gl: update docs for mixer move

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4608>

girs/GstGL-1.0.gir

@@ -1049,6 +1049,137 @@ function to allocate and OpenGL resources needed for your application</doc>
                                             to the texture</doc>
       </member>
     </bitfield>
+    <class name="GLBaseMixer" c:symbol-prefix="gl_base_mixer" c:type="GstGLBaseMixer" version="1.24" parent="GstVideo.VideoAggregator" abstract="1" glib:type-name="GstGLBaseMixer" glib:get-type="gst_gl_base_mixer_get_type" glib:type-struct="GLBaseMixerClass">
+      <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.c">#GstGLBaseMixer handles the nitty gritty details of retrieving an OpenGL
+context.  It provides some virtual methods to know when the OpenGL context
+is available and is not available within this element.</doc>
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+      <virtual-method name="gl_start" version="1.24">
+        <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h">called in the GL thread to setup the element GL state.</doc>
+        <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+        <return-value transfer-ownership="none">
+          <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h">whether the start was successful</doc>
+          <type name="gboolean" c:type="gboolean"/>
+        </return-value>
+        <parameters>
+          <instance-parameter name="mix" transfer-ownership="none">
+            <type name="GLBaseMixer" c:type="GstGLBaseMixer*"/>
+          </instance-parameter>
+        </parameters>
+      </virtual-method>
+      <virtual-method name="gl_stop" version="1.24">
+        <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h">called in the GL thread to setup the element GL state.</doc>
+        <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+        <return-value transfer-ownership="none">
+          <type name="none" c:type="void"/>
+        </return-value>
+        <parameters>
+          <instance-parameter name="mix" transfer-ownership="none">
+            <type name="GLBaseMixer" c:type="GstGLBaseMixer*"/>
+          </instance-parameter>
+        </parameters>
+      </virtual-method>
+      <method name="get_gl_context" c:identifier="gst_gl_base_mixer_get_gl_context" version="1.24">
+        <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+        <return-value transfer-ownership="full" nullable="1">
+          <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.c">the #GstGLContext found by @mix</doc>
+          <type name="GLContext" c:type="GstGLContext*"/>
+        </return-value>
+        <parameters>
+          <instance-parameter name="mix" transfer-ownership="none">
+            <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.c">a #GstGLBaseMixer</doc>
+            <type name="GLBaseMixer" c:type="GstGLBaseMixer*"/>
+          </instance-parameter>
+        </parameters>
+      </method>
+      <property name="context" version="1.24" transfer-ownership="none">
+        <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.c">The #GstGLContext in use by this #GstGLBaseMixer</doc>
+        <type name="GLContext"/>
+      </property>
+      <field name="parent">
+        <type name="GstVideo.VideoAggregator" c:type="GstVideoAggregator"/>
+      </field>
+      <field name="display">
+        <type name="GLDisplay" c:type="GstGLDisplay*"/>
+      </field>
+      <field name="context">
+        <type name="GLContext" c:type="GstGLContext*"/>
+      </field>
+      <field name="_padding" readable="0" private="1">
+        <array zero-terminated="0" fixed-size="4">
+          <type name="gpointer" c:type="gpointer"/>
+        </array>
+      </field>
+      <field name="priv" readable="0" private="1">
+        <type name="GLBaseMixerPrivate" c:type="GstGLBaseMixerPrivate*"/>
+      </field>
+    </class>
+    <record name="GLBaseMixerClass" c:type="GstGLBaseMixerClass" glib:is-gtype-struct-for="GLBaseMixer" version="1.24">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+      <field name="parent_class">
+        <type name="GstVideo.VideoAggregatorClass" c:type="GstVideoAggregatorClass"/>
+      </field>
+      <field name="supported_gl_api">
+        <type name="GLAPI" c:type="GstGLAPI"/>
+      </field>
+      <field name="gl_start">
+        <callback name="gl_start">
+          <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+          <return-value transfer-ownership="none">
+            <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h">whether the start was successful</doc>
+            <type name="gboolean" c:type="gboolean"/>
+          </return-value>
+          <parameters>
+            <parameter name="mix" transfer-ownership="none">
+              <type name="GLBaseMixer" c:type="GstGLBaseMixer*"/>
+            </parameter>
+          </parameters>
+        </callback>
+      </field>
+      <field name="gl_stop">
+        <callback name="gl_stop">
+          <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+          <return-value transfer-ownership="none">
+            <type name="none" c:type="void"/>
+          </return-value>
+          <parameters>
+            <parameter name="mix" transfer-ownership="none">
+              <type name="GLBaseMixer" c:type="GstGLBaseMixer*"/>
+            </parameter>
+          </parameters>
+        </callback>
+      </field>
+      <field name="_padding" readable="0" private="1">
+        <array zero-terminated="0" fixed-size="4">
+          <type name="gpointer" c:type="gpointer"/>
+        </array>
+      </field>
+    </record>
+    <class name="GLBaseMixerPad" c:symbol-prefix="gl_base_mixer_pad" c:type="GstGLBaseMixerPad" version="1.24" parent="GstVideo.VideoAggregatorPad" glib:type-name="GstGLBaseMixerPad" glib:get-type="gst_gl_base_mixer_pad_get_type" glib:type-struct="GLBaseMixerPadClass">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+      <field name="parent">
+        <type name="GstVideo.VideoAggregatorPad" c:type="GstVideoAggregatorPad"/>
+      </field>
+      <field name="_padding" readable="0" private="1">
+        <array zero-terminated="0" fixed-size="4">
+          <type name="gpointer" c:type="gpointer"/>
+        </array>
+      </field>
+    </class>
+    <record name="GLBaseMixerPadClass" c:type="GstGLBaseMixerPadClass" glib:is-gtype-struct-for="GLBaseMixerPad" version="1.24">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+      <field name="parent_class">
+        <type name="GstVideo.VideoAggregatorPadClass" c:type="GstVideoAggregatorPadClass"/>
+      </field>
+      <field name="_padding" readable="0" private="1">
+        <array zero-terminated="0" fixed-size="4">
+          <type name="gpointer" c:type="gpointer"/>
+        </array>
+      </field>
+    </record>
+    <record name="GLBaseMixerPrivate" c:type="GstGLBaseMixerPrivate" disguised="1">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+    </record>
     <class name="GLBaseSrc" c:symbol-prefix="gl_base_src" c:type="GstGLBaseSrc" version="1.18" parent="GstBase.PushSrc" abstract="1" glib:type-name="GstGLBaseSrc" glib:get-type="gst_gl_base_src_get_type" glib:type-struct="GLBaseSrcClass">
       <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasesrc.c">#GstGLBaseSrc handles the nitty gritty details of retrieving an OpenGL
 context. It also provided some wrappers around #GstBaseSrc's `start()` and
@@ -4563,6 +4694,181 @@ mappings between texture formats.</doc>
         </array>
       </field>
     </record>
+    <class name="GLMixer" c:symbol-prefix="gl_mixer" c:type="GstGLMixer" version="1.24" parent="GLBaseMixer" abstract="1" glib:type-name="GstGLMixer" glib:get-type="gst_gl_mixer_get_type" glib:type-struct="GLMixerClass">
+      <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.c">#GstGLMixer helps implement an element that operates on RGBA textures.</doc>
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+      <virtual-method name="process_buffers" version="1.24">
+        <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h">Perform operations on the input buffers to produce an
+output buffer.</doc>
+        <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+        <return-value transfer-ownership="none">
+          <type name="gboolean" c:type="gboolean"/>
+        </return-value>
+        <parameters>
+          <instance-parameter name="mix" transfer-ownership="none">
+            <type name="GLMixer" c:type="GstGLMixer*"/>
+          </instance-parameter>
+          <parameter name="outbuf" transfer-ownership="none">
+            <type name="Gst.Buffer" c:type="GstBuffer*"/>
+          </parameter>
+        </parameters>
+      </virtual-method>
+      <virtual-method name="process_textures" invoker="process_textures" version="1.24">
+        <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.c">Perform processing required and call #GstGLMixerClass::process_textures().
+Intended for use within implementations of
+#GstGLMixerClass::process_buffers().</doc>
+        <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+        <return-value transfer-ownership="none">
+          <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.c">whether processing of textures succeeded</doc>
+          <type name="gboolean" c:type="gboolean"/>
+        </return-value>
+        <parameters>
+          <instance-parameter name="mix" transfer-ownership="none">
+            <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.c">the #GstGLMixer</doc>
+            <type name="GLMixer" c:type="GstGLMixer*"/>
+          </instance-parameter>
+          <parameter name="out_tex" transfer-ownership="none">
+            <type name="GLMemory" c:type="GstGLMemory*"/>
+          </parameter>
+        </parameters>
+      </virtual-method>
+      <method name="get_framebuffer" c:identifier="gst_gl_mixer_get_framebuffer" version="1.24">
+        <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+        <return-value transfer-ownership="full">
+          <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.c">(nullable): The #GstGLFramebuffer in use by this @mix</doc>
+          <type name="GLFramebuffer" c:type="GstGLFramebuffer*"/>
+        </return-value>
+        <parameters>
+          <instance-parameter name="mix" transfer-ownership="none">
+            <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.c">the #GstGLMixer</doc>
+            <type name="GLMixer" c:type="GstGLMixer*"/>
+          </instance-parameter>
+        </parameters>
+      </method>
+      <method name="process_textures" c:identifier="gst_gl_mixer_process_textures" version="1.24">
+        <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.c">Perform processing required and call #GstGLMixerClass::process_textures().
+Intended for use within implementations of
+#GstGLMixerClass::process_buffers().</doc>
+        <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+        <return-value transfer-ownership="none">
+          <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.c">whether processing of textures succeeded</doc>
+          <type name="gboolean" c:type="gboolean"/>
+        </return-value>
+        <parameters>
+          <instance-parameter name="mix" transfer-ownership="none">
+            <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.c">the #GstGLMixer</doc>
+            <type name="GLMixer" c:type="GstGLMixer*"/>
+          </instance-parameter>
+          <parameter name="outbuf" transfer-ownership="none">
+            <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.c">output @GstBuffer</doc>
+            <type name="Gst.Buffer" c:type="GstBuffer*"/>
+          </parameter>
+        </parameters>
+      </method>
+      <field name="parent">
+        <type name="GLBaseMixer" c:type="GstGLBaseMixer"/>
+      </field>
+      <field name="out_caps">
+        <type name="Gst.Caps" c:type="GstCaps*"/>
+      </field>
+      <field name="priv" readable="0" private="1">
+        <type name="GLMixerPrivate" c:type="GstGLMixerPrivate*"/>
+      </field>
+      <field name="_padding" readable="0" private="1">
+        <array zero-terminated="0" fixed-size="4">
+          <type name="gpointer" c:type="gpointer"/>
+        </array>
+      </field>
+    </class>
+    <record name="GLMixerClass" c:type="GstGLMixerClass" glib:is-gtype-struct-for="GLMixer" version="1.24">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+      <field name="parent_class">
+        <type name="GLBaseMixerClass" c:type="GstGLBaseMixerClass"/>
+      </field>
+      <field name="process_buffers">
+        <callback name="process_buffers">
+          <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+          <return-value transfer-ownership="none">
+            <type name="gboolean" c:type="gboolean"/>
+          </return-value>
+          <parameters>
+            <parameter name="mix" transfer-ownership="none">
+              <type name="GLMixer" c:type="GstGLMixer*"/>
+            </parameter>
+            <parameter name="outbuf" transfer-ownership="none">
+              <type name="Gst.Buffer" c:type="GstBuffer*"/>
+            </parameter>
+          </parameters>
+        </callback>
+      </field>
+      <field name="process_textures">
+        <callback name="process_textures">
+          <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+          <return-value transfer-ownership="none">
+            <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.c">whether processing of textures succeeded</doc>
+            <type name="gboolean" c:type="gboolean"/>
+          </return-value>
+          <parameters>
+            <parameter name="mix" transfer-ownership="none">
+              <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.c">the #GstGLMixer</doc>
+              <type name="GLMixer" c:type="GstGLMixer*"/>
+            </parameter>
+            <parameter name="out_tex" transfer-ownership="none">
+              <type name="GLMemory" c:type="GstGLMemory*"/>
+            </parameter>
+          </parameters>
+        </callback>
+      </field>
+      <field name="_padding" readable="0" private="1">
+        <array zero-terminated="0" fixed-size="4">
+          <type name="gpointer" c:type="gpointer"/>
+        </array>
+      </field>
+      <method name="add_rgba_pad_templates" c:identifier="gst_gl_mixer_class_add_rgba_pad_templates" version="1.24">
+        <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.c">Adds the default RGBA pad templates to this class.  If you have any special
+template requirements like a different pad subclass or different supported
+caps, you should not call this function and add the pad templates yourself
+manually.</doc>
+        <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+        <return-value transfer-ownership="none">
+          <type name="none" c:type="void"/>
+        </return-value>
+        <parameters>
+          <instance-parameter name="klass" transfer-ownership="none">
+            <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.c">the #GstGLMixerClass</doc>
+            <type name="GLMixerClass" c:type="GstGLMixerClass*"/>
+          </instance-parameter>
+        </parameters>
+      </method>
+    </record>
+    <class name="GLMixerPad" c:symbol-prefix="gl_mixer_pad" c:type="GstGLMixerPad" version="1.24" parent="GLBaseMixerPad" glib:type-name="GstGLMixerPad" glib:get-type="gst_gl_mixer_pad_get_type" glib:type-struct="GLMixerPadClass">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+      <field name="parent">
+        <type name="GLBaseMixerPad" c:type="GstGLBaseMixerPad"/>
+      </field>
+      <field name="current_texture">
+        <type name="guint" c:type="guint"/>
+      </field>
+      <field name="_padding" readable="0" private="1">
+        <array zero-terminated="0" fixed-size="4">
+          <type name="gpointer" c:type="gpointer"/>
+        </array>
+      </field>
+    </class>
+    <record name="GLMixerPadClass" c:type="GstGLMixerPadClass" glib:is-gtype-struct-for="GLMixerPad" version="1.24">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+      <field name="parent_class">
+        <type name="GLBaseMixerPadClass" c:type="GstGLBaseMixerPadClass"/>
+      </field>
+      <field name="_padding" readable="0" private="1">
+        <array zero-terminated="0" fixed-size="4">
+          <type name="gpointer" c:type="gpointer"/>
+        </array>
+      </field>
+    </record>
+    <record name="GLMixerPrivate" c:type="GstGLMixerPrivate" disguised="1">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+    </record>
     <class name="GLOverlayCompositor" c:symbol-prefix="gl_overlay_compositor" c:type="GstGLOverlayCompositor" parent="Gst.Object" glib:type-name="GstGLOverlayCompositor" glib:get-type="gst_gl_overlay_compositor_get_type" glib:type-struct="GLOverlayCompositorClass">
       <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstgloverlaycompositor.h">Opaque #GstGLOverlayCompositor object</doc>
       <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstgloverlaycompositor.h"/>
@@ -9162,6 +9468,48 @@ user-defined purposes.</doc>
         </parameter>
       </parameters>
     </function-macro>
+    <function-macro name="GL_BASE_MIXER" c:identifier="GST_GL_BASE_MIXER" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+      <parameters>
+        <parameter name="obj">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="GL_BASE_MIXER_CLASS" c:identifier="GST_GL_BASE_MIXER_CLASS" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+      <parameters>
+        <parameter name="klass">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="GL_BASE_MIXER_GET_CLASS" c:identifier="GST_GL_BASE_MIXER_GET_CLASS" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+      <parameters>
+        <parameter name="obj">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="GL_BASE_MIXER_PAD" c:identifier="GST_GL_BASE_MIXER_PAD" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+      <parameters>
+        <parameter name="obj">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="GL_BASE_MIXER_PAD_CLASS" c:identifier="GST_GL_BASE_MIXER_PAD_CLASS" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+      <parameters>
+        <parameter name="klass">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="GL_BASE_MIXER_PAD_GET_CLASS" c:identifier="GST_GL_BASE_MIXER_PAD_GET_CLASS" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+      <parameters>
+        <parameter name="obj">
+        </parameter>
+      </parameters>
+    </function-macro>
     <function-macro name="GL_BASE_SRC" c:identifier="GST_GL_BASE_SRC" introspectable="0">
       <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasesrc.h"/>
       <parameters>
@@ -9507,6 +9855,48 @@ e.g. for `CONFIG_ID`: `GST_GL_CONFIG_ATTRIB_NAME (CONFIG_ID)`</doc>
       <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmemory.h"/>
       <type name="utf8" c:type="gchar*"/>
     </constant>
+    <function-macro name="GL_MIXER" c:identifier="GST_GL_MIXER" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+      <parameters>
+        <parameter name="obj">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="GL_MIXER_CLASS" c:identifier="GST_GL_MIXER_CLASS" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+      <parameters>
+        <parameter name="klass">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="GL_MIXER_GET_CLASS" c:identifier="GST_GL_MIXER_GET_CLASS" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+      <parameters>
+        <parameter name="obj">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="GL_MIXER_PAD" c:identifier="GST_GL_MIXER_PAD" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+      <parameters>
+        <parameter name="obj">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="GL_MIXER_PAD_CLASS" c:identifier="GST_GL_MIXER_PAD_CLASS" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+      <parameters>
+        <parameter name="klass">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="GL_MIXER_PAD_GET_CLASS" c:identifier="GST_GL_MIXER_PAD_GET_CLASS" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+      <parameters>
+        <parameter name="obj">
+        </parameter>
+      </parameters>
+    </function-macro>
     <function-macro name="GL_OVERLAY_COMPOSITOR" c:identifier="GST_GL_OVERLAY_COMPOSITOR" introspectable="0">
       <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstgloverlaycompositor.h"/>
       <parameters>
@@ -9748,6 +10138,34 @@ e.g. for `CONFIG_ID`: `GST_GL_CONFIG_ATTRIB_NAME (CONFIG_ID)`</doc>
         </parameter>
       </parameters>
     </function-macro>
+    <function-macro name="IS_GL_BASE_MIXER" c:identifier="GST_IS_GL_BASE_MIXER" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+      <parameters>
+        <parameter name="obj">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="IS_GL_BASE_MIXER_CLASS" c:identifier="GST_IS_GL_BASE_MIXER_CLASS" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+      <parameters>
+        <parameter name="klass">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="IS_GL_BASE_MIXER_PAD" c:identifier="GST_IS_GL_BASE_MIXER_PAD" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+      <parameters>
+        <parameter name="obj">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="IS_GL_BASE_MIXER_PAD_CLASS" c:identifier="GST_IS_GL_BASE_MIXER_PAD_CLASS" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h"/>
+      <parameters>
+        <parameter name="klass">
+        </parameter>
+      </parameters>
+    </function-macro>
     <function-macro name="IS_GL_BASE_SRC" c:identifier="GST_IS_GL_BASE_SRC" introspectable="0">
       <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasesrc.h"/>
       <parameters>
@@ -9881,6 +10299,34 @@ e.g. for `CONFIG_ID`: `GST_GL_CONFIG_ATTRIB_NAME (CONFIG_ID)`</doc>
         </parameter>
       </parameters>
     </function-macro>
+    <function-macro name="IS_GL_MIXER" c:identifier="GST_IS_GL_MIXER" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+      <parameters>
+        <parameter name="obj">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="IS_GL_MIXER_CLASS" c:identifier="GST_IS_GL_MIXER_CLASS" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+      <parameters>
+        <parameter name="klass">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="IS_GL_MIXER_PAD" c:identifier="GST_IS_GL_MIXER_PAD" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+      <parameters>
+        <parameter name="obj">
+        </parameter>
+      </parameters>
+    </function-macro>
+    <function-macro name="IS_GL_MIXER_PAD_CLASS" c:identifier="GST_IS_GL_MIXER_PAD_CLASS" introspectable="0">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h"/>
+      <parameters>
+        <parameter name="klass">
+        </parameter>
+      </parameters>
+    </function-macro>
     <function-macro name="IS_GL_OVERLAY_COMPOSITOR" c:identifier="GST_IS_GL_OVERLAY_COMPOSITOR" introspectable="0">
       <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstgloverlaycompositor.h"/>
       <parameters>

subprojects/gst-docs/symbols/symbol_index.json

@@ -10041,7 +10041,7 @@
   "GstGLBaseMemoryError",
   "GstGLBaseMemoryTransfer",
   "GstGLBaseMixer",
-  "GstGLBaseMixer:context",
+  "GstGLBaseMixerClass",
   "GstGLBaseMixerPad",
   "GstGLBaseSrc",
   "GstGLBaseSrc.context",
@@ -10311,7 +10311,9 @@
   "GstGLMixerBinStartTimeSelection::first",
   "GstGLMixerBinStartTimeSelection::set",
   "GstGLMixerBinStartTimeSelection::zero",
+  "GstGLMixerClass",
   "GstGLMixerPad",
+  "GstGLMixerPadClass",
   "GstGLMosaic",
   "GstGLMosaic!sink_%u",
   "GstGLMosaic!src",

subprojects/gst-plugins-base/docs/plugins/gst_plugins_cache.json

@@ -6882,43 +6882,6 @@
                     }
                 ]
             },
-            "GstGLBaseMixer": {
-                "hierarchy": [
-                    "GstGLBaseMixer",
-                    "GstVideoAggregator",
-                    "GstAggregator",
-                    "GstElement",
-                    "GstObject",
-                    "GInitiallyUnowned",
-                    "GObject"
-                ],
-                "kind": "object",
-                "properties": {
-                    "context": {
-                        "blurb": "Get OpenGL context",
-                        "conditionally-available": false,
-                        "construct": false,
-                        "construct-only": false,
-                        "controllable": false,
-                        "mutable": "null",
-                        "readable": true,
-                        "type": "GstGLContext",
-                        "writable": false
-                    }
-                }
-            },
-            "GstGLBaseMixerPad": {
-                "hierarchy": [
-                    "GstGLBaseMixerPad",
-                    "GstVideoAggregatorPad",
-                    "GstAggregatorPad",
-                    "GstPad",
-                    "GstObject",
-                    "GInitiallyUnowned",
-                    "GObject"
-                ],
-                "kind": "object"
-            },
             "GstGLDeinterlaceMethod": {
                 "kind": "enum",
                 "values": [
@@ -7047,19 +7010,6 @@
                     }
                 ]
             },
-            "GstGLMixer": {
-                "hierarchy": [
-                    "GstGLMixer",
-                    "GstGLBaseMixer",
-                    "GstVideoAggregator",
-                    "GstAggregator",
-                    "GstElement",
-                    "GstObject",
-                    "GInitiallyUnowned",
-                    "GObject"
-                ],
-                "kind": "object"
-            },
             "GstGLMixerBinStartTimeSelection": {
                 "kind": "enum",
                 "values": [
@@ -7080,21 +7030,6 @@
                     }
                 ]
             },
-            "GstGLMixerPad": {
-                "hierarchy": [
-                    "GstGLMixerPad",
-                    "GstGLBaseMixerPad",
-                    "GstVideoAggregatorPad",
-                    "GstAggregatorPad",
-                    "GstPad",
-                    "GstObject",
-                    "GInitiallyUnowned",
-                    "GObject"
-                ],
-                "kind": "object",
-                "properties": {},
-                "signals": {}
-            },
             "GstGLRotateMethod": {
                 "kind": "enum",
                 "values": [

subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.c

@@ -88,8 +88,6 @@ gst_gl_base_mixer_pad_class_init (GstGLBaseMixerPadClass * klass)
 
   vaggpad_class->prepare_frame = NULL;
   vaggpad_class->clean_frame = NULL;
-
-  gst_type_mark_as_plugin_api (GST_TYPE_GL_BASE_MIXER_PAD, 0);
 }
 
 static void
@@ -385,6 +383,13 @@ gst_gl_base_mixer_class_init (GstGLBaseMixerClass * klass)
   klass->gl_start = gst_gl_base_mixer_default_gl_start;
   klass->gl_stop = gst_gl_base_mixer_default_gl_stop;
 
+  /**
+   * GstGLBaseMixer:context:
+   *
+   * The #GstGLContext in use by this #GstGLBaseMixer
+   *
+   * Since: 1.24
+   */
   g_object_class_install_property (gobject_class, PROP_CONTEXT,
       g_param_spec_object ("context",
           "OpenGL context",
@@ -395,8 +400,6 @@ gst_gl_base_mixer_class_init (GstGLBaseMixerClass * klass)
   g_type_class_ref (GST_TYPE_GL_BASE_MIXER_PAD);
 
   klass->supported_gl_api = GST_GL_API_ANY;
-
-  gst_type_mark_as_plugin_api (GST_TYPE_GL_BASE_MIXER, 0);
 }
 
 static void

subprojects/gst-plugins-base/gst-libs/gst/gl/gstglbasemixer.h

@@ -43,15 +43,44 @@ G_BEGIN_DECLS
 typedef struct _GstGLBaseMixerPad GstGLBaseMixerPad;
 typedef struct _GstGLBaseMixerPadClass GstGLBaseMixerPadClass;
 
-/* all information needed for one video stream */
+/**
+ * GstGLBaseMixerPad:
+ *
+ * Since: 1.24
+ */
 struct _GstGLBaseMixerPad
 {
-  GstVideoAggregatorPad parent;                /* subclass the pad */
+  /**
+   * GstGLBaseMixerPad.parent:
+   *
+   * parent #GstVideoAggregatorPad
+   *
+   * Since: 1.24
+   */
+  GstVideoAggregatorPad parent;
+
+  /*< private >*/
+  gpointer _padding[GST_PADDING];
 };
 
+/**
+ * GstGLBaseMixerPadClass:
+ *
+ * Since: 1.24
+ */
 struct _GstGLBaseMixerPadClass
 {
+  /**
+   * GstGLBaseMixerPadClass.parent_class:
+   *
+   * parent #GstVideoAggregatorPadClass
+   *
+   * Since: 1.24
+   */
   GstVideoAggregatorPadClass parent_class;
+
+  /*< private >*/
+  gpointer _padding[GST_PADDING];
 };
 
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GstGLBaseMixerPad, gst_object_unref);
@@ -75,26 +104,89 @@ typedef struct _GstGLBaseMixer GstGLBaseMixer;
 typedef struct _GstGLBaseMixerClass GstGLBaseMixerClass;
 typedef struct _GstGLBaseMixerPrivate GstGLBaseMixerPrivate;
 
+/**
+ * GstGLBaseMixer:
+ *
+ * Since: 1.24
+ */
 struct _GstGLBaseMixer
 {
-  GstVideoAggregator     vaggregator;
+  /**
+   * GstGLBaseMixer.parent:
+   *
+   * parent #GstVideoAggregator
+   *
+   * Since: 1.24
+   */
+  GstVideoAggregator     parent;
 
+  /**
+   * GstGLBaseMixer.display:
+   *
+   * the currently configured #GstGLDisplay
+   *
+   * Since: 1.24
+   */
   GstGLDisplay          *display;
+  /**
+   * GstGLBaseMixer.context:
+   *
+   * the currently configured #GstGLContext
+   *
+   * Since: 1.24
+   */
   GstGLContext          *context;
 
+  /*< private >*/
   gpointer _padding[GST_PADDING];
 
   GstGLBaseMixerPrivate *priv;
 };
 
+/**
+ * GstGLBaseMixerClass:
+ *
+ * Since: 1.24
+ */
 struct _GstGLBaseMixerClass
 {
+  /**
+   * GstGLBaseMixerClass.parent_class:
+   *
+   * the parent #GstVideoAggregatorClass
+   *
+   * Since: 1.24
+   */
   GstVideoAggregatorClass parent_class;
+  /**
+   * GstGLBaseMixerClass.supported_gl_api:
+   *
+   * the logical-OR of #GstGLAPI's supported by this element
+   *
+   * Since: 1.24
+   */
   GstGLAPI supported_gl_api;
 
+  /**
+   * GstGLBaseMixerClass::gl_start:
+   *
+   * called in the GL thread to setup the element GL state.
+   *
+   * Returns: whether the start was successful
+   *
+   * Since: 1.24
+   */
   gboolean      (*gl_start)     (GstGLBaseMixer * mix);
+  /**
+   * GstGLBaseMixerClass::gl_stop:
+   *
+   * called in the GL thread to setup the element GL state.
+   *
+   * Since: 1.24
+   */
   void          (*gl_stop)      (GstGLBaseMixer * mix);
 
+  /*< private >*/
   gpointer _padding[GST_PADDING];
 };
 

subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.c

@@ -466,9 +466,6 @@ gst_gl_mixer_class_init (GstGLMixerClass * klass)
 
   /* Register the pad class */
   g_type_class_ref (GST_TYPE_GL_MIXER_PAD);
-
-  gst_type_mark_as_plugin_api (GST_TYPE_GL_MIXER_PAD, 0);
-  gst_type_mark_as_plugin_api (GST_TYPE_GL_MIXER, 0);
 }
 
 static void
@@ -673,6 +670,19 @@ context_error:
   }
 }
 
+/**
+ * gst_gl_mixer_process_textures:
+ * @mix: the #GstGLMixer
+ * @outbuf: output @GstBuffer
+ *
+ * Perform processing required and call #GstGLMixerClass::process_textures().
+ * Intended for use within implementations of
+ * #GstGLMixerClass::process_buffers().
+ *
+ * Returns: whether processing of textures succeeded
+ *
+ * Since: 1.24
+ */
 gboolean
 gst_gl_mixer_process_textures (GstGLMixer * mix, GstBuffer * outbuf)
 {

subprojects/gst-plugins-base/gst-libs/gst/gl/gstglmixer.h

@@ -46,17 +46,53 @@ typedef struct _GstGLMixerPrivate GstGLMixerPrivate;
 typedef struct _GstGLMixerPad GstGLMixerPad;
 typedef struct _GstGLMixerPadClass GstGLMixerPadClass;
 
-/* all information needed for one video stream */
+/**
+ * GstGLMixerPad:
+ *
+ * Since: 1.24
+ */
 struct _GstGLMixerPad
 {
+  /**
+   * GstGLMixerPad.parent:
+   *
+   * parent #GstGLBaseMixerPad
+   *
+   * Since: 1.24
+   */
   GstGLBaseMixerPad parent;
 
+  /**
+   * GstGLMixerPad.current_texture:
+   *
+   * the current input texture for this pad
+   *
+   * Since: 1.24
+   */
   guint current_texture;
+
+  /*< private >*/
+  gpointer _padding[GST_PADDING];
 };
 
+/**
+ * GstGLMixerPadClass:
+ *
+ * Since: 1.24
+ */
 struct _GstGLMixerPadClass
 {
+  /**
+   * GstGLMixerPadClass.parent_class:
+   *
+   * parent #GstGLBaseMixerPadClass
+   *
+   * Since: 1.24
+   */
   GstGLBaseMixerPadClass parent_class;
+
+  /*< private >*/
+  gpointer _padding[GST_PADDING];
 };
 
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GstGLMixerPad, gst_object_unref);
@@ -76,24 +112,71 @@ GType gst_gl_mixer_pad_get_type (void);
 #define GST_GL_MIXER_GET_CLASS(obj) \
         (G_TYPE_INSTANCE_GET_CLASS((obj),GST_TYPE_GL_MIXER,GstGLMixerClass))
 
-typedef gboolean (*GstGLMixerProcessFunc) (GstGLMixer *mix, GstBuffer *outbuf);
+/**
-typedef gboolean (*GstGLMixerProcessTextures) (GstGLMixer *mix, GstGLMemory *out_tex);
+ * GstGLMixer:
-
+ *
+ * Since: 1.24
+ */
 struct _GstGLMixer
 {
-  GstGLBaseMixer vaggregator;
+  /**
+   * GstGLMixer.parent:
+   *
+   * Since: 1.24
+   */
+  GstGLBaseMixer parent;
 
+  /**
+   * GstGLMixer.out_caps:
+   *
+   * the configured output #GstCaps
+   *
+   * Since: 1.24
+   */
   GstCaps *out_caps;
 
+  /*< private >*/
   GstGLMixerPrivate *priv;
+
+  /*< private >*/
+  gpointer _padding[GST_PADDING];
 };
 
+/**
+ * GstGLMixerClass:
+ *
+ * Since: 1.24
+ */
 struct _GstGLMixerClass
 {
+  /**
+   * GstGLMixerClass.parent_class:
+   *
+   * Since: 1.24
+   */
   GstGLBaseMixerClass parent_class;
 
-  GstGLMixerProcessFunc process_buffers;
+  /**
-  GstGLMixerProcessTextures process_textures;
+   * GstGLMixerClass::process_buffers:
+   *
+   * Perform operations on the input buffers to produce an
+   * output buffer.
+   *
+   * Since: 1.24
+   */
+  gboolean    (*process_buffers)      (GstGLMixer * mix, GstBuffer *outbuf);
+  /**
+   * GstGLMixerClass::process_textures:
+   *
+   * perform operations with the input and output buffers mapped
+   * as textures.  Will not be called if @process_buffers is overriden.
+   *
+   * Since: 1.24
+   */
+  gboolean    (*process_textures)     (GstGLMixer * mix, GstGLMemory *out_tex);
+
+  /*< private >*/
+  gpointer _padding[GST_PADDING];
 };
 
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GstGLMixer, gst_object_unref);