1/*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2024 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 * \file SDL_blendmode.h
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 * \brief The blend mode used in SDL_RenderCopy() and drawing operations.
39 */
40typedef enum
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
60} SDL_BlendMode;
61
62/**
63 * \brief The blend operation used when combining source and destination pixel components
64 */
65typedef enum
66{
67 SDL_BLENDOPERATION_ADD = 0x1, /**< dst + src: supported by all renderers */
68 SDL_BLENDOPERATION_SUBTRACT = 0x2, /**< src - dst : supported by D3D9, D3D11, OpenGL, OpenGLES */
69 SDL_BLENDOPERATION_REV_SUBTRACT = 0x3, /**< dst - src : supported by D3D9, D3D11, OpenGL, OpenGLES */
70 SDL_BLENDOPERATION_MINIMUM = 0x4, /**< min(dst, src) : supported by D3D9, D3D11 */
71 SDL_BLENDOPERATION_MAXIMUM = 0x5 /**< max(dst, src) : supported by D3D9, D3D11 */
72} SDL_BlendOperation;
73
74/**
75 * \brief The normalized factor used to multiply pixel components
76 */
77typedef enum
78{
79 SDL_BLENDFACTOR_ZERO = 0x1, /**< 0, 0, 0, 0 */
80 SDL_BLENDFACTOR_ONE = 0x2, /**< 1, 1, 1, 1 */
81 SDL_BLENDFACTOR_SRC_COLOR = 0x3, /**< srcR, srcG, srcB, srcA */
82 SDL_BLENDFACTOR_ONE_MINUS_SRC_COLOR = 0x4, /**< 1-srcR, 1-srcG, 1-srcB, 1-srcA */
83 SDL_BLENDFACTOR_SRC_ALPHA = 0x5, /**< srcA, srcA, srcA, srcA */
84 SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA = 0x6, /**< 1-srcA, 1-srcA, 1-srcA, 1-srcA */
85 SDL_BLENDFACTOR_DST_COLOR = 0x7, /**< dstR, dstG, dstB, dstA */
86 SDL_BLENDFACTOR_ONE_MINUS_DST_COLOR = 0x8, /**< 1-dstR, 1-dstG, 1-dstB, 1-dstA */
87 SDL_BLENDFACTOR_DST_ALPHA = 0x9, /**< dstA, dstA, dstA, dstA */
88 SDL_BLENDFACTOR_ONE_MINUS_DST_ALPHA = 0xA /**< 1-dstA, 1-dstA, 1-dstA, 1-dstA */
89} SDL_BlendFactor;
90
91/**
92 * Compose a custom blend mode for renderers.
93 *
94 * The functions SDL_SetRenderDrawBlendMode and SDL_SetTextureBlendMode accept
95 * the SDL_BlendMode returned by this function if the renderer supports it.
96 *
97 * A blend mode controls how the pixels from a drawing operation (source) get
98 * combined with the pixels from the render target (destination). First, the
99 * components of the source and destination pixels get multiplied with their
100 * blend factors. Then, the blend operation takes the two products and
101 * calculates the result that will get stored in the render target.
102 *
103 * Expressed in pseudocode, it would look like this:
104 *
105 * ```c
106 * dstRGB = colorOperation(srcRGB * srcColorFactor, dstRGB * dstColorFactor);
107 * dstA = alphaOperation(srcA * srcAlphaFactor, dstA * dstAlphaFactor);
108 * ```
109 *
110 * Where the functions `colorOperation(src, dst)` and `alphaOperation(src,
111 * dst)` can return one of the following:
112 *
113 * - `src + dst`
114 * - `src - dst`
115 * - `dst - src`
116 * - `min(src, dst)`
117 * - `max(src, dst)`
118 *
119 * The red, green, and blue components are always multiplied with the first,
120 * second, and third components of the SDL_BlendFactor, respectively. The
121 * fourth component is not used.
122 *
123 * The alpha component is always multiplied with the fourth component of the
124 * SDL_BlendFactor. The other components are not used in the alpha
125 * calculation.
126 *
127 * Support for these blend modes varies for each renderer. To check if a
128 * specific SDL_BlendMode is supported, create a renderer and pass it to
129 * either SDL_SetRenderDrawBlendMode or SDL_SetTextureBlendMode. They will
130 * return with an error if the blend mode is not supported.
131 *
132 * This list describes the support of custom blend modes for each renderer in
133 * SDL 2.0.6. All renderers support the four blend modes listed in the
134 * SDL_BlendMode enumeration.
135 *
136 * - **direct3d**: Supports all operations with all factors. However, some
137 * factors produce unexpected results with `SDL_BLENDOPERATION_MINIMUM` and
138 * `SDL_BLENDOPERATION_MAXIMUM`.
139 * - **direct3d11**: Same as Direct3D 9.
140 * - **opengl**: Supports the `SDL_BLENDOPERATION_ADD` operation with all
141 * factors. OpenGL versions 1.1, 1.2, and 1.3 do not work correctly with SDL
142 * 2.0.6.
143 * - **opengles**: Supports the `SDL_BLENDOPERATION_ADD` operation with all
144 * factors. Color and alpha factors need to be the same. OpenGL ES 1
145 * implementation specific: May also support `SDL_BLENDOPERATION_SUBTRACT`
146 * and `SDL_BLENDOPERATION_REV_SUBTRACT`. May support color and alpha
147 * operations being different from each other. May support color and alpha
148 * factors being different from each other.
149 * - **opengles2**: Supports the `SDL_BLENDOPERATION_ADD`,
150 * `SDL_BLENDOPERATION_SUBTRACT`, `SDL_BLENDOPERATION_REV_SUBTRACT`
151 * operations with all factors.
152 * - **psp**: No custom blend mode support.
153 * - **software**: No custom blend mode support.
154 *
155 * Some renderers do not provide an alpha component for the default render
156 * target. The `SDL_BLENDFACTOR_DST_ALPHA` and
157 * `SDL_BLENDFACTOR_ONE_MINUS_DST_ALPHA` factors do not have an effect in this
158 * case.
159 *
160 * \param srcColorFactor the SDL_BlendFactor applied to the red, green, and
161 * blue components of the source pixels
162 * \param dstColorFactor the SDL_BlendFactor applied to the red, green, and
163 * blue components of the destination pixels
164 * \param colorOperation the SDL_BlendOperation used to combine the red,
165 * green, and blue components of the source and
166 * destination pixels
167 * \param srcAlphaFactor the SDL_BlendFactor applied to the alpha component of
168 * the source pixels
169 * \param dstAlphaFactor the SDL_BlendFactor applied to the alpha component of
170 * the destination pixels
171 * \param alphaOperation the SDL_BlendOperation used to combine the alpha
172 * component of the source and destination pixels
173 * \returns an SDL_BlendMode that represents the chosen factors and
174 * operations.
175 *
176 * \since This function is available since SDL 2.0.6.
177 *
178 * \sa SDL_SetRenderDrawBlendMode
179 * \sa SDL_GetRenderDrawBlendMode
180 * \sa SDL_SetTextureBlendMode
181 * \sa SDL_GetTextureBlendMode
182 */
183extern DECLSPEC SDL_BlendMode SDLCALL SDL_ComposeCustomBlendMode(SDL_BlendFactor srcColorFactor,
184 SDL_BlendFactor dstColorFactor,
185 SDL_BlendOperation colorOperation,
186 SDL_BlendFactor srcAlphaFactor,
187 SDL_BlendFactor dstAlphaFactor,
188 SDL_BlendOperation alphaOperation);
189
190/* Ends C function definitions when using C++ */
191#ifdef __cplusplus
192}
193#endif
194#include "close_code.h"
195
196#endif /* SDL_blendmode_h_ */
197
198/* vi: set ts=4 sw=4 expandtab: */
199