For initializing the mpv OpenGL state via MPV_RENDER_PARAM_OPENGL_INIT_PARAMS. More...

#include <render_gl.h>

Public Attributes
void (	get_proc_address )(void ctx, const char name)
	This retrieves OpenGL function pointers, and will use them in subsequent operation. More...

void *	get_proc_address_ctx
	Value passed as ctx parameter to get_proc_address(). More...

const char *	extra_exts
	This should not be used. More...

Detailed Description

For initializing the mpv OpenGL state via MPV_RENDER_PARAM_OPENGL_INIT_PARAMS.

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 the native display resource needs to be provided (e.g. MPV_RENDER_PARAM_X11_DISPLAY for X11 and MPV_RENDER_PARAM_WL_DISPLAY for Wayland)
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.

Definition at line 106 of file render_gl.h.

Member Data Documentation

◆ extra_exts

const char* mpv_opengl_init_params::extra_exts

This should not be used.

It is deprecated and will be removed or ignored when the opengl_cb API is removed.

Definition at line 127 of file render_gl.h.

◆ get_proc_address

void*(* mpv_opengl_init_params::get_proc_address) (void *ctx, const char *name)

This retrieves OpenGL function pointers, and will use them in subsequent operation.

Usually, you can simply call the GL context APIs from this callback (e.g. 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 when libmpv wants to resolve them through this callback. libmpv will not normally attempt to resolve GL functions on its own, nor does it link to GL libraries directly.

Definition at line 118 of file render_gl.h.

◆ get_proc_address_ctx

void* mpv_opengl_init_params::get_proc_address_ctx

Value passed as ctx parameter to get_proc_address().

Definition at line 122 of file render_gl.h.

The documentation for this struct was generated from the following file:

mpv-dev-x86_64-20200718/include/render_gl.h

Public Attributes