X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=docs%2Fegl.html;h=240cec53af17a63b3b73cc8160ccf7e28c0d01c8;hb=e52959e9612e6e645407c6256d35fac9c8fe3276;hp=e960309fc475957f7202030cd4bec314649e95b0;hpb=feb619b7705897ca723e8fe728f739932f743327;p=mesa.git diff --git a/docs/egl.html b/docs/egl.html index e960309fc47..240cec53af1 100644 --- a/docs/egl.html +++ b/docs/egl.html @@ -1,16 +1,24 @@ - - -Mesa EGL + + + + + Mesa EGL + + + - +
+

The Mesa 3D Graphics Library

+
- + +

Mesa EGL

The current version of EGL in Mesa implements EGL 1.4. More information about EGL can be found at - + http://www.khronos.org/egl/.

The Mesa's implementation of EGL uses a driver architecture. The main @@ -19,114 +27,122 @@ API entry points and helper functions for use by the drivers. Drivers are dynamically loaded by the main library and most of the EGL API calls are directly dispatched to the drivers.

-

The driver in use decides the window system to support. For drivers that -support hardware rendering, there are usually multiple drivers supporting the -same window system. Each one of of them supports a certain range of graphics -cards.

+

The driver in use decides the window system to support.

Build EGL

  1. -

    Run configure with the desired state trackers and enable -the Gallium driver for your hardware. For example

    +

    Run configure with the desired client APIs and enable +the driver for your hardware. For example

    -  $ ./configure --with-state-trackers=egl,es,vega --enable-gallium-{swrast,intel}
+  $ ./configure --enable-gles1 --enable-gles2 \
+                --with-dri-drivers=... \
+                --with-gallium-drivers=...
    -

    The main library will be enabled by default. The egl state -tracker is needed by a number of EGL drivers. EGL drivers will be covered -later. The es state tracker provides OpenGL ES 1.x -and 2.x and the vega state tracker provides OpenVG -1.x.

    +

    The main library and OpenGL is enabled by default. The first two options +above enables OpenGL ES 1.x and 2.x. The last two +options enables the listed classic and and Gallium drivers respectively.

    +
  2. Build and install Mesa as usual.

In the given example, it will build and install libEGL, -libGLESv1_CM, libGLESv2, libOpenVG, and -one or more EGL drivers.

+libGL, libGLESv1_CM, libGLESv2, and one +or more EGL drivers.

Configure Options

There are several options that control the build of EGL at configuration time

- +

These options enable OpenGL ES support in OpenGL. The result is one big +internal library that supports multiple APIs.

+ + + +
--enable-shared-glapi
+
-

OpenGL

+

By default, libGL has its own copy of libglapi. +This options makes libGL use the shared libglapi. This +is required if applications mix OpenGL and OpenGL ES.

-

The OpenGL state tracker is not built in the above example. It should be -noted that the classic libGL is not a state tracker and cannot be -used with EGL (unless the EGL driver in use is egl_glx). To build -the OpenGL state tracker, one may append glx to ---with-state-trackers and manually build -src/gallium/targets/libgl-xlib/.

+
+ +
--enable-openvg
+
+ +

OpenVG must be explicitly enabled by this option.

+ +
+ +

Use EGL

-

The demos for OpenGL ES and OpenVG can be found in progs/es1/, -progs/es2/ and progs/openvg/. You can use them to -test your build. For example,

+

Demos

-
-  $ cd progs/es1/xegl
-  $ make
-  $ ./torus
-
+

There are demos for the client APIs supported by EGL. They can be found in +mesa/demos repository.

Environment Variables

There are several environment variables that control the behavior of EGL at runtime

- + +

EGL Drivers

-

There are two categories of EGL drivers: Gallium and classic.

+
+
egl_dri2
+
+ +

This driver supports both x11 and drm platforms. +It functions as a DRI driver loader. For x11 support, it talks to +the X server directly using (XCB-)DRI2 protocol.

+ +

This driver can share DRI drivers with libGL.

-

Gallium EGL drivers supports all rendering APIs specified in EGL 1.4. The -support for optional EGL functions and EGL extensions is usually more complete -than the classic ones. These drivers depend on the egl state -tracker to build. The available drivers are

+
- +
egl_gallium
+
-

<dpy> is given by --with-egl-displays at -configuration time. There will be one EGL driver for each combination of the -displays listed and the hardware drivers enabled.

+

This driver is based on Gallium3D. It supports all rendering APIs and +hardwares supported by Gallium3D. It is the only driver that supports OpenVG. +The supported platforms are X11, DRM, FBDEV, and GDI.

-

Classic EGL drivers, on the other hand, supports only OpenGL as its -rendering API. They can be found under src/egl/drivers/. There -are 3 of them

+

This driver comes with its own hardware drivers +(pipe_<hw>) and client API modules +(st_<api>).

-
    -
  • egl_glx +
+ +
egl_glx
+

This driver provides a wrapper to GLX. It uses exclusively GLX to implement the EGL API. It supports both direct and indirect rendering when the GLX does. It is accelerated when the GLX is. As such, it cannot provide functions that is not available in GLX or GLX extensions.

- - -
  • egl_dri2 - -

    This driver supports the X Window System as its window system. It functions -as a DRI2 driver loader. Unlike egl_glx, it has no dependency on -libGL. It talks to the X server directly using DRI2 protocol.

    - -
    • -
  • egl_dri +
    • +
    -

    This driver lacks maintenance and does not build. It is similiar -to egl_dri2 in that it functions as a DRI(1) driver loader. But -unlike egl_dri2, it supports Linux framebuffer devices as its -window system and supports EGL_MESA_screen_surface extension. As DRI1 drivers -are phasing out, it might eventually be replaced by egl_dri2.

    +

    Packaging

    - - +

    The ABI between the main library and its drivers are not stable. Nor is +there a plan to stabilize it at the moment. Of the EGL drivers, +egl_gallium has its own hardware drivers and client API modules. +They are considered internal to egl_gallium and there is also no +stable ABI between them. These should be kept in mind when packaging for +distribution.

    -

    To use the classic drivers, one must manually set EGL_DRIVER at -runtime.

    +

    Generally, egl_dri2 is preferred over egl_gallium +when the system already has DRI drivers. As egl_gallium is loaded +before egl_dri2 when both are available, egl_gallium +is disabled by default.

    Developers

    @@ -311,14 +340,6 @@ not be called with the sample display at the same time. If a driver has access to an EGLDisplay without going through the EGL APIs, the driver should as well lock the display before using it. -

    TODOs

    - - - +