SDL 2.0
SDL_blendmode.h
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1/*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
4
5 This software is provided 'as-is', without any express or implied
6 warranty. In no event will the authors be held liable for any damages
7 arising from the use of this software.
8
9 Permission is granted to anyone to use this software for any purpose,
10 including commercial applications, and to alter it and redistribute it
11 freely, subject to the following restrictions:
12
13 1. The origin of this software must not be misrepresented; you must not
14 claim that you wrote the original software. If you use this software
15 in a product, an acknowledgment in the product documentation would be
16 appreciated but is not required.
17 2. Altered source versions must be plainly marked as such, and must not be
18 misrepresented as being the original software.
19 3. This notice may not be removed or altered from any source distribution.
20*/
21
22/**
23 * # CategoryBlendmode
24 *
25 * Header file declaring the SDL_BlendMode enumeration
26 */
27
28#ifndef SDL_blendmode_h_
29#define SDL_blendmode_h_
30
31#include "begin_code.h"
32/* Set up for C function definitions, even when using C++ */
33#ifdef __cplusplus
34extern "C" {
35#endif
36
37/**
38 * The blend mode used in SDL_RenderCopy() and drawing operations.
39 */
40typedef enum SDL_BlendMode
41{
42 SDL_BLENDMODE_NONE = 0x00000000, /**< no blending
43 dstRGBA = srcRGBA */
44 SDL_BLENDMODE_BLEND = 0x00000001, /**< alpha blending
45 dstRGB = (srcRGB * srcA) + (dstRGB * (1-srcA))
46 dstA = srcA + (dstA * (1-srcA)) */
47 SDL_BLENDMODE_ADD = 0x00000002, /**< additive blending
48 dstRGB = (srcRGB * srcA) + dstRGB
49 dstA = dstA */
50 SDL_BLENDMODE_MOD = 0x00000004, /**< color modulate
51 dstRGB = srcRGB * dstRGB
52 dstA = dstA */
53 SDL_BLENDMODE_MUL = 0x00000008, /**< color multiply
54 dstRGB = (srcRGB * dstRGB) + (dstRGB * (1-srcA))
55 dstA = dstA */
56 SDL_BLENDMODE_INVALID = 0x7FFFFFFF
57
58 /* Additional custom blend modes can be returned by SDL_ComposeCustomBlendMode() */
59
61
62/**
63 * The blend operation used when combining source and destination pixel
64 * components
65 */
67{
68 SDL_BLENDOPERATION_ADD = 0x1, /**< dst + src: supported by all renderers */
69 SDL_BLENDOPERATION_SUBTRACT = 0x2, /**< src - dst : supported by D3D9, D3D11, OpenGL, OpenGLES */
70 SDL_BLENDOPERATION_REV_SUBTRACT = 0x3, /**< dst - src : supported by D3D9, D3D11, OpenGL, OpenGLES */
71 SDL_BLENDOPERATION_MINIMUM = 0x4, /**< min(dst, src) : supported by D3D9, D3D11 */
72 SDL_BLENDOPERATION_MAXIMUM = 0x5 /**< max(dst, src) : supported by D3D9, D3D11 */
74
75/**
76 * The normalized factor used to multiply pixel components
77 */
78typedef enum SDL_BlendFactor
79{
80 SDL_BLENDFACTOR_ZERO = 0x1, /**< 0, 0, 0, 0 */
81 SDL_BLENDFACTOR_ONE = 0x2, /**< 1, 1, 1, 1 */
82 SDL_BLENDFACTOR_SRC_COLOR = 0x3, /**< srcR, srcG, srcB, srcA */
83 SDL_BLENDFACTOR_ONE_MINUS_SRC_COLOR = 0x4, /**< 1-srcR, 1-srcG, 1-srcB, 1-srcA */
84 SDL_BLENDFACTOR_SRC_ALPHA = 0x5, /**< srcA, srcA, srcA, srcA */
85 SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA = 0x6, /**< 1-srcA, 1-srcA, 1-srcA, 1-srcA */
86 SDL_BLENDFACTOR_DST_COLOR = 0x7, /**< dstR, dstG, dstB, dstA */
87 SDL_BLENDFACTOR_ONE_MINUS_DST_COLOR = 0x8, /**< 1-dstR, 1-dstG, 1-dstB, 1-dstA */
88 SDL_BLENDFACTOR_DST_ALPHA = 0x9, /**< dstA, dstA, dstA, dstA */
89 SDL_BLENDFACTOR_ONE_MINUS_DST_ALPHA = 0xA /**< 1-dstA, 1-dstA, 1-dstA, 1-dstA */
91
92/**
93 * Compose a custom blend mode for renderers.
94 *
95 * The functions SDL_SetRenderDrawBlendMode and SDL_SetTextureBlendMode accept
96 * the SDL_BlendMode returned by this function if the renderer supports it.
97 *
98 * A blend mode controls how the pixels from a drawing operation (source) get
99 * combined with the pixels from the render target (destination). First, the
100 * components of the source and destination pixels get multiplied with their
101 * blend factors. Then, the blend operation takes the two products and
102 * calculates the result that will get stored in the render target.
103 *
104 * Expressed in pseudocode, it would look like this:
105 *
106 * ```c
107 * dstRGB = colorOperation(srcRGB * srcColorFactor, dstRGB * dstColorFactor);
108 * dstA = alphaOperation(srcA * srcAlphaFactor, dstA * dstAlphaFactor);
109 * ```
110 *
111 * Where the functions `colorOperation(src, dst)` and `alphaOperation(src,
112 * dst)` can return one of the following:
113 *
114 * - `src + dst`
115 * - `src - dst`
116 * - `dst - src`
117 * - `min(src, dst)`
118 * - `max(src, dst)`
119 *
120 * The red, green, and blue components are always multiplied with the first,
121 * second, and third components of the SDL_BlendFactor, respectively. The
122 * fourth component is not used.
123 *
124 * The alpha component is always multiplied with the fourth component of the
125 * SDL_BlendFactor. The other components are not used in the alpha
126 * calculation.
127 *
128 * Support for these blend modes varies for each renderer. To check if a
129 * specific SDL_BlendMode is supported, create a renderer and pass it to
130 * either SDL_SetRenderDrawBlendMode or SDL_SetTextureBlendMode. They will
131 * return with an error if the blend mode is not supported.
132 *
133 * This list describes the support of custom blend modes for each renderer in
134 * SDL 2.0.6. All renderers support the four blend modes listed in the
135 * SDL_BlendMode enumeration.
136 *
137 * - **direct3d**: Supports all operations with all factors. However, some
138 * factors produce unexpected results with `SDL_BLENDOPERATION_MINIMUM` and
139 * `SDL_BLENDOPERATION_MAXIMUM`.
140 * - **direct3d11**: Same as Direct3D 9.
141 * - **opengl**: Supports the `SDL_BLENDOPERATION_ADD` operation with all
142 * factors. OpenGL versions 1.1, 1.2, and 1.3 do not work correctly with SDL
143 * 2.0.6.
144 * - **opengles**: Supports the `SDL_BLENDOPERATION_ADD` operation with all
145 * factors. Color and alpha factors need to be the same. OpenGL ES 1
146 * implementation specific: May also support `SDL_BLENDOPERATION_SUBTRACT`
147 * and `SDL_BLENDOPERATION_REV_SUBTRACT`. May support color and alpha
148 * operations being different from each other. May support color and alpha
149 * factors being different from each other.
150 * - **opengles2**: Supports the `SDL_BLENDOPERATION_ADD`,
151 * `SDL_BLENDOPERATION_SUBTRACT`, `SDL_BLENDOPERATION_REV_SUBTRACT`
152 * operations with all factors.
153 * - **psp**: No custom blend mode support.
154 * - **software**: No custom blend mode support.
155 *
156 * Some renderers do not provide an alpha component for the default render
157 * target. The `SDL_BLENDFACTOR_DST_ALPHA` and
158 * `SDL_BLENDFACTOR_ONE_MINUS_DST_ALPHA` factors do not have an effect in this
159 * case.
160 *
161 * \param srcColorFactor the SDL_BlendFactor applied to the red, green, and
162 * blue components of the source pixels.
163 * \param dstColorFactor the SDL_BlendFactor applied to the red, green, and
164 * blue components of the destination pixels.
165 * \param colorOperation the SDL_BlendOperation used to combine the red,
166 * green, and blue components of the source and
167 * destination pixels.
168 * \param srcAlphaFactor the SDL_BlendFactor applied to the alpha component of
169 * the source pixels.
170 * \param dstAlphaFactor the SDL_BlendFactor applied to the alpha component of
171 * the destination pixels.
172 * \param alphaOperation the SDL_BlendOperation used to combine the alpha
173 * component of the source and destination pixels.
174 * \returns an SDL_BlendMode that represents the chosen factors and
175 * operations.
176 *
177 * \since This function is available since SDL 2.0.6.
178 *
179 * \sa SDL_SetRenderDrawBlendMode
180 * \sa SDL_GetRenderDrawBlendMode
181 * \sa SDL_SetTextureBlendMode
182 * \sa SDL_GetTextureBlendMode
183 */
184extern DECLSPEC SDL_BlendMode SDLCALL SDL_ComposeCustomBlendMode(SDL_BlendFactor srcColorFactor,
185 SDL_BlendFactor dstColorFactor,
186 SDL_BlendOperation colorOperation,
187 SDL_BlendFactor srcAlphaFactor,
188 SDL_BlendFactor dstAlphaFactor,
189 SDL_BlendOperation alphaOperation);
190
191/* Ends C function definitions when using C++ */
192#ifdef __cplusplus
193}
194#endif
195#include "close_code.h"
196
197#endif /* SDL_blendmode_h_ */
198
199/* vi: set ts=4 sw=4 expandtab: */
SDL_BlendOperation
@ SDL_BLENDOPERATION_MAXIMUM
@ SDL_BLENDOPERATION_MINIMUM
@ SDL_BLENDOPERATION_REV_SUBTRACT
@ SDL_BLENDOPERATION_ADD
@ SDL_BLENDOPERATION_SUBTRACT
SDL_BlendMode
@ SDL_BLENDMODE_NONE
@ SDL_BLENDMODE_ADD
@ SDL_BLENDMODE_BLEND
@ SDL_BLENDMODE_INVALID
@ SDL_BLENDMODE_MUL
@ SDL_BLENDMODE_MOD
SDL_BlendMode SDL_ComposeCustomBlendMode(SDL_BlendFactor srcColorFactor, SDL_BlendFactor dstColorFactor, SDL_BlendOperation colorOperation, SDL_BlendFactor srcAlphaFactor, SDL_BlendFactor dstAlphaFactor, SDL_BlendOperation alphaOperation)
SDL_BlendFactor
@ SDL_BLENDFACTOR_ONE_MINUS_SRC_COLOR
@ SDL_BLENDFACTOR_ZERO
@ SDL_BLENDFACTOR_SRC_COLOR
@ SDL_BLENDFACTOR_SRC_ALPHA
@ SDL_BLENDFACTOR_ONE_MINUS_DST_COLOR
@ SDL_BLENDFACTOR_ONE_MINUS_DST_ALPHA
@ SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA
@ SDL_BLENDFACTOR_DST_ALPHA
@ SDL_BLENDFACTOR_DST_COLOR
@ SDL_BLENDFACTOR_ONE