201 lines
8.9 KiB
C
201 lines
8.9 KiB
C
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/*
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Simple DirectMedia Layer
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Copyright (C) 1997-2022 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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* \file SDL_blendmode.h
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*
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* Header file declaring the SDL_BlendMode enumeration
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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 "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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* \brief The blend mode used in SDL_RenderCopy() and drawing operations.
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*/
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typedef enum
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{
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SDL_BLENDMODE_NONE = 0x00000000, /**< no blending
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dstRGBA = srcRGBA */
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SDL_BLENDMODE_BLEND = 0x00000001, /**< alpha blending
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dstRGB = (srcRGB * srcA) + (dstRGB * (1-srcA))
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dstA = srcA + (dstA * (1-srcA)) */
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SDL_BLENDMODE_ADD = 0x00000002, /**< additive blending
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dstRGB = (srcRGB * srcA) + dstRGB
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dstA = dstA */
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SDL_BLENDMODE_MOD = 0x00000004, /**< color modulate
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dstRGB = srcRGB * dstRGB
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dstA = dstA */
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SDL_BLENDMODE_MUL = 0x00000008, /**< color multiply
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dstRGB = (srcRGB * dstRGB) + (dstRGB * (1-srcA))
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dstA = (srcA * dstA) + (dstA * (1-srcA)) */
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SDL_BLENDMODE_INVALID = 0x7FFFFFFF
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/* Additional custom blend modes can be returned by SDL_ComposeCustomBlendMode() */
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} SDL_BlendMode;
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/**
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* \brief The blend operation used when combining source and destination pixel components
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*/
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typedef enum
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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, /**< dst - src : supported by D3D9, D3D11, OpenGL, OpenGLES */
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SDL_BLENDOPERATION_REV_SUBTRACT = 0x3, /**< src - dst : supported by D3D9, D3D11, OpenGL, OpenGLES */
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SDL_BLENDOPERATION_MINIMUM = 0x4, /**< min(dst, src) : supported by D3D11 */
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SDL_BLENDOPERATION_MAXIMUM = 0x5 /**< max(dst, src) : supported by D3D11 */
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} SDL_BlendOperation;
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/**
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* \brief The normalized factor used to multiply pixel components
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*/
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typedef enum
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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 in
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* SDL 2.0.6. All renderers support the four blend modes listed in the
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* SDL_BlendMode enumeration.
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*
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* - **direct3d**: Supports `SDL_BLENDOPERATION_ADD` with all factors.
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* - **direct3d11**: 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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* - **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 with SDL
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* 2.0.6.
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* - **opengles**: Supports the `SDL_BLENDOPERATION_ADD` operation with all
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* factors. Color and alpha factors need to be the same. OpenGL ES 1
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* implementation specific: May also support `SDL_BLENDOPERATION_SUBTRACT`
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* and `SDL_BLENDOPERATION_REV_SUBTRACT`. May support color and alpha
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* operations being different from each other. May support color and alpha
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* factors being different from each other.
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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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* \since This function is available since SDL 2.0.6.
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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 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 "close_code.h"
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#endif /* SDL_blendmode_h_ */
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/* vi: set ts=4 sw=4 expandtab: */
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