/* Copyright (C) 2017 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_OPENGL_CB_H_
#define MPV_CLIENT_API_OPENGL_CB_H_
#include "client.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
*
* Overview
* --------
*
* This API can be used to make mpv render into a foreign OpenGL context. It
* can be used to handle video display.
*
* The renderer needs to be explicitly initialized with mpv_opengl_cb_init_gl(),
* and then video can be drawn with mpv_opengl_cb_draw(). The user thread can
* be notified by new frames with mpv_opengl_cb_set_update_callback().
*
* You can output and embed video without this API by setting the mpv "wid"
* option to a native window handle (see "Embedding the video window" section
* in the client.h header). In general, using the opengl-cb API is recommended,
* because window embedding can cause various issues, especially with GUI
* toolkits and certain platforms.
*
* OpenGL interop
* --------------
*
* This assumes the OpenGL context lives on a certain thread controlled by the
* API user. The following functions require access to the OpenGL context:
* mpv_opengl_cb_init_gl
* mpv_opengl_cb_draw
* mpv_opengl_cb_uninit_gl
*
* The OpenGL context is indirectly accessed through the OpenGL function
* pointers returned by the get_proc_address callback in mpv_opengl_cb_init_gl.
* Generally, mpv will not load the system OpenGL library when using this API.
*
* Only "desktop" OpenGL version 2.1 or later is supported. With OpenGL 2.1,
* the GL_ARB_texture_rg is required. The renderer was written against
* OpenGL 3.x core profile, with additional support for OpenGL 2.1.
*
* Note that some hardware decoding interop API (as set with the "hwdec" option)
* may actually access
*
* 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.
*
* Threading
* ---------
*
* The mpv_opengl_cb_* functions can be called from any thread, under the
* following conditions:
* - only one of the mpv_opengl_cb_* functions can be called at the same time
* (unless they belong to different mpv cores created by mpv_create())
* - for functions which need an OpenGL context (see above) the OpenGL context
* must be "current" in the current thread, and it must be the same context
* as used with mpv_opengl_cb_init_gl()
* - never can be called from within the callbacks set with
* mpv_set_wakeup_callback() or mpv_opengl_cb_set_update_callback()
*
* Context and handle lifecycle
* ----------------------------
*
* Video initialization will fail if the OpenGL context was not initialized yet
* (with mpv_opengl_cb_init_gl()). Likewise, mpv_opengl_cb_uninit_gl() will
* disable video.
*
* When the mpv core is destroyed (e.g. via mpv_terminate_destroy()), the OpenGL
* context must have been uninitialized. If this doesn't happen, undefined
* behavior will result.
*
* Hardware decoding
* -----------------
*
* Hardware decoding via opengl_cb 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.)
*
* While "normal" mpv loads the OpenGL hardware decoding interop on demand,
* this can't be done with opengl_cb for internal technical reasons. Instead,
* make it load the interop at load time by setting the
* "opengl-hwdec-interop"="auto" option before calling mpv_opengl_cb_init_gl()
* ("hwdec-preload" in older mpv releases).
*
* 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: GLX is required (if you force "cuda", it should work on EGL
* as well, if you have recent enough drivers and the
* "hwaccel" option is set to "cuda" as well)
* - 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.
*
* Special windowing system interop considerations
* ------------------------------------------------
*
* In some cases, libmpv needs to have access to the windowing system's handles.
* This can be a pointer to a X11 "Display" for example. Usually this is needed
* only for hardware decoding.
*
* You can communicate these handles to libmpv by adding a pseudo-OpenGL
* extension "GL_MP_MPGetNativeDisplay" to the additional extension string when
* calling mpv_opengl_cb_init_gl(). The get_proc_address callback should resolve
* a function named "glMPGetNativeDisplay", which has the signature:
*
* void* GLAPIENTRY glMPGetNativeDisplay(const char* name)
*
* See below what names are defined. Usually, libmpv will use the native handle
* up until mpv_opengl_cb_uninit_gl() is called. If the name is not anything
* you know/expected, return NULL from the function.
*
* Windowing system interop on Intel/Linux with VAAPI
* --------------------------------------------------
*
* The new VAAPI OpenGL interop requires an EGL context. EGL provides no way
* to query the X11 Display associated to a specific EGL context, so this API
* is used to pass it through.
*
* glMPGetNativeDisplay("x11") should return a X11 "Display*", which then will
* be used to create the hardware decoder state.
*
* glMPGetNativeDisplay("wl") should return a Wayland "struct wl_display *".
*
* glMPGetNativeDisplay("drm") should return a DRM FD casted to intptr_t (note
* that a 0 FD is not supported - if this can happen in your case, you must
* dup2() it to a non-0 FD).
*
* nVidia/Linux via VDPAU requires GLX, which does not have this problem (the
* GLX API can return the current X11 Display).
*
* Windowing system interop on MS win32
* ------------------------------------
*
* You should use ANGLE, and make sure your application and libmpv are linked
* to the same ANGLE DLLs. libmpv will pick the device context (needed for
* hardware decoding) from the current ANGLE EGL context.
*
* Windowing system interop on RPI
* -------------------------------
*
* The RPI uses no proper interop, but hardware overlays instead. To place the
* overlay correctly, you can communicate the window parameters as follows to
* libmpv. glMPGetNativeDisplay("MPV_RPI_WINDOW") returns an array of type int
* with the following 4 elements:
* 0: display number (default 0)
* 1: layer number of the GL layer - video will be placed in the layer
* directly below (default: 0)
* 2: absolute x position of the GL context (default: 0)
* 3: absolute y position of the GL context (default: 0)
* The (x,y) position must be the absolute screen pixel position of the
* top/left pixel of the dispmanx layer used for the GL context. If you render
* to a FBO, the position must be that of the final position of the FBO
* contents on screen. You can't transform or scale the video other than what
* mpv will render to the video overlay. The defaults are suitable for
* rendering the video at fullscreen.
* The parameters are checked on every draw by calling MPGetNativeDisplay and
* checking the values in the returned array for changes. The returned array
* must remain valid until the libmpv render function returns; then it can be
* deallocated by the API user.
*/
/**
* Opaque context, returned by mpv_get_sub_api(MPV_SUB_API_OPENGL_CB).
*
* A context is bound to the mpv_handle it was retrieved from. The context
* will always be the same (for the same mpv_handle), and is valid until the
* mpv_handle it belongs to is released.
*/
typedef struct mpv_opengl_cb_context mpv_opengl_cb_context;
typedef void (*mpv_opengl_cb_update_fn)(void *cb_ctx);
typedef void *(*mpv_opengl_cb_get_proc_address_fn)(void *fn_ctx, const char *name);
/**
* Set the callback that notifies you when a new video frame is available, or
* if the video display configuration somehow changed and requires a redraw.
* Similar to mpv_set_wakeup_callback(), you must not call any mpv API from
* the callback.
*
* @param callback callback(callback_ctx) is called if the frame should be
* redrawn
* @param callback_ctx opaque argument to the callback
*/
void mpv_opengl_cb_set_update_callback(mpv_opengl_cb_context *ctx,
mpv_opengl_cb_update_fn callback,
void *callback_ctx);
/**
* Initialize the mpv OpenGL state. This retrieves OpenGL function pointers via
* get_proc_address, and creates OpenGL objects needed by mpv internally. It
* will also call APIs needed for rendering hardware decoded video in OpenGL,
* according to the mpv "hwdec" option.
*
* You must free the associated state at some point by calling the
* mpv_opengl_cb_uninit_gl() function. Not doing so may result in memory leaks
* or worse.
*
* @param exts optional _additional_ extension string, can be NULL
* @param get_proc_address callback used to retrieve function pointers to OpenGL
* functions. This is used for both standard functions
* and extension functions. (The extension string is
* checked whether extensions are really available.)
* The callback will be called from this function only
* (it is not stored and never used later).
* 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.
* @param get_proc_address_ctx arbitrary opaque user context passed to the
* get_proc_address callback
* @return error code (same as normal mpv_* API), including but not limited to:
* MPV_ERROR_UNSUPPORTED: the OpenGL version is not supported
* (or required extensions are missing)
* MPV_ERROR_INVALID_PARAMETER: the OpenGL state was already initialized
*/
int mpv_opengl_cb_init_gl(mpv_opengl_cb_context *ctx, const char *exts,
mpv_opengl_cb_get_proc_address_fn get_proc_address,
void *get_proc_address_ctx);
/**
* Render video. Requires that the OpenGL state is initialized.
*
* The video will use the full provided framebuffer. Options like "panscan" are
* applied to determine which part of the video should be visible and how the
* video should be scaled. You can change these options at runtime by using the
* mpv property API.
*
* The renderer will reconfigure itself every time the output rectangle/size
* is changed. (If you want to do animations, it might be better to do the
* animation on a FBO instead.)
*
* This function implicitly pulls a video frame from the internal queue and
* renders it. If no new frame is available, the previous frame is redrawn.
* The update callback set with mpv_opengl_cb_set_update_callback() notifies
* you when a new frame was added.
*
* @param fbo The framebuffer object to render on. Because the renderer might
* manage multiple FBOs internally for the purpose of video
* postprocessing, it will always bind and unbind FBOs itself. If
* you want mpv to render on the main framebuffer, pass 0.
* @param w Width of the framebuffer. This is either the video size if the fbo
* parameter is 0, or the allocated size of the texture backing the
* fbo. The renderer will always use the full size of the fbo.
* @param h Height of the framebuffer. Same as with the w parameter, except
* that this parameter can be negative. In this case, the video
* frame will be rendered flipped.
* @return 0
*/
int mpv_opengl_cb_draw(mpv_opengl_cb_context *ctx, int fbo, int w, int h);
#if MPV_ENABLE_DEPRECATED
/**
* Deprecated. Use mpv_opengl_cb_draw(). This function is equivalent to:
*
* int mpv_opengl_cb_render(mpv_opengl_cb_context *ctx, int fbo, int vp[4])
* { return mpv_opengl_cb_draw(ctx, fbo, vp[2], vp[3]); }
*
* vp[0] and vp[1] used to have a meaning, but are ignored in newer versions.
*
* This function will be removed in the future without version bump (this API
* was never marked as stable).
*/
int mpv_opengl_cb_render(mpv_opengl_cb_context *ctx, int fbo, int vp[4]);
#endif
/**
* Tell the renderer that a frame was flipped at the given time. This is
* optional, but can help the player to achieve better timing.
*
* Note that calling this at least once informs libmpv that you will use this
* function. If you use it inconsistently, expect bad video playback.
*
* If this is called while no video or no OpenGL is initialized, it is ignored.
*
* @param time The mpv time (using mpv_get_time_us()) at which the flip call
* returned. If 0 is passed, mpv_get_time_us() is used instead.
* Currently, this parameter is ignored.
* @return error code
*/
int mpv_opengl_cb_report_flip(mpv_opengl_cb_context *ctx, int64_t time);
/**
* Destroy the mpv OpenGL state.
*
* If video is still active (e.g. a file playing), video will be disabled
* forcefully.
*
* Calling this multiple times is ok.
*
* @return error code
*/
int mpv_opengl_cb_uninit_gl(mpv_opengl_cb_context *ctx);
#ifdef __cplusplus
}
#endif
#endif