sub: create sub_bitmap array even when using libass

One sub_bitmaps struct could contain either a libass ASS_Image list, or
a mplayer native list of sub-bitmaps. This caused code duplication in
vo_vdpau.c and bitmap_packer.c.

Avoid this by creating such a sub_bitmap array even with libass. This
basically copies the list and recreates it in mplayer's native format.
It gets rid of the code duplication, and will make implementing extended
subtitle and OSD rendering in other VOs easier.

Also do some cosmetic changes and other preparations for the following
commits.

4 files changed, 67 insertions, 18 deletions

diff --git a/sub/dec_sub.c b/sub/dec_sub.c
index 4a048b27a6..31b06b9b80 100644
--- a/sub/dec_sub.c
+++ b/sub/dec_sub.c
@@ -62,7 +62,8 @@ void sub_get_bitmaps(struct osd_state *osd, struct sub_bitmaps *res)
 {
     struct MPOpts *opts = osd->opts;
 
-    *res = (struct sub_bitmaps){ .type = SUBBITMAP_EMPTY,
+    *res = (struct sub_bitmaps){ .render_index = 0,
+                                 .format = SUBBITMAP_EMPTY,
                                  .bitmap_id = osd->bitmap_id,
                                  .bitmap_pos_id = osd->bitmap_pos_id };
     if (!opts->sub_visibility || !osd->sh_sub || !osd->sh_sub->active) {
diff --git a/sub/dec_sub.h b/sub/dec_sub.h
index c71a2348aa..df6aaf9b91 100644
--- a/sub/dec_sub.h
+++ b/sub/dec_sub.h
@@ -1,14 +1,22 @@
 #ifndef MPLAYER_DEC_SUB_H
 #define MPLAYER_DEC_SUB_H
 
+#include <stdbool.h>
+#include <stdint.h>
+
+#define MAX_OSD_PARTS 8
+
 struct sh_sub;
 struct osd_state;
 struct ass_track;
 
-enum sub_bitmap_type {
+enum sub_bitmap_format {
     SUBBITMAP_EMPTY,
-    SUBBITMAP_LIBASS,
-    SUBBITMAP_RGBA,
+    SUBBITMAP_LIBASS,   // A8, with a per-surface blend color (libass.color)
+    SUBBITMAP_RGBA,     // B8G8R8A8
+    SUBBITMAP_OLD,      // I8A8 (monochrome), premultiplied alpha
+
+    SUBBITMAP_COUNT
 };
 
 typedef struct mp_eosd_res {
@@ -16,21 +24,34 @@ typedef struct mp_eosd_res {
     int mt, mb, ml, mr; // borders (top, bottom, left, right)
 } mp_eosd_res_t;
 
+struct sub_bitmap {
+    void *bitmap;
+    int stride;
+    int w, h;
+    int x, y;
+    // Note: not clipped, going outside the screen area is allowed
+    int dw, dh;
+
+    union {
+        struct {
+            uint32_t color;
+        } libass;
+    };
+};
+
 typedef struct sub_bitmaps {
-    enum sub_bitmap_type type;
+    int render_index;   // for VO cache state (limited by MAX_OSD_PARTS)
 
-    struct ass_image *imgs;
+    enum sub_bitmap_format format;
+    bool scaled;        // if false, dw==w && dh==h
 
-    struct sub_bitmap {
-        int w, h;
-        int x, y;
-        // Note: not clipped, going outside the screen area is allowed
-        int dw, dh;
-        void *bitmap;
-    } *parts;
-    int part_count;
+    struct sub_bitmap *parts;
+    int num_parts;
+
+    // Provided for VOs with old code
+    struct ass_image *imgs;
 
-    bool scaled;
+    // Incremented on each change
     int bitmap_id, bitmap_pos_id;
 } mp_eosd_images_t;
 
diff --git a/sub/sd_ass.c b/sub/sd_ass.c
index 9295cab07d..aa190ee4ac 100644
--- a/sub/sd_ass.c
+++ b/sub/sd_ass.c
@@ -36,6 +36,7 @@ struct sd_ass_priv {
     struct ass_track *ass_track;
     bool vsfilter_aspect;
     bool incomplete_event;
+    struct sub_bitmap *parts;
 };
 
 static void free_last_event(ASS_Track *track)
@@ -147,7 +148,32 @@ static void get_bitmaps(struct sh_sub *sh, struct osd_state *osd,
         res->bitmap_id = ++res->bitmap_pos_id;
     else if (changed)
         res->bitmap_pos_id++;
-    res->type = SUBBITMAP_LIBASS;
+    res->format = SUBBITMAP_LIBASS;
+
+    int num_parts = 0;
+    int num_parts_alloc = MP_TALLOC_ELEMS(ctx->parts);
+    struct ass_image *img = res->imgs;
+    while (img) {
+        if (img->w == 0 || img->h == 0)
+            continue;
+        if (num_parts >= num_parts_alloc) {
+            num_parts_alloc = FFMAX(num_parts_alloc * 2, 32);
+            ctx->parts = talloc_realloc(ctx, ctx->parts, struct sub_bitmap,
+                                        num_parts_alloc);
+        }
+        struct sub_bitmap *p = &ctx->parts[num_parts];
+        p->bitmap = img->bitmap;
+        p->stride = img->stride;
+        p->libass.color = img->color;
+        p->dw = p->w = img->w;
+        p->dh = p->h = img->h;
+        p->x = img->dst_x;
+        p->y = img->dst_y;
+        img = img->next;
+        num_parts++;
+    }
+    res->parts = ctx->parts;
+    res->num_parts = num_parts;
 }
 
 static void reset(struct sh_sub *sh, struct osd_state *osd)
diff --git a/sub/sd_lavc.c b/sub/sd_lavc.c
index 1da33ffca1..39e4891fb1 100644
--- a/sub/sd_lavc.c
+++ b/sub/sd_lavc.c
@@ -175,6 +175,7 @@ static void decode(struct sh_sub *sh, struct osd_state *osd, void *data,
                 uint32_t *outbmp = talloc_size(priv->inbitmaps,
                                                r->w * r->h * 4);
                 b->bitmap = outbmp;
+                b->stride = r->w * 4;
                 b->w = r->w;
                 b->h = r->h;
                 b->x = r->x;
@@ -233,13 +234,13 @@ static void get_bitmaps(struct sh_sub *sh, struct osd_state *osd,
         SET(bo->dh, bi->h * yscale);
     }
     res->parts = priv->outbitmaps;
-    res->part_count = priv->count;
+    res->num_parts = priv->count;
     if (priv->bitmaps_changed)
         res->bitmap_id = ++res->bitmap_pos_id;
     else if (pos_changed)
         res->bitmap_pos_id++;
     priv->bitmaps_changed = false;
-    res->type = SUBBITMAP_RGBA;
+    res->format = SUBBITMAP_RGBA;
     res->scaled = xscale != 1 || yscale != 1;
 }