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/* Copyright (C) 2018 the mpv developers
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#ifndef MPV_CLIENT_API_RENDER_GL_H_
#define MPV_CLIENT_API_RENDER_GL_H_
#include "render.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* OpenGL backend
* --------------
*
* This header contains definitions for using OpenGL with the render.h API.
*
* OpenGL interop
* --------------
*
* The OpenGL backend has some special rules, because OpenGL itself uses
* implicit per-thread contexts, which causes additional API problems.
*
* This assumes the OpenGL context lives on a certain thread controlled by the
* API user. All mpv_render_* APIs have to be assumed to implicitly use the
* OpenGL context if you pass a mpv_render_context using the OpenGL backend,
* unless specified otherwise.
*
* The OpenGL context is indirectly accessed through the OpenGL function
* pointers returned by the get_proc_address callback in mpv_opengl_init_params.
* Generally, mpv will not load the system OpenGL library when using this API.
*
* OpenGL state
* ------------
*
* OpenGL has a large amount of implicit state. All the mpv functions mentioned
* above expect that the OpenGL state is reasonably set to OpenGL standard
* defaults. Likewise, mpv will attempt to leave the OpenGL context with
* standard defaults. The following state is excluded from this:
*
* - the glViewport state
* - the glScissor state (but GL_SCISSOR_TEST is in its default value)
* - glBlendFuncSeparate() state (but GL_BLEND is in its default value)
* - glClearColor() state
* - mpv may overwrite the callback set with glDebugMessageCallback()
* - mpv always disables GL_DITHER at init
*
* Messing with the state could be avoided by creating shared OpenGL contexts,
* but this is avoided for the sake of compatibility and interoperability.
*
* On OpenGL 2.1, mpv will strictly call functions like glGenTextures() to
* create OpenGL objects. You will have to do the same. This ensures that
* objects created by mpv and the API users don't clash. Also, legacy state
* must be either in its defaults, or not interfere with core state.
*
* API use
* -------
*
* The mpv_render_* API is used. That API supports multiple backends, and this
* section documents specifics for the OpenGL backend.
*
* Use mpv_render_context_create() with MPV_RENDER_PARAM_API_TYPE set to
* MPV_RENDER_API_TYPE_OPENGL, and MPV_RENDER_PARAM_OPENGL_INIT_PARAMS provided.
*
* Call mpv_render_context_render() with MPV_RENDER_PARAM_OPENGL_FBO to render
* the video frame to an FBO.
*
* Hardware decoding
* -----------------
*
* Hardware decoding via this API is fully supported, but requires some
* additional setup. (At least if direct hardware decoding modes are wanted,
* instead of copying back surface data from GPU to CPU RAM.)
*
* There may be certain requirements on the OpenGL implementation:
*
* - Windows: ANGLE is required (although in theory GL/DX interop could be used)
* - Intel/Linux: EGL is required, and also a glMPGetNativeDisplay() callback
* must be provided (see sections below)
* - nVidia/Linux: Both GLX and EGL should work (GLX is required if vdpau is
* used, e.g. due to old drivers.)
* - OSX: CGL is required (CGLGetCurrentContext() returning non-NULL)
* - iOS: EAGL is required (EAGLContext.currentContext returning non-nil)
*
* Once these things are setup, hardware decoding can be enabled/disabled at
* any time by setting the "hwdec" property.
*/
/**
* For initializing the mpv OpenGL state via MPV_RENDER_PARAM_OPENGL_INIT_PARAMS.
*/
typedef struct mpv_opengl_init_params {
/**
* This retrieves OpenGL function pointers, and will use them in subsequent
* operation.
* Usually, GL context APIs do this for you (e.g. with glXGetProcAddressARB
* or wglGetProcAddress), but some APIs do not always return pointers for
* all standard functions (even if present); in this case you have to
* compensate by looking up these functions yourself and returning them
* from this callback.
*/
void *(*get_proc_address)(void *ctx, const char *name);
/**
* Value passed as ctx parameter to get_proc_address().
*/
void *get_proc_address_ctx;
/**
* This should not be used. The main purpose is signaling support for
* "GL_MP_MPGetNativeDisplay", which is needed for compatibility with the
* opengl_cb API only. Thus it's deprecated and will be removed or ignored
* when the opengl_cb API is removed.
*/
const char *extra_exts;
} mpv_opengl_init_params;
/**
* For MPV_RENDER_PARAM_OPENGL_FBO.
*/
typedef struct mpv_opengl_fbo {
/**
* Framebuffer object name. This must be either a valid FBO generated by
* glGenFramebuffers() that is complete and color-renderable, or 0. If the
* value is 0, this refers to the OpenGL default framebuffer.
*/
int fbo;
/**
* Valid dimensions. This must refer to the size of the framebuffer. This
* must always be set.
*/
int w, h;
/**
* Underlying texture internal format (e.g. GL_RGBA8), or 0 if unknown. If
* this is the default framebuffer, this can be an equivalent.
*/
int internal_format;
} mpv_opengl_fbo;
#ifdef __cplusplus
}
#endif
#endif
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