From 6b23fe3aa7efb0b58afa846ae7217df4ac24cb9d Mon Sep 17 00:00:00 2001
From: Christian Hergert <chergert@redhat.com>
Date: Fri, 18 Mar 2022 12:48:43 -0700
Subject: [PATCH] gsk/gl: pin atlases to single texture library

This removes the sharing of atlases across various texture libraries. Doing
so is necessary so that atlases can have different semantics for how they
allocate within the texture as well as potentially allowing for different
formats of texture data.

For example, in the future we might store non-pixel data in the textures
such as Glyphy or even keep glyphs with color content separate from glyphs
which do not and can use alpha channel only.
---
 gsk/gl/gskgltexturelibrary.c        | 24 +++++++++++++++---------
 gsk/gl/gskgltexturelibraryprivate.h |  1 +
 2 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/gsk/gl/gskgltexturelibrary.c b/gsk/gl/gskgltexturelibrary.c
index 8951f78829..649f422b0d 100644
--- a/gsk/gl/gskgltexturelibrary.c
+++ b/gsk/gl/gskgltexturelibrary.c
@@ -54,6 +54,7 @@ gsk_gl_texture_library_dispose (GObject *object)
 {
   GskGLTextureLibrary *self = (GskGLTextureLibrary *)object;
 
+  g_clear_pointer (&self->atlases, g_ptr_array_unref);
   g_clear_object (&self->driver);
 
   G_OBJECT_CLASS (gsk_gl_texture_library_parent_class)->dispose (object);
@@ -123,6 +124,7 @@ gsk_gl_texture_library_init (GskGLTextureLibrary *self)
   self->max_frame_age = DEFAULT_MAX_FRAME_AGE;
   self->atlas_width = DEFAULT_ATLAS_WIDTH;
   self->atlas_height = DEFAULT_ATLAS_HEIGHT;
+  self->atlases = g_ptr_array_new ();
 }
 
 void
@@ -157,6 +159,10 @@ gsk_gl_texture_library_begin_frame (GskGLTextureLibrary *self,
       GskGLTextureAtlasEntry *entry;
       guint dropped = 0;
 
+      /* Remove cached copy of purged atlases */
+      for (guint i = 0; i < removed_atlases->len; i++)
+        g_ptr_array_remove (self->atlases, g_ptr_array_index (removed_atlases, i));
+
       g_hash_table_iter_init (&iter, self->hash_table);
       while (g_hash_table_iter_next (&iter, NULL, (gpointer *)&entry))
         {
@@ -271,8 +277,8 @@ gsk_gl_texture_atlas_pack (GskGLTextureAtlas *self,
 }
 
 static void
-gsk_gl_texture_atlas_initialize (GskGLDriver       *driver,
-                                 GskGLTextureAtlas *atlas)
+gsk_gl_texture_library_init_atlas (GskGLTextureLibrary *self,
+                                   GskGLTextureAtlas   *atlas)
 {
   /* Insert a single pixel at 0,0 for use in coloring */
 
@@ -282,6 +288,8 @@ gsk_gl_texture_atlas_initialize (GskGLDriver       *driver,
   guint gl_type;
   guint8 pixel_data[4 * 3 * 3];
 
+  g_ptr_array_add (self->atlases, atlas);
+
   gdk_gl_context_push_debug_group_printf (gdk_gl_context_get_current (),
                                           "Initializing Atlas");
 
@@ -312,7 +320,7 @@ gsk_gl_texture_atlas_initialize (GskGLDriver       *driver,
 
   gdk_gl_context_pop_debug_group (gdk_gl_context_get_current ());
 
-  driver->command_queue->n_uploads++;
+  self->driver->command_queue->n_uploads++;
 }
 
 static void
@@ -323,13 +331,12 @@ gsk_gl_texture_atlases_pack (GskGLTextureLibrary *self,
                              int                 *out_x,
                              int                 *out_y)
 {
-  GskGLDriver *driver = self->driver;
   GskGLTextureAtlas *atlas = NULL;
   int x, y;
 
-  for (guint i = 0; i < driver->atlases->len; i++)
+  for (guint i = 0; i < self->atlases->len; i++)
     {
-      atlas = g_ptr_array_index (driver->atlases, i);
+      atlas = g_ptr_array_index (self->atlases, i);
 
       if (gsk_gl_texture_atlas_pack (atlas, width, height, &x, &y))
         break;
@@ -340,9 +347,8 @@ gsk_gl_texture_atlases_pack (GskGLTextureLibrary *self,
   if (atlas == NULL)
     {
       /* No atlas has enough space, so create a new one... */
-      atlas = gsk_gl_driver_create_atlas (driver, self->atlas_width, self->atlas_height);
-
-      gsk_gl_texture_atlas_initialize (driver, atlas);
+      atlas = gsk_gl_driver_create_atlas (self->driver, self->atlas_width, self->atlas_height);
+      gsk_gl_texture_library_init_atlas (self, atlas);
 
       /* Pack it onto that one, which surely has enough space... */
       if (!gsk_gl_texture_atlas_pack (atlas, width, height, &x, &y))
diff --git a/gsk/gl/gskgltexturelibraryprivate.h b/gsk/gl/gskgltexturelibraryprivate.h
index 26a35bd4af..167b00923b 100644
--- a/gsk/gl/gskgltexturelibraryprivate.h
+++ b/gsk/gl/gskgltexturelibraryprivate.h
@@ -90,6 +90,7 @@ typedef struct _GskGLTextureLibrary
 {
   GObject      parent_instance;
   GskGLDriver *driver;
+  GPtrArray   *atlases;
   GHashTable  *hash_table;
   guint        max_entry_size;
   guint        max_frame_age;
-- 
2.30.2