NAME

       SDL_ComposeCustomBlendMode - Compose a custom blend mode for renderers.

HEADER FILE

       Defined in SDL3/SDL_blendmode.h

SYNOPSIS

       #include "SDL3/SDL.h"

       SDL_BlendMode SDL_ComposeCustomBlendMode(SDL_BlendFactor srcColorFactor,
                                            SDL_BlendFactor dstColorFactor,
                                            SDL_BlendOperation colorOperation,
                                            SDL_BlendFactor srcAlphaFactor,
                                            SDL_BlendFactor dstAlphaFactor,
                                            SDL_BlendOperation alphaOperation);

DESCRIPTION

       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.

FUNCTION 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.

RETURN VALUE

       ( SDL_BlendMode ) Returns an SDL_BlendMode

       that represents the chosen factors and operations.

THREAD SAFETY

       It is safe to call this function from any thread.

AVAILABILITY

       This function is available since SDL 3.2.0.

SEE ALSO

       •(3),       SDL_SetRenderDrawBlendMode(3),       •(3),        SDL_GetRenderDrawBlendMode(3),        •(3),
       SDL_SetTextureBlendMode(3), •(3), SDL_GetTextureBlendMode(3)

Simple Directmedia Layer                            SDL 3.2.8                      SDL_ComposeCustomBlendMode(3)