Framebuffer#

class moderngl.Framebuffer#

A Framebuffer is a collection of buffers that can be used as the destination for rendering.

The buffers for Framebuffer objects reference images from either Textures or Renderbuffers. Create a Framebuffer using Context.framebuffer().

Create#

Context.simple_framebuffer(size: Tuple[int, int], components: int = 4, *, samples: int = 0, dtype: str = 'f1') → moderngl.framebuffer.Framebuffer

Creates a Framebuffer with a single color attachment and depth buffer using moderngl.Renderbuffer attachments.

Parameters

  • size (tuple) – The width and height of the renderbuffer.

  • components (int) – The number of components 1, 2, 3 or 4.

Keyword Arguments

  • samples (int) – The number of samples. Value 0 means no multisample format.

  • dtype (str) – Data type.

Returns

Framebuffer object

Context.framebuffer(color_attachments: Any = (), depth_attachment: Optional[Union[moderngl.texture.Texture, moderngl.renderbuffer.Renderbuffer]] = None) → moderngl.framebuffer.Framebuffer

A Framebuffer is a collection of buffers that can be used as the destination for rendering. The buffers for Framebuffer objects reference images from either Textures or Renderbuffers.

Parameters
Returns

Framebuffer object

Methods#

Framebuffer.clear(red: float = 0.0, green: float = 0.0, blue: float = 0.0, alpha: float = 0.0, depth: float = 1.0, *, viewport: Optional[Union[Tuple[int, int], Tuple[int, int, int, int]]] = None, color: Optional[Tuple[float, float, float, float]] = None) → None#

Clear the framebuffer.

If a viewport passed in, a scissor test will be used to clear the given viewport. This viewport take presence over the framebuffers scissor. Clearing can still be done with scissor if no viewport is passed in.

This method also respects the color_mask and depth_mask. It can for example be used to only clear the depth or color buffer or specific components in the color buffer.

If the viewport is a 2-tuple it will clear the (0, 0, width, height) where (width, height) is the 2-tuple.

If the viewport is a 4-tuple it will clear the given viewport.

Parameters

  • red (float) – color component.

  • green (float) – color component.

  • blue (float) – color component.

  • alpha (float) – alpha component.

  • depth (float) – depth value.

Keyword Arguments

  • viewport (tuple) – The viewport.

  • color (tuple) – Optional tuple replacing the red, green, blue and alpha arguments

Framebuffer.read(viewport: Optional[Union[Tuple[int, int], Tuple[int, int, int, int]]] = None, components: int = 3, *, attachment: int = 0, alignment: int = 1, dtype: str = 'f1', clamp: bool = False) → bytes#

Read the content of the framebuffer.

# Read the first color attachment's RGBA data
data = fbo.read(components=4)
# Read the second color attachment's RGB data
data = fbo.read(attachment=1)
# Read the depth attachment
data = fbo.read(attachment=-1)
# Read the lower left 10 x 10 pixels from the first color attachment
data = fbo.read(viewport=(0, 0, 10, 10))
Parameters

  • viewport (tuple) – The viewport.

  • components (int) – The number of components to read.

Keyword Arguments

  • attachment (int) – The color attachment number. -1 for the depth attachment

  • alignment (int) – The byte alignment of the pixels.

  • dtype (str) – Data type.

  • clamp (bool) – Clamps floating point values to [0.0, 1.0]

Returns

bytes

Framebuffer.read_into(buffer: Any, viewport: Optional[Union[Tuple[int, int], Tuple[int, int, int, int]]] = None, components: int = 3, *, attachment: int = 0, alignment: int = 1, dtype: str = 'f1', write_offset: int = 0) → None#

Read the content of the framebuffer into a buffer.

Parameters

  • buffer (bytearray) – The buffer that will receive the pixels.

  • viewport (tuple) – The viewport.

  • components (int) – The number of components to read.

Keyword Arguments

  • attachment (int) – The color attachment.

  • alignment (int) – The byte alignment of the pixels.

  • dtype (str) – Data type.

  • write_offset (int) – The write offset.

Framebuffer.use() → None#

Bind the framebuffer. Sets the target for rendering commands.

Framebuffer.release() → None#

Release the ModernGL object.

Attributes#

Framebuffer.viewport#

Get or set the viewport of the framebuffer.

Type

tuple

Framebuffer.scissor#

Get or set the scissor box of the framebuffer.

When scissor testing is enabled fragments outside the defined scissor box will be discarded. This applies to rendered geometry or Framebuffer.clear().

Setting is value enables scissor testing in the framebuffer. Setting the scissor to None disables scissor testing and reverts the scissor box to match the framebuffer size.

Example:

# Enable scissor testing
>>> ctx.scissor = 100, 100, 200, 100
# Disable scissor testing
>>> ctx.scissor = None
Type

tuple

Framebuffer.color_mask#

The color mask of the framebuffer.

Color masking controls what components in color attachments will be affected by fragment write operations. This includes rendering geometry and clearing the framebuffer.

Default value: (True, True, True, True).

Examples:

# Block writing to all color components (rgba) in color attachments
fbo.color_mask = False, False, False, False

# Re-enable writing to color attachments
fbo.color_mask = True, True, True, True

# Block fragment writes to alpha channel
fbo.color_mask = True, True, True, False
Type

tuple

Framebuffer.depth_mask#

The depth mask of the framebuffer.

Depth mask enables or disables write operations to the depth buffer. This also applies when clearing the framebuffer. If depth testing is enabled fragments will still be culled, but the depth buffer will not be updated with new values. This is a very useful tool in many rendering techniques.

Default value: True

Type

bool

Framebuffer.width#

The width of the framebuffer.

Framebuffers created by a window will only report its initial size. It’s better get size information from the window itself.

Type

int

Framebuffer.height#

The height of the framebuffer.

Framebuffers created by a window will only report its initial size. It’s better get size information from the window itself.

Type

int

Framebuffer.size#

The size of the framebuffer.

Framebuffers created by a window will only report its initial size. It’s better get size information from the window itself.

Type

tuple

Framebuffer.samples#

The samples of the framebuffer.

Type

int

Framebuffer.bits#

The bits of the framebuffer.

Type

dict

Framebuffer.color_attachments#

The color attachments of the framebuffer.

Type

tuple

Framebuffer.depth_attachment#

The depth attachment of the framebuffer.

Type

Texture or Renderbuffer

Framebuffer.glo#

The internal OpenGL object.

This values is provided for debug purposes only.

Type

int

Framebuffer.mglo#

Internal representation for debug purposes only.

Framebuffer.extra: Any#

Attribute for storing user defined objects

Framebuffer.ctx: Context#

The context this object belongs to