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diff --git a/docs/egl.html b/docs/egl.html index 305e5f6eab..57b1d1488a 100644 --- a/docs/egl.html +++ b/docs/egl.html @@ -223,9 +223,43 @@ runtime.</p> <h2>Developers</h2> -The sources of the main library and the classic drivers can be found at +<p>The sources of the main library and the classic drivers can be found at <code>src/egl/</code>. The sources of the <code>egl</code> state tracker can -be found at <code>src/gallium/state_trackers/egl/</code>. +be found at <code>src/gallium/state_trackers/egl/</code>.</p> + +<p>The suggested way to learn to write a EGL driver is to see how other drivers +are written. <code>egl_glx</code> should be a good reference. It works in any +environment that has GLX support, and it is simpler than most drivers.</p> + +<h3>Lifetime of Display Resources</h3> + +<p>Contexts and surfaces are examples of display resources. They might live +longer than the display that creates them.</p> + +<p>In EGL, when a display is terminated through <code>eglTerminate</code>, all +display resources should be destroyed. Similarly, when a thread is released +throught <code>eglReleaseThread</code>, all current display resources should be +released. Another way to destory or release resources is through functions +such as <code>eglDestroySurface</code> or <code>eglMakeCurrent</code>.</p> + +<p>When a resource that is current to some thread is destroyed, the resource +should not be destroyed immediately. EGL requires the resource to live until +it is no longer current. A driver usually calls +<code>eglIs<Resource>Bound</code> to check if a resource is bound +(current) to any thread in the destroy callbacks. If it is still bound, the +resource is not destroyed.</p> + +<p>The main library will mark destroyed current resources as unlinked. In a +driver's <code>MakeCurrent</code> callback, +<code>eglIs<Resource>Linked</code> can then be called to check if a newly +released resource is linked to a display. If it is not, the last reference to +the resource is removed and the driver should destroy the resource. But it +should be careful here because <code>MakeCurrent</code> might be called with an +uninitialized display.</p> + +<p>This is the only mechanism provided by the main library to help manage the +resources. The drivers are responsible to the correct behavior as defined by +EGL.</p> <h3>TODOs</h3> |