VkBlendFactor(3)

# VkBlendFactor(3) Manual Page

## Name

VkBlendFactor - Framebuffer blending factors

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## C Specification

The source and destination color and alpha blending factors are selected from the enum:

    // Provided by VK_VERSION_1_0
    typedef enum VkBlendFactor {
        VK_BLEND_FACTOR_ZERO = 0,
        VK_BLEND_FACTOR_ONE = 1,
        VK_BLEND_FACTOR_SRC_COLOR = 2,
        VK_BLEND_FACTOR_ONE_MINUS_SRC_COLOR = 3,
        VK_BLEND_FACTOR_DST_COLOR = 4,
        VK_BLEND_FACTOR_ONE_MINUS_DST_COLOR = 5,
        VK_BLEND_FACTOR_SRC_ALPHA = 6,
        VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA = 7,
        VK_BLEND_FACTOR_DST_ALPHA = 8,
        VK_BLEND_FACTOR_ONE_MINUS_DST_ALPHA = 9,
        VK_BLEND_FACTOR_CONSTANT_COLOR = 10,
        VK_BLEND_FACTOR_ONE_MINUS_CONSTANT_COLOR = 11,
        VK_BLEND_FACTOR_CONSTANT_ALPHA = 12,
        VK_BLEND_FACTOR_ONE_MINUS_CONSTANT_ALPHA = 13,
        VK_BLEND_FACTOR_SRC_ALPHA_SATURATE = 14,
        VK_BLEND_FACTOR_SRC1_COLOR = 15,
        VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR = 16,
        VK_BLEND_FACTOR_SRC1_ALPHA = 17,
        VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA = 18,
    } VkBlendFactor;

## Description

The semantics of the enum values are described in the table below:

Table 1. Blend Factors
VkBlendFactor | RGB Blend Factors (Sr,Sg,Sb) or (Dr,Dg,Db) | Alpha Blend Factor (Sa or Da)
--- | --- | ---
`VK_BLEND_FACTOR_ZERO` | (0,0,0) | 0
`VK_BLEND_FACTOR_ONE` | (1,1,1) | 1
`VK_BLEND_FACTOR_SRC_COLOR` | (Rs0,Gs0,Bs0) | As0
`VK_BLEND_FACTOR_ONE_MINUS_SRC_COLOR` | (1-Rs0,1-Gs0,1-Bs0) | 1-As0
`VK_BLEND_FACTOR_DST_COLOR` | (Rd,Gd,Bd) | Ad
`VK_BLEND_FACTOR_ONE_MINUS_DST_COLOR` | (1-Rd,1-Gd,1-Bd) | 1-Ad
`VK_BLEND_FACTOR_SRC_ALPHA` | (As0,As0,As0) | As0
`VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA` | (1-As0,1-As0,1-As0) | 1-As0
`VK_BLEND_FACTOR_DST_ALPHA` | (Ad,Ad,Ad) | Ad
`VK_BLEND_FACTOR_ONE_MINUS_DST_ALPHA` | (1-Ad,1-Ad,1-Ad) | 1-Ad
`VK_BLEND_FACTOR_CONSTANT_COLOR` | (Rc,Gc,Bc) | Ac
`VK_BLEND_FACTOR_ONE_MINUS_CONSTANT_COLOR` | (1-Rc,1-Gc,1-Bc) | 1-Ac
`VK_BLEND_FACTOR_CONSTANT_ALPHA` | (Ac,Ac,Ac) | Ac
`VK_BLEND_FACTOR_ONE_MINUS_CONSTANT_ALPHA` | (1-Ac,1-Ac,1-Ac) | 1-Ac
`VK_BLEND_FACTOR_SRC_ALPHA_SATURATE` | (f,f,f); f = min(As0,1-Ad) | 1
`VK_BLEND_FACTOR_SRC1_COLOR` | (Rs1,Gs1,Bs1) | As1
`VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR` | (1-Rs1,1-Gs1,1-Bs1) | 1-As1
`VK_BLEND_FACTOR_SRC1_ALPHA` | (As1,As1,As1) | As1
`VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA` | (1-As1,1-As1,1-As1) | 1-As1

In this table, the following conventions are used:

- Rs0,Gs0,Bs0 and As0 represent the first source color R, G, B, and A components, respectively, for the fragment output location corresponding to the color attachment being blended.

- Rs1,Gs1,Bs1 and As1 represent the second source color R, G, B, and A components, respectively, used in dual source blending modes, for the fragment output location corresponding to the color attachment being blended.

- Rd,Gd,Bd and Ad represent the R, G, B, and A components of the destination color. That is, the color currently in the corresponding color attachment for this fragment/sample.

- Rc,Gc,Bc and Ac represent the blend constant R, G, B, and A components, respectively.

## See Also

VK_VERSION_1_0, VkColorBlendEquationEXT, VkPipelineColorBlendAttachmentState

## Document Notes

For more information, see the Vulkan Specification

This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.

## Copyright

Copyright 2014-2024 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0