Blend modes decide how two colors will mix together. More...

Typedefs
using	SDL::BlendOperation = SDL_BlendOperation
	The blend operation used when combining source and destination pixel components.

using	SDL::BlendFactor = SDL_BlendFactor
	The normalized factor used to multiply pixel components.

Functions
BlendMode	SDL::ComposeCustomBlendMode (BlendFactor srcColorFactor, BlendFactor dstColorFactor, BlendOperation colorOperation, BlendFactor srcAlphaFactor, BlendFactor dstAlphaFactor, BlendOperation alphaOperation)
	Compose a custom blend mode for renderers.

Variables
constexpr BlendOperation	SDL::BLENDOPERATION_ADD = SDL_BLENDOPERATION_ADD
	dst + src: supported by all renderers

constexpr BlendOperation	SDL::BLENDOPERATION_SUBTRACT = SDL_BLENDOPERATION_SUBTRACT
	src - dst : supported by D3D, OpenGL, OpenGLES, and Vulkan

constexpr BlendOperation	SDL::BLENDOPERATION_REV_SUBTRACT
	dst - src : supported by D3D, OpenGL, OpenGLES, and Vulkan

constexpr BlendOperation	SDL::BLENDOPERATION_MINIMUM = SDL_BLENDOPERATION_MINIMUM
	min(dst, src) : supported by D3D, OpenGL, OpenGLES, and Vulkan

constexpr BlendOperation	SDL::BLENDOPERATION_MAXIMUM = SDL_BLENDOPERATION_MAXIMUM
	max(dst, src) : supported by D3D, OpenGL, OpenGLES, and Vulkan

constexpr BlendFactor	SDL::BLENDFACTOR_ZERO = SDL_BLENDFACTOR_ZERO
	0, 0, 0, 0

constexpr BlendFactor	SDL::BLENDFACTOR_ONE = SDL_BLENDFACTOR_ONE
	1, 1, 1, 1

constexpr BlendFactor	SDL::BLENDFACTOR_SRC_COLOR = SDL_BLENDFACTOR_SRC_COLOR
	srcR, srcG, srcB, srcA

constexpr BlendFactor	SDL::BLENDFACTOR_ONE_MINUS_SRC_COLOR
	1-srcR, 1-srcG, 1-srcB, 1-srcA

constexpr BlendFactor	SDL::BLENDFACTOR_SRC_ALPHA = SDL_BLENDFACTOR_SRC_ALPHA
	srcA, srcA, srcA, srcA

constexpr BlendFactor	SDL::BLENDFACTOR_ONE_MINUS_SRC_ALPHA
	1-srcA, 1-srcA, 1-srcA, 1-srcA

constexpr BlendFactor	SDL::BLENDFACTOR_DST_COLOR = SDL_BLENDFACTOR_DST_COLOR
	dstR, dstG, dstB, dstA

constexpr BlendFactor	SDL::BLENDFACTOR_ONE_MINUS_DST_COLOR
	1-dstR, 1-dstG, 1-dstB, 1-dstA

constexpr BlendFactor	SDL::BLENDFACTOR_DST_ALPHA = SDL_BLENDFACTOR_DST_ALPHA
	dstA, dstA, dstA, dstA

constexpr BlendFactor	SDL::BLENDFACTOR_ONE_MINUS_DST_ALPHA
	1-dstA, 1-dstA, 1-dstA, 1-dstA

BlendModes
using	SDL::BlendMode = Uint32
	A set of blend modes used in drawing operations.

constexpr BlendMode	SDL::BLENDMODE_NONE = SDL_BLENDMODE_NONE
	no blending: dstRGBA = srcRGBA

constexpr BlendMode	SDL::BLENDMODE_BLEND = SDL_BLENDMODE_BLEND
	alpha blending: dstRGB = (srcRGB * srcA) + (dstRGB * (1-srcA)), dstA = srcA + (dstA * (1-srcA))

constexpr BlendMode	SDL::BLENDMODE_BLEND_PREMULTIPLIED
	pre-multiplied alpha blending: dstRGBA = srcRGBA + (dstRGBA * (1-srcA))

constexpr BlendMode	SDL::BLENDMODE_ADD = SDL_BLENDMODE_ADD
	additive blending: dstRGB = (srcRGB * srcA) + dstRGB, dstA = dstA

constexpr BlendMode	SDL::BLENDMODE_ADD_PREMULTIPLIED
	pre-multiplied additive blending: dstRGB = srcRGB + dstRGB, dstA = dstA

constexpr BlendMode	SDL::BLENDMODE_MOD = SDL_BLENDMODE_MOD
	color modulate: dstRGB = srcRGB * dstRGB, dstA = dstA

constexpr BlendMode	SDL::BLENDMODE_MUL = SDL_BLENDMODE_MUL
	color multiply: dstRGB = (srcRGB * dstRGB) + (dstRGB * (1-srcA)), dstA = dstA

constexpr BlendMode	SDL::BLENDMODE_INVALID = SDL_BLENDMODE_INVALID
	INVALID.

Detailed Description

There are both standard modes for basic needs and a means to create custom modes, dictating what sort of math to do on what color components.

Typedef Documentation

◆ BlendFactor

using SDL::BlendFactor = typedef SDL_BlendFactor

The blend factors are multiplied with the pixels from a drawing operation (src) and the pixels from the render target (dst) before the blend operation. The comma-separated factors listed above are always applied in the component order red, green, blue, and alpha.

◆ BlendMode

using SDL::BlendMode = typedef Uint32

These predefined blend modes are supported everywhere.

Additional values may be obtained from ComposeCustomBlendMode().

Since: This datatype is available since SDL 3.2.0.

See also: ComposeCustomBlendMode

Function Documentation

◆ ComposeCustomBlendMode()

BlendMode SDL::ComposeCustomBlendMode	(	BlendFactor	srcColorFactor,
		BlendFactor	dstColorFactor,
		BlendOperation	colorOperation,
		BlendFactor	srcAlphaFactor,
		BlendFactor	dstAlphaFactor,
		BlendOperation	alphaOperation
	)

inline

The functions SDL_SetRenderDrawBlendMode and SDL_SetTextureBlendMode accept the SDL_BlendMode returned by this function if the renderer supports it.

A blend mode controls how the pixels from a drawing operation (source) get combined with the pixels from the render target (destination). First, the components of the source and destination pixels get multiplied with their blend factors. Then, the blend operation takes the two products and calculates the result that will get stored in the render target.

Expressed in pseudocode, it would look like this:

dstRGB = colorOperation(srcRGB * srcColorFactor, dstRGB * dstColorFactor);

dstA = alphaOperation(srcA * srcAlphaFactor, dstA * dstAlphaFactor);

Where the functions colorOperation(src, dst) and alphaOperation(src, dst) can return one of the following:

src + dst
src - dst
dst - src
min(src, dst)
max(src, dst)

The red, green, and blue components are always multiplied with the first, second, and third components of the SDL_BlendFactor, respectively. The fourth component is not used.

The alpha component is always multiplied with the fourth component of the SDL_BlendFactor. The other components are not used in the alpha calculation.

Support for these blend modes varies for each renderer. To check if a specific SDL_BlendMode is supported, create a renderer and pass it to either SDL_SetRenderDrawBlendMode or SDL_SetTextureBlendMode. They will return with an error if the blend mode is not supported.

This list describes the support of custom blend modes for each renderer. All renderers support the four blend modes listed in the SDL_BlendMode enumeration.

direct3d: Supports all operations with all factors. However, some factors produce unexpected results with SDL_BLENDOPERATION_MINIMUM and SDL_BLENDOPERATION_MAXIMUM.
direct3d11: Same as Direct3D 9.
opengl: Supports the SDL_BLENDOPERATION_ADD operation with all factors. OpenGL versions 1.1, 1.2, and 1.3 do not work correctly here.
opengles2: Supports the SDL_BLENDOPERATION_ADD, SDL_BLENDOPERATION_SUBTRACT, SDL_BLENDOPERATION_REV_SUBTRACT operations with all factors.
psp: No custom blend mode support.
software: No custom blend mode support.

Some renderers do not provide an alpha component for the default render target. The SDL_BLENDFACTOR_DST_ALPHA and SDL_BLENDFACTOR_ONE_MINUS_DST_ALPHA factors do not have an effect in this case.

Parameters

srcColorFactor	the SDL_BlendFactor applied to the red, green, and blue components of the source pixels.
dstColorFactor	the SDL_BlendFactor applied to the red, green, and blue components of the destination pixels.
colorOperation	the SDL_BlendOperation used to combine the red, green, and blue components of the source and destination pixels.
srcAlphaFactor	the SDL_BlendFactor applied to the alpha component of the source pixels.
dstAlphaFactor	the SDL_BlendFactor applied to the alpha component of the destination pixels.
alphaOperation	the SDL_BlendOperation used to combine the alpha component of the source and destination pixels.

Returns: an SDL_BlendMode that represents the chosen factors and operations.

Thread safety:: It is safe to call this function from any thread.

SDL_BLENDOPERATION_REV_SUBTRACT

Typedefs

Functions

Variables

BlendModes

Detailed Description

Typedef Documentation

◆ BlendFactor

◆ BlendMode

Function Documentation

◆ ComposeCustomBlendMode()

Variable Documentation

◆ BLENDFACTOR_ONE_MINUS_DST_ALPHA

◆ BLENDFACTOR_ONE_MINUS_DST_COLOR

◆ BLENDFACTOR_ONE_MINUS_SRC_ALPHA

◆ BLENDFACTOR_ONE_MINUS_SRC_COLOR

◆ BLENDMODE_ADD_PREMULTIPLIED

◆ BLENDMODE_BLEND_PREMULTIPLIED

◆ BLENDOPERATION_REV_SUBTRACT