From a90f6d5d67fc556e8c2109b1ccec32c76fd36381 Mon Sep 17 00:00:00 2001
From: Matthew Waters <matthew@centricular.com>
Date: Thu, 20 Jul 2023 20:50:26 +1000
Subject: [PATCH] gl/format: add helper for returning the number of components
 in a GL format

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5109>
---
 girs/GstGL-1.0.gir                            | 26 ++++++++++++
 .../gst-libs/gst/gl/gstglformat.c             | 41 +++++++++++++++++++
 .../gst-libs/gst/gl/gstglformat.h             |  2 +
 3 files changed, 69 insertions(+)

diff --git a/girs/GstGL-1.0.gir b/girs/GstGL-1.0.gir
index b719d23a86..4cfec0bdab 100644
--- a/girs/GstGL-1.0.gir
+++ b/girs/GstGL-1.0.gir
@@ -3914,6 +3914,19 @@ See also: gst_gl_filter_render_to_target()</doc>
           </parameter>
         </parameters>
       </function>
+      <function name="n_components" c:identifier="gst_gl_format_n_components" version="1.24">
+        <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.h"/>
+        <return-value transfer-ownership="none">
+          <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.c">the number of components in a #GstGLFormat</doc>
+          <type name="guint" c:type="guint"/>
+        </return-value>
+        <parameters>
+          <parameter name="gl_format" transfer-ownership="none">
+            <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.c">the #GstGLFormat</doc>
+            <type name="GLFormat" c:type="GstGLFormat"/>
+          </parameter>
+        </parameters>
+      </function>
       <function name="type_from_sized_gl_format" c:identifier="gst_gl_format_type_from_sized_gl_format" version="1.16">
         <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.c">Get the unsized format and type from @format for usage in glReadPixels,
 glTex{Sub}Image*, glTexImage* and similar functions.</doc>
@@ -10757,6 +10770,19 @@ The returned #GstGLContext will be shared with a GStreamer created OpenGL contex
         </parameter>
       </parameters>
     </function>
+    <function name="gl_format_n_components" c:identifier="gst_gl_format_n_components" moved-to="GLFormat.n_components" version="1.24">
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.h"/>
+      <return-value transfer-ownership="none">
+        <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.c">the number of components in a #GstGLFormat</doc>
+        <type name="guint" c:type="guint"/>
+      </return-value>
+      <parameters>
+        <parameter name="gl_format" transfer-ownership="none">
+          <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.c">the #GstGLFormat</doc>
+          <type name="GLFormat" c:type="GstGLFormat"/>
+        </parameter>
+      </parameters>
+    </function>
     <function name="gl_format_type_from_sized_gl_format" c:identifier="gst_gl_format_type_from_sized_gl_format" moved-to="GLFormat.type_from_sized_gl_format" version="1.16">
       <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.c">Get the unsized format and type from @format for usage in glReadPixels,
 glTex{Sub}Image*, glTexImage* and similar functions.</doc>
diff --git a/subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.c b/subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.c
index 74ce48bd1b..4c7548bc4f 100644
--- a/subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.c
+++ b/subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.c
@@ -415,6 +415,47 @@ gst_gl_format_type_from_sized_gl_format (GstGLFormat format,
   }
 }
 
+/**
+ * gst_gl_format_n_components:
+ * @gl_format: the #GstGLFormat
+ *
+ * Returns: the number of components in a #GstGLFormat
+ *
+ * Since: 1.24
+ */
+guint
+gst_gl_format_n_components (GstGLFormat gl_format)
+{
+  switch (gl_format) {
+    case GST_GL_LUMINANCE:
+    case GST_GL_ALPHA:
+    case GST_GL_RED:
+    case GST_GL_R8:
+    case GST_GL_DEPTH_COMPONENT16:
+    case GST_GL_R16:
+      return 1;
+    case GST_GL_LUMINANCE_ALPHA:
+    case GST_GL_RG:
+    case GST_GL_RG8:
+    case GST_GL_DEPTH24_STENCIL8:
+    case GST_GL_RG16:
+      return 2;
+    case GST_GL_RGB:
+    case GST_GL_RGB8:
+    case GST_GL_RGB565:
+    case GST_GL_RGB16:
+      return 3;
+    case GST_GL_RGBA:
+    case GST_GL_RGBA8:
+    case GST_GL_RGBA16:
+    case GST_GL_RGB10_A2:
+      return 4;
+    default:
+      g_warn_if_reached ();
+      return 0;
+  }
+}
+
 /**
  * gst_gl_format_is_supported:
  * @context: a #GstGLContext
diff --git a/subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.h b/subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.h
index 0db5a1422a..c85061dee3 100644
--- a/subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.h
+++ b/subprojects/gst-plugins-base/gst-libs/gst/gl/gstglformat.h
@@ -154,6 +154,8 @@ void                    gst_gl_format_type_from_sized_gl_format     (GstGLFormat
 GST_GL_API
 gboolean                gst_gl_format_is_supported                  (GstGLContext * context,
                                                                      GstGLFormat format);
+GST_GL_API
+guint                   gst_gl_format_n_components                  (GstGLFormat gl_format);
 
 GST_GL_API
 GstGLTextureTarget      gst_gl_texture_target_from_string           (const gchar * str);