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Framebuffer

Fbo is like an offscreen window. You can activate the fbo for rendering into a texture, and use your fbo as a texture for another drawing.

Fbo act as a kivy.graphics.instructions.Canvas.

Exemple of using an fbo for some color rectangles

from kivy.graphics import Fbo, Color, Rectangle

class FboTest(Widget):
    def __init__(self, **kwargs):
        super(FboTest, self).__init__(**kwargs)

        # first step is to create the fbo and use the fbo texture on other
        # rectangle

        with self.canvas:
            # create the fbo
            self.fbo = Fbo(size=(256, 256))

            # show our fbo on the widget in different size
            Color(1, 1, 1)
            Rectangle(size=(32, 32), texture=self.fbo.texture)
            Rectangle(pos=(32, 0), size=(64, 64), texture=self.fbo.texture)
            Rectangle(pos=(96, 0), size=(128, 128), texture=self.fbo.texture)

        # in the second step, you can draw whatever you want on the fbo
        with self.fbo:
            Color(1, 0, 0, .8)
            Rectangle(size=(256, 64))
            Color(0, 1, 0, .8)
            Rectangle(size=(64, 256))

If you change anything in the self.fbo object, it will be automaticly updated, and canvas where the fbo is putted will be automaticly updated too.

class kivy.graphics.fbo.Fbo(*args, **kwargs)

Bases: kivy.graphics.instructions.RenderContext

Fbo class for wrapping the OpenGL Framebuffer extension. The Fbo support “with” statement.

Parameters :
clear_color: tuple, default to (0, 0, 0, 0)

Define the default color for clearing the framebuffer

size: tuple, default to (1024, 1024)

Default size of the framebuffer

push_viewport: bool, default to True

If True, the OpenGL viewport will be set to the framebuffer size, and will be automatically restored when the framebuffer released.

with_depthbuffer: bool, default to True

If True, the framebuffer will be allocated with a Z buffer.

texture: Texture, default to None

If None, a default texture will be created.

bind()
Bind the FBO to the current opengl context.

Bind mean that you enable the Framebuffer, and all the drawing operations will act inside the Framebuffer, until release() is called.

The bind/release operation are automatically done when you add graphics object in it. But if you want to manipulate a Framebuffer yourself, you can use it like this:

self.fbo = FBO()
self.fbo.bind()
# do any drawing command
self.fbo.unbind()

# then, your fbo texture is available at
print self.fbo.texture
clear_buffer()

Clear the framebuffer with the clear_color

clear_color

Clear color in (red, green, blue, alpha) format.

release()

Release the Framebuffer (unbind).

size

Size of the framebuffer, in (width, height) format.

If you change the size, the framebuffer content will be lost.

texture

Return the framebuffer texture

class kivy.graphics.fbo.FboException

Bases: exceptions.Exception

FboException is fired when an FBO error happen during creation or usage.

resolve_status()

FboException.resolve_status(self, status)