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203 lines
9.1 KiB
C
203 lines
9.1 KiB
C
/*
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Simple DirectMedia Layer
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Copyright (C) 1997-2024 Sam Lantinga <slouken@libsdl.org>
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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/**
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* # CategoryBlendmode
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*
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* Blend modes decide how two colors will mix together. There are both
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* standard modes for basic needs and a means to create custom modes,
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* dictating what sort of math to do on what color components.
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*/
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#ifndef SDL_blendmode_h_
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#define SDL_blendmode_h_
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#include <SDL3/SDL_stdinc.h>
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#include <SDL3/SDL_begin_code.h>
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/* Set up for C function definitions, even when using C++ */
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* A set of blend modes used in drawing operations.
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*
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* These predefined blend modes are supported everywhere.
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*
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* Additional values may be obtained from SDL_ComposeCustomBlendMode.
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*
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* \since This datatype is available since SDL 3.1.3.
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*
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* \sa SDL_ComposeCustomBlendMode
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*/
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typedef Uint32 SDL_BlendMode;
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#define SDL_BLENDMODE_NONE 0x00000000u /**< no blending: dstRGBA = srcRGBA */
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#define SDL_BLENDMODE_BLEND 0x00000001u /**< alpha blending: dstRGB = (srcRGB * srcA) + (dstRGB * (1-srcA)), dstA = srcA + (dstA * (1-srcA)) */
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#define SDL_BLENDMODE_BLEND_PREMULTIPLIED 0x00000010u /**< pre-multiplied alpha blending: dstRGBA = srcRGBA + (dstRGBA * (1-srcA)) */
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#define SDL_BLENDMODE_ADD 0x00000002u /**< additive blending: dstRGB = (srcRGB * srcA) + dstRGB, dstA = dstA */
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#define SDL_BLENDMODE_ADD_PREMULTIPLIED 0x00000020u /**< pre-multiplied additive blending: dstRGB = srcRGB + dstRGB, dstA = dstA */
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#define SDL_BLENDMODE_MOD 0x00000004u /**< color modulate: dstRGB = srcRGB * dstRGB, dstA = dstA */
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#define SDL_BLENDMODE_MUL 0x00000008u /**< color multiply: dstRGB = (srcRGB * dstRGB) + (dstRGB * (1-srcA)), dstA = dstA */
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#define SDL_BLENDMODE_INVALID 0x7FFFFFFFu
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/**
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* The blend operation used when combining source and destination pixel
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* components.
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*
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* \since This enum is available since SDL 3.1.3.
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*/
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typedef enum SDL_BlendOperation
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{
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SDL_BLENDOPERATION_ADD = 0x1, /**< dst + src: supported by all renderers */
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SDL_BLENDOPERATION_SUBTRACT = 0x2, /**< src - dst : supported by D3D, OpenGL, OpenGLES, and Vulkan */
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SDL_BLENDOPERATION_REV_SUBTRACT = 0x3, /**< dst - src : supported by D3D, OpenGL, OpenGLES, and Vulkan */
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SDL_BLENDOPERATION_MINIMUM = 0x4, /**< min(dst, src) : supported by D3D, OpenGL, OpenGLES, and Vulkan */
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SDL_BLENDOPERATION_MAXIMUM = 0x5 /**< max(dst, src) : supported by D3D, OpenGL, OpenGLES, and Vulkan */
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} SDL_BlendOperation;
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/**
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* The normalized factor used to multiply pixel components.
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*
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* The blend factors are multiplied with the pixels from a drawing operation
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* (src) and the pixels from the render target (dst) before the blend
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* operation. The comma-separated factors listed above are always applied in
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* the component order red, green, blue, and alpha.
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*
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* \since This enum is available since SDL 3.1.3.
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*/
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typedef enum SDL_BlendFactor
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{
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SDL_BLENDFACTOR_ZERO = 0x1, /**< 0, 0, 0, 0 */
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SDL_BLENDFACTOR_ONE = 0x2, /**< 1, 1, 1, 1 */
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SDL_BLENDFACTOR_SRC_COLOR = 0x3, /**< srcR, srcG, srcB, srcA */
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SDL_BLENDFACTOR_ONE_MINUS_SRC_COLOR = 0x4, /**< 1-srcR, 1-srcG, 1-srcB, 1-srcA */
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SDL_BLENDFACTOR_SRC_ALPHA = 0x5, /**< srcA, srcA, srcA, srcA */
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SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA = 0x6, /**< 1-srcA, 1-srcA, 1-srcA, 1-srcA */
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SDL_BLENDFACTOR_DST_COLOR = 0x7, /**< dstR, dstG, dstB, dstA */
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SDL_BLENDFACTOR_ONE_MINUS_DST_COLOR = 0x8, /**< 1-dstR, 1-dstG, 1-dstB, 1-dstA */
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SDL_BLENDFACTOR_DST_ALPHA = 0x9, /**< dstA, dstA, dstA, dstA */
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SDL_BLENDFACTOR_ONE_MINUS_DST_ALPHA = 0xA /**< 1-dstA, 1-dstA, 1-dstA, 1-dstA */
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} SDL_BlendFactor;
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/**
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* Compose a custom blend mode for renderers.
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*
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* The functions SDL_SetRenderDrawBlendMode and SDL_SetTextureBlendMode accept
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* the SDL_BlendMode returned by this function if the renderer supports it.
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*
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* A blend mode controls how the pixels from a drawing operation (source) get
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* combined with the pixels from the render target (destination). First, the
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* components of the source and destination pixels get multiplied with their
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* blend factors. Then, the blend operation takes the two products and
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* calculates the result that will get stored in the render target.
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*
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* Expressed in pseudocode, it would look like this:
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*
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* ```c
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* dstRGB = colorOperation(srcRGB * srcColorFactor, dstRGB * dstColorFactor);
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* dstA = alphaOperation(srcA * srcAlphaFactor, dstA * dstAlphaFactor);
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* ```
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*
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* Where the functions `colorOperation(src, dst)` and `alphaOperation(src,
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* dst)` can return one of the following:
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*
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* - `src + dst`
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* - `src - dst`
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* - `dst - src`
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* - `min(src, dst)`
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* - `max(src, dst)`
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*
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* The red, green, and blue components are always multiplied with the first,
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* second, and third components of the SDL_BlendFactor, respectively. The
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* fourth component is not used.
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*
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* The alpha component is always multiplied with the fourth component of the
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* SDL_BlendFactor. The other components are not used in the alpha
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* calculation.
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*
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* Support for these blend modes varies for each renderer. To check if a
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* specific SDL_BlendMode is supported, create a renderer and pass it to
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* either SDL_SetRenderDrawBlendMode or SDL_SetTextureBlendMode. They will
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* return with an error if the blend mode is not supported.
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*
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* This list describes the support of custom blend modes for each renderer.
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* All renderers support the four blend modes listed in the SDL_BlendMode
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* enumeration.
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*
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* - **direct3d**: Supports all operations with all factors. However, some
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* factors produce unexpected results with `SDL_BLENDOPERATION_MINIMUM` and
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* `SDL_BLENDOPERATION_MAXIMUM`.
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* - **direct3d11**: Same as Direct3D 9.
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* - **opengl**: Supports the `SDL_BLENDOPERATION_ADD` operation with all
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* factors. OpenGL versions 1.1, 1.2, and 1.3 do not work correctly here.
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* - **opengles2**: Supports the `SDL_BLENDOPERATION_ADD`,
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* `SDL_BLENDOPERATION_SUBTRACT`, `SDL_BLENDOPERATION_REV_SUBTRACT`
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* operations with all factors.
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* - **psp**: No custom blend mode support.
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* - **software**: No custom blend mode support.
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*
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* Some renderers do not provide an alpha component for the default render
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* target. The `SDL_BLENDFACTOR_DST_ALPHA` and
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* `SDL_BLENDFACTOR_ONE_MINUS_DST_ALPHA` factors do not have an effect in this
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* case.
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*
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* \param srcColorFactor the SDL_BlendFactor applied to the red, green, and
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* blue components of the source pixels.
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* \param dstColorFactor the SDL_BlendFactor applied to the red, green, and
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* blue components of the destination pixels.
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* \param colorOperation the SDL_BlendOperation used to combine the red,
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* green, and blue components of the source and
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* destination pixels.
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* \param srcAlphaFactor the SDL_BlendFactor applied to the alpha component of
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* the source pixels.
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* \param dstAlphaFactor the SDL_BlendFactor applied to the alpha component of
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* the destination pixels.
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* \param alphaOperation the SDL_BlendOperation used to combine the alpha
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* component of the source and destination pixels.
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* \returns an SDL_BlendMode that represents the chosen factors and
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* operations.
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*
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* \threadsafety It is safe to call this function from any thread.
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*
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* \since This function is available since SDL 3.1.3.
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*
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* \sa SDL_SetRenderDrawBlendMode
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* \sa SDL_GetRenderDrawBlendMode
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* \sa SDL_SetTextureBlendMode
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* \sa SDL_GetTextureBlendMode
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*/
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extern SDL_DECLSPEC SDL_BlendMode SDLCALL SDL_ComposeCustomBlendMode(SDL_BlendFactor srcColorFactor,
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SDL_BlendFactor dstColorFactor,
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SDL_BlendOperation colorOperation,
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SDL_BlendFactor srcAlphaFactor,
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SDL_BlendFactor dstAlphaFactor,
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SDL_BlendOperation alphaOperation);
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/* Ends C function definitions when using C++ */
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#ifdef __cplusplus
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}
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#endif
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#include <SDL3/SDL_close_code.h>
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#endif /* SDL_blendmode_h_ */
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