From 43f5a10f9c75c69fadccdf9d88e0102bd0ecaa5b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Sat, 8 Dec 2018 11:45:23 +0200
Subject: [PATCH] Add API for mapping GL buffers as VideoFrameRef in addition
 to a full VideoFrame

---
 gstreamer-gl/src/gl_video_frame.rs | 62 ++++++++++++++++++++++++++++++
 gstreamer-video/src/video_frame.rs | 18 +++++++++
 2 files changed, 80 insertions(+)

diff --git a/gstreamer-gl/src/gl_video_frame.rs b/gstreamer-gl/src/gl_video_frame.rs
index 680f6c12e..62ec01883 100644
--- a/gstreamer-gl/src/gl_video_frame.rs
+++ b/gstreamer-gl/src/gl_video_frame.rs
@@ -26,10 +26,35 @@ pub trait VideoFrameGLExt {
         info: &VideoInfo,
     ) -> Result<VideoFrame<Readable>, gst::Buffer>;
 
+    fn from_buffer_ref_readable_gl<'a, 'b>(
+        buffer: &'a gst::BufferRef,
+        info: &'b VideoInfo,
+    ) -> Option<VideoFrameRef<&'a gst::BufferRef>>;
+
     fn get_texture_id(&self, idx: u32) -> Option<u32>;
 }
 
 impl VideoFrameGLExt for VideoFrame<Readable> {
+    fn from_buffer_readable_gl(
+        buffer: gst::Buffer,
+        info: &VideoInfo,
+    ) -> Result<VideoFrame<Readable>, gst::Buffer> {
+        VideoFrameRef::<&gst::BufferRef>::from_buffer_readable_gl(buffer, info)
+    }
+
+    fn from_buffer_ref_readable_gl<'a, 'b>(
+        buffer: &'a gst::BufferRef,
+        info: &'b VideoInfo,
+    ) -> Option<VideoFrameRef<&'a gst::BufferRef>> {
+        VideoFrameRef::<&gst::BufferRef>::from_buffer_ref_readable_gl(buffer, info)
+    }
+
+    fn get_texture_id(&self, idx: u32) -> Option<u32> {
+        self.as_video_frame_ref().get_texture_id(idx)
+    }
+}
+
+impl<'a> VideoFrameGLExt for VideoFrameRef<&'a gst::BufferRef> {
     fn from_buffer_readable_gl(
         buffer: gst::Buffer,
         info: &VideoInfo,
@@ -67,6 +92,43 @@ impl VideoFrameGLExt for VideoFrame<Readable> {
         }
     }
 
+    fn from_buffer_ref_readable_gl<'b, 'c>(
+        buffer: &'b gst::BufferRef,
+        info: &'c VideoInfo,
+    ) -> Option<VideoFrameRef<&'b gst::BufferRef>> {
+        skip_assert_initialized!();
+
+        let n_mem = match buffer_n_gl_memory(buffer) {
+            Some(n) => n,
+            None => return None,
+        };
+
+        // FIXME: planes are not memories, in multiview use case,
+        // number of memories = planes * views, but the raw memory is
+        // not exposed in videoframe
+        if n_mem != info.n_planes() {
+            return None;
+        }
+
+        unsafe {
+            let mut frame = mem::zeroed();
+            let res: bool = from_glib(gst_video_ffi::gst_video_frame_map(
+                &mut frame,
+                info.to_glib_none().0 as *mut _,
+                buffer.as_mut_ptr(),
+                gst_video_ffi::GST_VIDEO_FRAME_MAP_FLAG_NO_REF
+                    | gst_ffi::GST_MAP_READ
+                    | ffi::GST_MAP_GL as u32,
+            ));
+
+            if !res {
+                None
+            } else {
+                Some(VideoFrameRef::from_glib_borrow(&frame))
+            }
+        }
+    }
+
     fn get_texture_id(&self, idx: u32) -> Option<u32> {
         let len = buffer_n_gl_memory(self.buffer())?;
 
diff --git a/gstreamer-video/src/video_frame.rs b/gstreamer-video/src/video_frame.rs
index 5b15122bb..32fbbaaac 100644
--- a/gstreamer-video/src/video_frame.rs
+++ b/gstreamer-video/src/video_frame.rs
@@ -345,6 +345,15 @@ impl<'a> VideoFrameRef<&'a gst::BufferRef> {
         &self.0
     }
 
+    pub unsafe fn from_glib_borrow(frame: *const ffi::GstVideoFrame) -> Self {
+        assert!(!frame.is_null());
+
+        let frame = ptr::read(frame);
+        let info = ::VideoInfo(ptr::read(&frame.info));
+        let buffer = gst::BufferRef::from_ptr(frame.buffer);
+        VideoFrameRef(frame, Some(buffer), info, false)
+    }
+
     pub fn from_buffer_ref_readable<'b>(
         buffer: &'a gst::BufferRef,
         info: &'b ::VideoInfo,
@@ -523,6 +532,15 @@ impl<'a> VideoFrameRef<&'a gst::BufferRef> {
 }
 
 impl<'a> VideoFrameRef<&'a mut gst::BufferRef> {
+    pub unsafe fn from_glib_borrow_mut(frame: *mut ffi::GstVideoFrame) -> Self {
+        assert!(!frame.is_null());
+
+        let frame = ptr::read(frame);
+        let info = ::VideoInfo(ptr::read(&frame.info));
+        let buffer = gst::BufferRef::from_mut_ptr(frame.buffer);
+        VideoFrameRef(frame, Some(buffer), info, false)
+    }
+
     pub fn from_buffer_ref_writable<'b>(
         buffer: &'a mut gst::BufferRef,
         info: &'b ::VideoInfo,