--- /dev/null
+/*
+ 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: */
projects / xonotic / darkplaces.git / blobdiff