subs, vo: do sub bitmap change detection by comparing IDs

vo_vdpau and vo_gl cache the last subtitle bitmaps uploaded to video
card in case they stay the same over multiple frames. Detecting
whether the bitmaps have changed and should be re-uploaded was
somewhat fragile. Change the VO API to provide a bitmap ID which can
be compared with what the VO has to determine whether a new upload of
the bitmaps is needed.

Conflicts:
	libvo/vo_gl.c

Note: the changes for vo_gl.c were not merged. Instead, eosd_packer is
modified to use the new way of detecting EOSD changes. This takes care
of vo_gl, vo_gl3 and vo_direct3d, which all render EOSD. They don't
need to be updated in turn.

3 files changed, 16 insertions, 8 deletions

diff --git a/libvo/eosd_packer.c b/libvo/eosd_packer.c
index 103648b7c4..8f831d512e 100644
--- a/libvo/eosd_packer.c
+++ b/libvo/eosd_packer.c
@@ -147,17 +147,18 @@ void eosd_packer_generate(struct eosd_packer *state, mp_eosd_images_t *imgs,
     ASS_Image *p;
     struct eosd_surface *sfc = &state->surface;
 
-    *out_need_reposition = false;
-    *out_need_upload = false;
+    *out_need_reposition = imgs->bitmap_pos_id != state->last_bitmap_pos_id;
+    *out_need_upload = imgs->bitmap_id != state->last_bitmap_id;
     *out_need_reallocate = false;
 
-    int change_state = imgs->changed;
+    state->last_bitmap_pos_id = imgs->bitmap_pos_id;
+    state->last_bitmap_id = imgs->bitmap_id;
 
     // eosd_reinit() was probably called, force full reupload.
     if (state->targets_count == 0 && img)
-        change_state = 2;
+        *out_need_upload = true;
 
-    if (change_state == 0)
+    if (!(*out_need_reposition) && !(*out_need_upload))
         return; // Nothing changed, no need to redraw
 
     state->targets_count = 0;
@@ -167,7 +168,7 @@ void eosd_packer_generate(struct eosd_packer *state, mp_eosd_images_t *imgs,
     if (!img)
         return; // There's nothing to render!
 
-    if (change_state == 1)
+    if (!(*out_need_upload))
         goto eosd_skip_upload;
 
     *out_need_upload = true;
diff --git a/libvo/eosd_packer.h b/libvo/eosd_packer.h
index eaacd0223f..228057d3c4 100644
--- a/libvo/eosd_packer.h
+++ b/libvo/eosd_packer.h
@@ -58,6 +58,8 @@ struct eosd_packer {
     uint32_t max_surface_height;
 
     int *scratch;
+    int last_bitmap_id;
+    int last_bitmap_pos_id;
 };
 
 struct eosd_packer *eosd_packer_create(void *talloc_ctx);
diff --git a/libvo/vo_vdpau.c b/libvo/vo_vdpau.c
index d9b59c7dbe..922ec24201 100644
--- a/libvo/vo_vdpau.c
+++ b/libvo/vo_vdpau.c
@@ -186,6 +186,8 @@ struct vdpctx {
     } *eosd_targets, osd_targets[MAX_OLD_OSD_BITMAPS][2];
     int eosd_targets_size;
     int eosd_render_count;
+    int bitmap_id;
+    int bitmap_pos_id;
 
     // Video equalizer
     struct mp_csp_equalizer video_eq;
@@ -812,6 +814,7 @@ static void mark_vdpau_objects_uninitialized(struct vo *vo)
     vc->vdp_device = VDP_INVALID_HANDLE;
     talloc_free(vc->osd_surface.packer);
     talloc_free(vc->eosd_surface.packer);
+    vc->bitmap_id = vc->bitmap_pos_id = 0;
     vc->osd_surface = vc->eosd_surface = (struct eosd_bitmap_surface){
         .surface = VDP_INVALID_HANDLE,
     };
@@ -999,7 +1002,7 @@ static void generate_eosd(struct vo *vo, mp_eosd_images_t *imgs)
     struct eosd_bitmap_surface *sfc = &vc->eosd_surface;
     bool need_upload = false;
 
-    if (imgs->changed == 0 && sfc->packer)
+    if (imgs->bitmap_pos_id == vc->bitmap_pos_id)
         return; // Nothing changed and we still have the old data
 
     vc->eosd_render_count = 0;
@@ -1007,7 +1010,7 @@ static void generate_eosd(struct vo *vo, mp_eosd_images_t *imgs)
     if (!imgs->imgs)
         return; // There's nothing to render!
 
-    if (imgs->changed == 1)
+    if (imgs->bitmap_id == vc->bitmap_id)
         goto eosd_skip_upload;
 
     need_upload = true;
@@ -1069,6 +1072,8 @@ eosd_skip_upload:
         target->dest.y1 = p->h + p->dst_y;
         vc->eosd_render_count++;
     }
+    vc->bitmap_id = imgs->bitmap_id;
+    vc->bitmap_pos_id = imgs->bitmap_pos_id;
 }
 
 static void record_osd(void *ctx, int x0, int y0, int w, int h,