

                    Thanks a lot for your help!

                    1 Reply Last reply Reply Quote 0
                    • JonB
                      JonB last edited by

                      dont use time.process_time. instead use scene.t -- scene includes t which is the time since the start of the scene, and dt, which is the time since last update.

                      Vile 1 Reply Last reply Reply Quote 1
                      • Vile
                        Vile @JonB last edited by

                        @JonB, I tried using scene.t and scene.dt, but I can’t get it working...

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                        • pulbrich
                          pulbrich last edited by pulbrich

                          Instead of using the time function that I suggested, put Scene.t (mind the capital S)

                          CORRECTION: it is self.t (instance attribute), thanks @JonB

                          self.dt is not directly suitable for your case; it gives you the time lapsed since the last call to update().

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                          • JonB
                            JonB last edited by

                            I think it should be self.t.
                            it is an instance attribute, not a class attrib, if memory serves -- the time is incremented in the running scene only.

                            1 Reply Last reply Reply Quote 1
                            • cvp
                              cvp last edited by

                              Following @JonB advice, this works

                              .
                              .
                              .
                                      self.last_t = self.t
                                      
                                  def update(self):
                                      #self.sprite.texture=sprite_sheet[1]
                                      if (self.t-self.last_t) > 0.05:
                                          #modify_the_sprite
                                          self.last_t = self.t
                              .
                              .
                              .
                              
                              1 Reply Last reply Reply Quote 1
                              • Vile
                                Vile last edited by

                                @JonB and @cvp, thanks once again! It seems to work in the way I expected now.

                                It seems that scene.t uses a different time frame from time.process_time, because with the same number value, the animations appear to go at different speeds.

                                cvp 1 Reply Last reply Reply Quote 0
                                • cvp
                                  cvp @Vile last edited by

                                  @Vile thank only @jonb 😀

                                  1 Reply Last reply Reply Quote 0
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