112 lines
3.6 KiB
Python
112 lines
3.6 KiB
Python
|
'''
|
||
|
|
FBO example
|
||
|
|
===========
|
||
|
|
|
||
|
|
This is an example of how to use FBO (Frame Buffer Object) to speedup graphics.
|
||
|
|
An Fbo is like a texture that you can draw on it.
|
||
|
|
|
||
|
|
By default, all the children are added in the canvas of the parent.
|
||
|
|
When you are displaying thousand of widget, you'll do thousands of graphics
|
||
|
|
instructions each frame.
|
||
|
|
The idea is to do this drawing only one time in a Fbo, and then, draw the Fbo
|
||
|
|
every frame instead of all children's graphics instructions.
|
||
|
|
|
||
|
|
We created a FboFloatLayout that create his canvas, and a Fbo.
|
||
|
|
After the Fbo is created, we are adding Color and Rectangle instruction to
|
||
|
|
display the texture of the Fbo itself.
|
||
|
|
The overload of on_pos/on_size are here to update size of Fbo if needed, and
|
||
|
|
adapt the position/size of the rectangle too.
|
||
|
|
|
||
|
|
Then, when a child is added or removed, we are redirecting addition/removal of
|
||
|
|
graphics instruction to our Fbo. This is why add_widget/remove_widget are
|
||
|
|
overloaded too.
|
||
|
|
|
||
|
|
.. note::
|
||
|
|
|
||
|
|
This solution can be helpful but not ideal. Multisampling are not available
|
||
|
|
in Framebuffer. We will work to add the support of it if the hardware is
|
||
|
|
capable of, but it could be not the same.
|
||
|
|
|
||
|
|
'''
|
||
|
|
|
||
|
|
|
||
|
|
# needed to create Fbo, must be resolved in future kivy version
|
||
|
|
from kivy.core.window import Window
|
||
|
|
|
||
|
|
from kivy.graphics import Color, Rectangle, Canvas
|
||
|
|
from kivy.graphics.fbo import Fbo
|
||
|
|
from kivy.uix.floatlayout import FloatLayout
|
||
|
|
from kivy.properties import ObjectProperty
|
||
|
|
|
||
|
|
|
||
|
|
class FboFloatLayout(FloatLayout):
|
||
|
|
|
||
|
|
texture = ObjectProperty(None, allownone=True)
|
||
|
|
|
||
|
|
def __init__(self, **kwargs):
|
||
|
|
self.canvas = Canvas()
|
||
|
|
with self.canvas:
|
||
|
|
self.fbo = Fbo(size=self.size)
|
||
|
|
Color(1, 1, 1)
|
||
|
|
self.fbo_rect = Rectangle()
|
||
|
|
|
||
|
|
# wait that all the instructions are in the canvas to set texture
|
||
|
|
self.texture = self.fbo.texture
|
||
|
|
super(FboFloatLayout, self).__init__(**kwargs)
|
||
|
|
|
||
|
|
def add_widget(self, *args, **kwargs):
|
||
|
|
# trick to attach graphics instruction to fbo instead of canvas
|
||
|
|
canvas = self.canvas
|
||
|
|
self.canvas = self.fbo
|
||
|
|
ret = super(FboFloatLayout, self).add_widget(*args, **kwargs)
|
||
|
|
self.canvas = canvas
|
||
|
|
return ret
|
||
|
|
|
||
|
|
def remove_widget(self, *args, **kwargs):
|
||
|
|
canvas = self.canvas
|
||
|
|
self.canvas = self.fbo
|
||
|
|
super(FboFloatLayout, self).remove_widget(*args, **kwargs)
|
||
|
|
self.canvas = canvas
|
||
|
|
|
||
|
|
def on_size(self, instance, value):
|
||
|
|
self.fbo.size = value
|
||
|
|
self.texture = self.fbo.texture
|
||
|
|
self.fbo_rect.size = value
|
||
|
|
|
||
|
|
def on_pos(self, instance, value):
|
||
|
|
self.fbo_rect.pos = value
|
||
|
|
|
||
|
|
def on_texture(self, instance, value):
|
||
|
|
self.fbo_rect.texture = value
|
||
|
|
|
||
|
|
|
||
|
|
if __name__ == '__main__':
|
||
|
|
from kivy.uix.button import Button
|
||
|
|
from kivy.app import App
|
||
|
|
|
||
|
|
class TestFboApp(App):
|
||
|
|
def build(self):
|
||
|
|
|
||
|
|
# test with FboFloatLayout or FloatLayout
|
||
|
|
# comment/uncomment to test it
|
||
|
|
root = FboFloatLayout()
|
||
|
|
# root = FloatLayout()
|
||
|
|
|
||
|
|
# this part of creation can be slow. try to optimize the loop a
|
||
|
|
# little bit.
|
||
|
|
s = 30
|
||
|
|
size = (s, s)
|
||
|
|
sh = (None, None)
|
||
|
|
add = root.add_widget
|
||
|
|
print('Creating 5000 widgets...')
|
||
|
|
for i in range(5000):
|
||
|
|
x = (i % 40) * s
|
||
|
|
y = int(i / 40) * s
|
||
|
|
add(Button(text=str(i), pos=(x, y), size_hint=sh, size=size))
|
||
|
|
if i % 1000 == 1000 - 1:
|
||
|
|
print(5000 - i - 1, 'left...')
|
||
|
|
|
||
|
|
return root
|
||
|
|
|
||
|
|
TestFboApp().run()
|