Vocabulary
gpu.state

Class description
A blend-mode is specified as part of the blend-state to determine the blending equation used between the source (incoming fragment) and destination (existing framebuffer value) colors of blended pixels.

•	The equation slot determines how the source and destination colors are combined after the source-function and dest-function have been applied. • eq-add indicates that the source and destination results are added. • eq-subtract indicates that the destination result is subtracted from the source. • eq-reverse-subtract indicates that the source result is subtracted from the destination. • eq-min indicates that the componentwise minimum of the source and destination results is taken. • eq-max indicates that the componentwise maximum of the source and destination results is taken.
•	The source-function and dest-function slots each specify a function to apply to the source, destination, or constant color values to generate a blending factor that is multiplied respectively against the source or destination value before feeding the results to the equation.
•	• func-zero returns a constant factor of zero. • func-one returns a constant factor of one. • func-source returns the corresponding source color component for every result component. • func-one-minus-source returns one minus the corresponding source color component for every result component. • func-dest returns the corresponding destination color component for every result component. • func-one-minus-dest returns one minus the corresponding destination color component for every result component. • func-constant returns the corresponding component of the current blend-state's constant-color for every result component. • func-one-minus-constant returns one minus the corresponding component of the current blend-state's constant-color for every result component. • func-source-alpha returns the source alpha component for every result component. • func-one-minus-source-alpha returns one minus the source alpha component for every result component. • func-dest-alpha returns the destination alpha component for every result component. • func-one-minus-dest-alpha returns one minus the destination alpha component for every result component. • func-constant-alpha returns the alpha component of the current blend-state's constant-color for every result component. • func-one-minus-constant-alpha returns one minus the alpha component of the current blend-state's constant-color for every result component.
•	A typical transparency effect will use the values:
•	T{ blend-mode { equation eq-add } { source-function func-source-alpha } { dest-function func-one-minus-source-alpha } }

See also
<blend-mode>

Definition

IN: gpu.state

TUPLE: blend-mode
{ equation blend-equation read-only initial: eq-add } {
source-function source-blend-function read-only initial:
func-source-alpha
} {
dest-function blend-function read-only initial:
func-one-minus-source-alpha
} ;