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- /*
- Simple DirectMedia Layer
- Copyright (C) 1997-2022 Sam Lantinga <slouken@libsdl.org>
-
- This software is provided 'as-is', without any express or implied
- warranty. In no event will the authors be held liable for any damages
- arising from the use of this software.
-
- Permission is granted to anyone to use this software for any purpose,
- including commercial applications, and to alter it and redistribute it
- freely, subject to the following restrictions:
-
- 1. The origin of this software must not be misrepresented; you must not
- claim that you wrote the original software. If you use this software
- in a product, an acknowledgment in the product documentation would be
- appreciated but is not required.
- 2. Altered source versions must be plainly marked as such, and must not be
- misrepresented as being the original software.
- 3. This notice may not be removed or altered from any source distribution.
- */
-
- /**
- * \file SDL_blendmode.h
- *
- * Header file declaring the SDL_BlendMode enumeration
- */
-
- #ifndef SDL_blendmode_h_
- #define SDL_blendmode_h_
-
- #include "begin_code.h"
- /* Set up for C function definitions, even when using C++ */
- #ifdef __cplusplus
- extern "C" {
- #endif
-
- /**
- * \brief The blend mode used in SDL_RenderCopy() and drawing operations.
- */
- typedef enum
- {
- SDL_BLENDMODE_NONE = 0x00000000, /**< no blending
- dstRGBA = srcRGBA */
- SDL_BLENDMODE_BLEND = 0x00000001, /**< alpha blending
- dstRGB = (srcRGB * srcA) + (dstRGB * (1-srcA))
- dstA = srcA + (dstA * (1-srcA)) */
- SDL_BLENDMODE_ADD = 0x00000002, /**< additive blending
- dstRGB = (srcRGB * srcA) + dstRGB
- dstA = dstA */
- SDL_BLENDMODE_MOD = 0x00000004, /**< color modulate
- dstRGB = srcRGB * dstRGB
- dstA = dstA */
- SDL_BLENDMODE_MUL = 0x00000008, /**< color multiply
- dstRGB = (srcRGB * dstRGB) + (dstRGB * (1-srcA))
- dstA = (srcA * dstA) + (dstA * (1-srcA)) */
- SDL_BLENDMODE_INVALID = 0x7FFFFFFF
-
- /* Additional custom blend modes can be returned by SDL_ComposeCustomBlendMode() */
-
- } SDL_BlendMode;
-
- /**
- * \brief The blend operation used when combining source and destination pixel components
- */
- typedef enum
- {
- SDL_BLENDOPERATION_ADD = 0x1, /**< dst + src: supported by all renderers */
- SDL_BLENDOPERATION_SUBTRACT = 0x2, /**< dst - src : supported by D3D9, D3D11, OpenGL, OpenGLES */
- SDL_BLENDOPERATION_REV_SUBTRACT = 0x3, /**< src - dst : supported by D3D9, D3D11, OpenGL, OpenGLES */
- SDL_BLENDOPERATION_MINIMUM = 0x4, /**< min(dst, src) : supported by D3D9, D3D11 */
- SDL_BLENDOPERATION_MAXIMUM = 0x5 /**< max(dst, src) : supported by D3D9, D3D11 */
- } SDL_BlendOperation;
-
- /**
- * \brief The normalized factor used to multiply pixel components
- */
- typedef enum
- {
- SDL_BLENDFACTOR_ZERO = 0x1, /**< 0, 0, 0, 0 */
- SDL_BLENDFACTOR_ONE = 0x2, /**< 1, 1, 1, 1 */
- SDL_BLENDFACTOR_SRC_COLOR = 0x3, /**< srcR, srcG, srcB, srcA */
- SDL_BLENDFACTOR_ONE_MINUS_SRC_COLOR = 0x4, /**< 1-srcR, 1-srcG, 1-srcB, 1-srcA */
- SDL_BLENDFACTOR_SRC_ALPHA = 0x5, /**< srcA, srcA, srcA, srcA */
- SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA = 0x6, /**< 1-srcA, 1-srcA, 1-srcA, 1-srcA */
- SDL_BLENDFACTOR_DST_COLOR = 0x7, /**< dstR, dstG, dstB, dstA */
- SDL_BLENDFACTOR_ONE_MINUS_DST_COLOR = 0x8, /**< 1-dstR, 1-dstG, 1-dstB, 1-dstA */
- SDL_BLENDFACTOR_DST_ALPHA = 0x9, /**< dstA, dstA, dstA, dstA */
- SDL_BLENDFACTOR_ONE_MINUS_DST_ALPHA = 0xA /**< 1-dstA, 1-dstA, 1-dstA, 1-dstA */
- } SDL_BlendFactor;
-
- /**
- * Compose a custom blend mode for renderers.
- *
- * 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:
- *
- * ```c
- * 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 in
- * SDL 2.0.6. 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 with SDL
- * 2.0.6.
- * - **opengles**: Supports the `SDL_BLENDOPERATION_ADD` operation with all
- * factors. Color and alpha factors need to be the same. OpenGL ES 1
- * implementation specific: May also support `SDL_BLENDOPERATION_SUBTRACT`
- * and `SDL_BLENDOPERATION_REV_SUBTRACT`. May support color and alpha
- * operations being different from each other. May support color and alpha
- * factors being different from each other.
- * - **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.
- *
- * \param srcColorFactor the SDL_BlendFactor applied to the red, green, and
- * blue components of the source pixels
- * \param dstColorFactor the SDL_BlendFactor applied to the red, green, and
- * blue components of the destination pixels
- * \param colorOperation the SDL_BlendOperation used to combine the red,
- * green, and blue components of the source and
- * destination pixels
- * \param srcAlphaFactor the SDL_BlendFactor applied to the alpha component of
- * the source pixels
- * \param dstAlphaFactor the SDL_BlendFactor applied to the alpha component of
- * the destination pixels
- * \param 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.
- *
- * \since This function is available since SDL 2.0.6.
- *
- * \sa SDL_SetRenderDrawBlendMode
- * \sa SDL_GetRenderDrawBlendMode
- * \sa SDL_SetTextureBlendMode
- * \sa SDL_GetTextureBlendMode
- */
- extern DECLSPEC SDL_BlendMode SDLCALL SDL_ComposeCustomBlendMode(SDL_BlendFactor srcColorFactor,
- SDL_BlendFactor dstColorFactor,
- SDL_BlendOperation colorOperation,
- SDL_BlendFactor srcAlphaFactor,
- SDL_BlendFactor dstAlphaFactor,
- SDL_BlendOperation alphaOperation);
-
- /* Ends C function definitions when using C++ */
- #ifdef __cplusplus
- }
- #endif
- #include "close_code.h"
-
- #endif /* SDL_blendmode_h_ */
-
- /* vi: set ts=4 sw=4 expandtab: */
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