[gtk/wip/chergert/glproto: 650/920] add texture pool

[Christian Hergert <chergert src gnome org>]

commit 142b721db88760a49f6c733623824f4a7e41d5c8
Author: Christian Hergert <chergert redhat com>
Date:   Thu Jan 7 20:29:13 2021 -0800

    add texture pool
    
    the goal here is to keep the pooling code out of the driver just so that
    it is a bit easier to reason about going forward.
    
    also, pool is a much less overloaded term here compared to cache when
    dealing with textures.

 gsk/meson.build                    |   1 +
 gsk/next/gskgltexturepool.c        | 185 +++++++++++++++++++++++++++++++++++++
 gsk/next/gskgltexturepoolprivate.h |  69 ++++++++++++++
 3 files changed, 255 insertions(+)
---
diff --git a/gsk/meson.build b/gsk/meson.build
index 8b63ccbb65..6c1f4c7566 100644
--- a/gsk/meson.build
+++ b/gsk/meson.build
@@ -62,6 +62,7 @@ gsk_private_sources = files([
   'next/gskgltextureatlas.c',
   'next/gskgltexturelibrary.c',
   'next/gskgluniformstate.c',
+  'next/gskgltexturepool.c',
 ])
 
 gsk_public_headers = files([
diff --git a/gsk/next/gskgltexturepool.c b/gsk/next/gskgltexturepool.c
new file mode 100644
index 0000000000..219539219e
--- /dev/null
+++ b/gsk/next/gskgltexturepool.c
@@ -0,0 +1,185 @@
+/* gskgltexturepool.c
+ *
+ * Copyright 2020 Christian Hergert <chergert redhat com>
+ *
+ * This file is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation; either version 2.1 of the License, or (at your option)
+ * any later version.
+ *
+ * This file is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+#include "config.h"
+
+#include <string.h>
+
+#include "gskgltexturepoolprivate.h"
+
+static void
+gsk_gl_texture_free (GskGLTexture *texture)
+{
+  if (texture->texture_id != 0)
+    {
+      glDeleteTextures (1, &texture->texture_id);
+      texture->texture_id = 0;
+    }
+
+  g_slice_free (GskGLTexture, texture);
+}
+
+void
+gsk_gl_texture_pool_init (GskGLTexturePool *self)
+{
+  memset (self, 0, sizeof *self);
+}
+
+void
+gsk_gl_texture_pool_clear (GskGLTexturePool *self)
+{
+  while (self->by_width.length > 0)
+    {
+      GskGLTexture *head = g_queue_peek_head (&self->by_width);
+
+      g_queue_unlink (&self->by_width, &head->width_link);
+      g_queue_unlink (&self->by_height, &head->height_link);
+
+      gsk_gl_texture_free (head);
+    }
+
+  g_assert (self->by_width.length == 0);
+  g_assert (self->by_height.length == 0);
+}
+
+void
+gsk_gl_texture_pool_put (GskGLTexturePool *self,
+                         GskGLTexture     *texture)
+{
+  GList *sibling = NULL;
+
+  g_return_if_fail (self != NULL);
+  g_return_if_fail (texture != NULL);
+
+  for (GList *iter = self->by_width.head;
+       iter != NULL;
+       iter = iter->next)
+    {
+      GskGLTexture *other = iter->data;
+
+      if (other->width > texture->width ||
+          (other->width == texture->width &&
+           other->height > texture->height))
+        break;
+
+      sibling = iter;
+    }
+
+  g_queue_insert_after_link (&self->by_width, sibling, &texture->width_link);
+
+  for (GList *iter = self->by_width.head;
+       iter != NULL;
+       iter = iter->next)
+    {
+      GskGLTexture *other = iter->data;
+
+      if (other->height > texture->height ||
+          (other->height == texture->height &&
+           other->width > texture->width))
+        break;
+
+      sibling = iter;
+    }
+
+  g_queue_insert_after_link (&self->by_width, sibling, &texture->width_link);
+}
+
+GskGLTexture *
+gsk_gl_texture_pool_get (GskGLTexturePool *self,
+                         float             width,
+                         float             height,
+                         int               min_filter,
+                         int               mag_filter,
+                         gboolean          always_create)
+{
+  GskGLTexture *texture;
+
+  g_return_val_if_fail (self != NULL, NULL);
+
+  if (always_create)
+    goto create_texture;
+
+  if (width >= height)
+    {
+      for (GList *iter = self->by_width.head;
+           iter != NULL;
+           iter = iter->next)
+        {
+          texture = iter->data;
+
+          if (texture->width >= width &&
+              texture->height >= height &&
+              texture->min_filter == min_filter &&
+              texture->mag_filter == mag_filter)
+            {
+              g_queue_unlink (&self->by_width, &texture->width_link);
+              g_queue_unlink (&self->by_height, &texture->height_link);
+
+              return texture;
+            }
+        }
+    }
+  else
+    {
+      for (GList *iter = self->by_height.head;
+           iter != NULL;
+           iter = iter->next)
+        {
+          texture = iter->data;
+
+          if (texture->width >= width &&
+              texture->height >= height &&
+              texture->min_filter == min_filter &&
+              texture->mag_filter == mag_filter)
+            {
+              g_queue_unlink (&self->by_width, &texture->width_link);
+              g_queue_unlink (&self->by_height, &texture->height_link);
+
+              return texture;
+            }
+        }
+    }
+
+create_texture:
+
+  texture = g_slice_new0 (GskGLTexture);
+  texture->width_link.data = texture;
+  texture->height_link.data = texture;
+  texture->min_filter = min_filter;
+  texture->mag_filter = mag_filter;
+
+  glGenTextures (1, &texture->texture_id);
+
+  glActiveTexture (GL_TEXTURE0);
+  glBindTexture (GL_TEXTURE_2D, texture->texture_id);
+  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, min_filter);
+  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, mag_filter);
+  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+  if (gdk_gl_context_get_use_es (gdk_gl_context_get_current ()))
+    glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+  else
+    glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_BGRA, GL_UNSIGNED_BYTE, NULL);
+
+  glBindTexture (GL_TEXTURE_2D, 0);
+
+  return texture;
+}
diff --git a/gsk/next/gskgltexturepoolprivate.h b/gsk/next/gskgltexturepoolprivate.h
new file mode 100644
index 0000000000..ebedd6563d
--- /dev/null
+++ b/gsk/next/gskgltexturepoolprivate.h
@@ -0,0 +1,69 @@
+/* gskgltexturepoolprivate.h
+ *
+ * Copyright 2020 Christian Hergert <chergert redhat com>
+ *
+ * This file is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation; either version 2.1 of the License, or (at your option)
+ * any later version.
+ *
+ * This file is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+#ifndef _GSK_GL_TEXTURE_POOL_PRIVATE_H__
+#define _GSK_GL_TEXTURE_POOL_PRIVATE_H__
+
+#include "gskgltypes.h"
+
+G_BEGIN_DECLS
+
+typedef struct _GskGLTexture GskGLTexture;
+typedef struct _GskGLTexturePool GskGLTexturePool;
+
+struct _GskGLTexturePool
+{
+  GQueue by_width;
+  GQueue by_height;
+};
+
+struct _GskGLTexture
+{
+  GList       width_link;  /* Used to sort textures by width */
+  GList       height_link; /* Used to sort textures by height */
+
+  gint64      last_used_in_frame;
+
+  GdkTexture *user;
+
+  guint       texture_id;
+
+  float       width;
+  float       height;
+  int         min_filter;
+  int         mag_filter;
+
+  guint       permanent : 1;
+};
+
+void          gsk_gl_texture_pool_init  (GskGLTexturePool *self);
+void          gsk_gl_texture_pool_clear (GskGLTexturePool *self);
+GskGLTexture *gsk_gl_texture_pool_get   (GskGLTexturePool *self,
+                                         float             width,
+                                         float             height,
+                                         int               min_filter,
+                                         int               mag_filter,
+                                         gboolean          always_create);
+void          gsk_gl_texture_pool_put   (GskGLTexturePool *self,
+                                         GskGLTexture     *texture);
+
+G_END_DECLS
+
+#endif /* _GSK_GL_TEXTURE_POOL_PRIVATE_H__ */