path: root/mr1877.patch

Author: Daniel van Vugt <daniel.van.vugt@canonical.com>
Source: https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1877
Editor: Sung Mingi <FiestaLake@protonmail.com>
Commit: 463d746d30f66925657fea8711acd6cfa5ab01d7
Last Updated: 04/13/22 (Mutter 42.0+r45+g9d0f612de-2)
---

By avoiding StScrollViewFade we avoid offscreening and therefore
avoid painting everything twice to get it on screen. So this almost
halves the render time of the icon grid.

---
diff --git a/src/compositor/clutter-utils.c b/src/compositor/clutter-utils.c
index 86d788562e383c38961de1b385bb7bbf16424d28..3c7165f1ef1bb70f2fab58adb4d09716ef816e35 100644
--- a/src/compositor/clutter-utils.c
+++ b/src/compositor/clutter-utils.c
@@ -69,8 +69,7 @@ gboolean
 meta_actor_vertices_are_untransformed (graphene_point3d_t *verts,
                                        float               widthf,
                                        float               heightf,
-                                       int                *x_origin,
-                                       int                *y_origin)
+                                       MetaTransforms     *trans)
 {
   int width, height;
   int v0x, v0y, v1x, v1y, v2x, v2y, v3x, v3y;
@@ -90,6 +89,14 @@ meta_actor_vertices_are_untransformed (graphene_point3d_t *verts,
   x = v0x >> 8;
   y = v0y >> 8;
 
+  if (trans)
+    {
+      trans->x_origin = x;
+      trans->y_origin = y;
+      trans->x_scale = (v1x - v0x) / (float) width;
+      trans->y_scale = (v2y - v0y) / (float) height;
+    }
+
   /* At integral coordinates? */
   if (x * 256 != v0x || y * 256 != v0y)
     return FALSE;
@@ -103,11 +110,6 @@ meta_actor_vertices_are_untransformed (graphene_point3d_t *verts,
       v3x != v1x || v3y != v2y)
     return FALSE;
 
-  if (x_origin)
-    *x_origin = x;
-  if (y_origin)
-    *y_origin = y;
-
   return TRUE;
 }
 
@@ -137,8 +139,7 @@ meta_actor_painting_untransformed (CoglFramebuffer *fb,
                                    int              paint_height,
                                    int              sample_width,
                                    int              sample_height,
-                                   int             *x_origin,
-                                   int             *y_origin)
+                                   MetaTransforms  *trans)
 {
   graphene_matrix_t modelview, projection, modelview_projection;
   graphene_point3d_t vertices[4];
@@ -183,6 +184,6 @@ meta_actor_painting_untransformed (CoglFramebuffer *fb,
 
   return meta_actor_vertices_are_untransformed (vertices,
                                                 sample_width, sample_height,
-                                                x_origin, y_origin);
+                                                trans);
 }
 
diff --git a/src/compositor/clutter-utils.h b/src/compositor/clutter-utils.h
index 8ed0e2a4d127d037a0371d01d1d7dbd349adc161..039e61a61998dba8acff584017daf258fe763f18 100644
--- a/src/compositor/clutter-utils.h
+++ b/src/compositor/clutter-utils.h
@@ -23,18 +23,21 @@
 
 #include "clutter/clutter.h"
 
+typedef struct {
+  int x_origin, y_origin;
+  float x_scale, y_scale;
+} MetaTransforms;
+
 gboolean meta_actor_vertices_are_untransformed (graphene_point3d_t *verts,
                                                 float               widthf,
                                                 float               heightf,
-                                                int                *x_origin,
-                                                int                *y_origin);
+                                                MetaTransforms     *trans);
 
 gboolean meta_actor_painting_untransformed (CoglFramebuffer *fb,
                                             int              paint_width,
                                             int              paint_height,
                                             int              sample_widthf,
                                             int              sample_heightf,
-                                            int             *x_origin,
-                                            int             *y_origin);
+                                            MetaTransforms  *trans);
 
 #endif /* __META_CLUTTER_UTILS_H__ */
diff --git a/src/compositor/meta-background-content.c b/src/compositor/meta-background-content.c
index 49f5885ca70d1a69ee81be4139f448fcb7c70dce..93de521d05bb7a334fbccfc872d220a43ca7d7da 100644
--- a/src/compositor/meta-background-content.c
+++ b/src/compositor/meta-background-content.c
@@ -561,7 +561,7 @@ setup_pipeline (MetaBackgroundContent *self,
                                          actor_pixel_rect->height,
                                          self->texture_width,
                                          self->texture_height,
-                                         NULL, NULL))
+                                         NULL))
     {
       min_filter = COGL_PIPELINE_FILTER_NEAREST;
       mag_filter = COGL_PIPELINE_FILTER_NEAREST;
diff --git a/src/compositor/meta-cullable.c b/src/compositor/meta-cullable.c
index 6f38c5e47c8f8e219bd195fc2da274c97ba298ec..e306c56e287752ab9e09ec3958e205de3a4d47a9 100644
--- a/src/compositor/meta-cullable.c
+++ b/src/compositor/meta-cullable.c
@@ -175,7 +175,7 @@ meta_cullable_default_is_untransformed (MetaCullable *cullable)
   clutter_actor_get_abs_allocation_vertices (CLUTTER_ACTOR (cullable), verts);
 
   return meta_actor_vertices_are_untransformed (verts, width, height,
-                                                NULL, NULL);
+                                                NULL);
 }
 
 static void
diff --git a/src/compositor/meta-shaped-texture.c b/src/compositor/meta-shaped-texture.c
index 34fec6852ad8dd348934e16474e97265a7f390d8..222095587a3f258721e69d647459c8af85fd4946 100644
--- a/src/compositor/meta-shaped-texture.c
+++ b/src/compositor/meta-shaped-texture.c
@@ -41,7 +41,6 @@
 
 #include "cogl/cogl.h"
 #include "compositor/clutter-utils.h"
-#include "compositor/meta-texture-tower.h"
 #include "compositor/region-utils.h"
 #include "core/boxes-private.h"
 #include "meta/meta-shaped-texture.h"
@@ -82,8 +81,6 @@ struct _MetaShapedTexture
 {
   GObject parent;
 
-  MetaTextureTower *paint_tower;
-
   CoglTexture *texture;
   CoglTexture *mask_texture;
   CoglSnippet *snippet;
@@ -96,6 +93,11 @@ struct _MetaShapedTexture
   CoglPipeline *unblended_pipeline;
   CoglPipeline *unblended_tower_pipeline;
 
+  CoglTexture *mipmap_texture;
+  gboolean mipmap_texture_out_of_date;
+  CoglFramebuffer *mipmap_fb;
+  CoglPipeline *mipmap_pipeline;
+
   gboolean is_y_inverted;
 
   /* The region containing only fully opaque pixels */
@@ -154,8 +156,6 @@ invalidate_size (MetaShapedTexture *stex)
 static void
 meta_shaped_texture_init (MetaShapedTexture *stex)
 {
-  stex->paint_tower = meta_texture_tower_new ();
-
   stex->buffer_scale = 1;
   stex->texture = NULL;
   stex->mask_texture = NULL;
@@ -252,6 +252,13 @@ meta_shaped_texture_reset_pipelines (MetaShapedTexture *stex)
   g_clear_pointer (&stex->unblended_tower_pipeline, cogl_object_unref);
 }
 
+static void
+free_mipmaps (MetaShapedTexture *stex)
+{
+  g_clear_object (&stex->mipmap_fb);
+  cogl_clear_object (&stex->mipmap_texture);
+}
+
 static void
 meta_shaped_texture_dispose (GObject *object)
 {
@@ -259,9 +266,8 @@ meta_shaped_texture_dispose (GObject *object)
 
   g_clear_handle_id (&stex->remipmap_timeout_id, g_source_remove);
 
-  if (stex->paint_tower)
-    meta_texture_tower_free (stex->paint_tower);
-  stex->paint_tower = NULL;
+  free_mipmaps (stex);
+  cogl_clear_object (&stex->mipmap_pipeline);
 
   g_clear_pointer (&stex->texture, cogl_object_unref);
 
@@ -618,13 +624,7 @@ set_cogl_texture (MetaShapedTexture *stex,
       update_size (stex);
     }
 
-  /* NB: We don't queue a redraw of the actor here because we don't
-   * know how much of the buffer has changed with respect to the
-   * previous buffer. We only queue a redraw in response to surface
-   * damage. */
-
-  if (stex->create_mipmaps)
-    meta_texture_tower_set_base_texture (stex->paint_tower, cogl_tex);
+  stex->mipmap_texture_out_of_date = TRUE;
 }
 
 static gboolean
@@ -652,11 +652,14 @@ flip_ints (int *x,
   *y = tmp;
 }
 
+static CoglTexture *
+select_texture_for_paint (MetaShapedTexture   *stex,
+                          ClutterPaintContext *paint_context);
+
 static void
 do_paint_content (MetaShapedTexture   *stex,
                   ClutterPaintNode    *root_node,
                   ClutterPaintContext *paint_context,
-                  CoglTexture         *paint_tex,
                   ClutterActorBox     *alloc,
                   uint8_t              opacity)
 {
@@ -665,7 +668,9 @@ do_paint_content (MetaShapedTexture   *stex,
   gboolean use_opaque_region;
   cairo_region_t *blended_tex_region;
   CoglContext *ctx;
-  CoglPipelineFilter filter;
+  CoglPipelineFilter min_filter, mag_filter;
+  MetaTransforms transforms;
+  CoglTexture *paint_tex = stex->texture;
   CoglFramebuffer *framebuffer;
   int sample_width, sample_height;
   gboolean debug_paint_opaque_region;
@@ -712,10 +717,33 @@ do_paint_content (MetaShapedTexture   *stex,
   if (meta_actor_painting_untransformed (framebuffer,
                                          dst_width, dst_height,
                                          sample_width, sample_height,
-                                         NULL, NULL))
-    filter = COGL_PIPELINE_FILTER_NEAREST;
+                                         &transforms))
+    {
+      min_filter = COGL_PIPELINE_FILTER_NEAREST;
+      mag_filter = COGL_PIPELINE_FILTER_NEAREST;
+
+      /* Back to normal desktop viewing. Save some memory */
+      free_mipmaps (stex);
+    }
   else
-    filter = COGL_PIPELINE_FILTER_LINEAR;
+    {
+      min_filter = COGL_PIPELINE_FILTER_LINEAR;
+      mag_filter = COGL_PIPELINE_FILTER_LINEAR;
+
+      /* If we're painting a texture below half its native resolution
+       * then mipmapping is required to avoid aliasing. If it's above
+       * half then sticking with COGL_PIPELINE_FILTER_LINEAR will look
+       * and perform better.
+       */
+      if (stex->create_mipmaps &&
+          transforms.x_scale < 0.5 &&
+          transforms.y_scale < 0.5)
+        {
+          paint_tex = select_texture_for_paint (stex, paint_context);
+          if (paint_tex == stex->mipmap_texture)
+            min_filter = COGL_PIPELINE_FILTER_LINEAR_MIPMAP_NEAREST;
+        }
+    }
 
   ctx = clutter_backend_get_cogl_context (clutter_get_default_backend ());
 
@@ -777,7 +805,7 @@ do_paint_content (MetaShapedTexture   *stex,
 
           opaque_pipeline = get_unblended_pipeline (stex, ctx, paint_tex);
           cogl_pipeline_set_layer_texture (opaque_pipeline, 0, paint_tex);
-          cogl_pipeline_set_layer_filters (opaque_pipeline, 0, filter, filter);
+          cogl_pipeline_set_layer_filters (opaque_pipeline, 0, min_filter, mag_filter);
 
           n_rects = cairo_region_num_rectangles (region);
           for (i = 0; i < n_rects; i++)
@@ -825,11 +853,11 @@ do_paint_content (MetaShapedTexture   *stex,
         {
           blended_pipeline = get_masked_pipeline (stex, ctx, paint_tex);
           cogl_pipeline_set_layer_texture (blended_pipeline, 1, stex->mask_texture);
-          cogl_pipeline_set_layer_filters (blended_pipeline, 1, filter, filter);
+          cogl_pipeline_set_layer_filters (blended_pipeline, 1, min_filter, mag_filter);
         }
 
       cogl_pipeline_set_layer_texture (blended_pipeline, 0, paint_tex);
-      cogl_pipeline_set_layer_filters (blended_pipeline, 0, filter, filter);
+      cogl_pipeline_set_layer_filters (blended_pipeline, 0, min_filter, mag_filter);
 
       CoglColor color;
       cogl_color_init_from_4ub (&color, opacity, opacity, opacity, opacity);
@@ -894,6 +922,94 @@ do_paint_content (MetaShapedTexture   *stex,
   g_clear_pointer (&blended_tex_region, cairo_region_destroy);
 }
 
+static void
+ensure_mipmap_texture (MetaShapedTexture *stex)
+{
+  CoglContext *ctx =
+    clutter_backend_get_cogl_context (clutter_get_default_backend ());
+  int width, height;
+
+  /* Let's avoid spending any texture memory copying the base level texture
+   * because we'll never need that one and it would have used most of the
+   * memory;
+   *    S(0) = W x H
+   *    S(n) = S(n-1) / 4
+   *    sum to infinity of S(n) = 4/3 * S(0)
+   * So subtracting S(0) means even infinite mipmap levels only need one third
+   * of the original texture's memory. Finite levels need less.
+   *
+   * The fact that mipmap level 0 of stex->mipmap_texture is half the
+   * resolution of stex->texture makes no visual difference, so long as you're
+   * never trying to view a level of detail higher than half. If you need that
+   * then just use stex->texture instead of stex->mipmap_texture, which is
+   * faster anyway.
+   */
+  width = cogl_texture_get_width (stex->texture) / 2;
+  height = cogl_texture_get_height (stex->texture) / 2;
+
+  if (!width || !height)
+    {
+      free_mipmaps (stex);
+      return;
+    }
+
+  if (!stex->mipmap_texture ||
+      cogl_texture_get_width (stex->mipmap_texture) != width ||
+      cogl_texture_get_height (stex->mipmap_texture) != height)
+    {
+      CoglOffscreen *offscreen;
+      CoglTexture2D *tex2d;
+
+      free_mipmaps (stex);
+
+      tex2d = cogl_texture_2d_new_with_size (ctx, width, height);
+      if (!tex2d)
+        return;
+
+      stex->mipmap_texture = COGL_TEXTURE (tex2d);
+
+      offscreen = cogl_offscreen_new_with_texture (stex->mipmap_texture);
+      if (!offscreen)
+        {
+          free_mipmaps (stex);
+          return;
+        }
+
+      stex->mipmap_fb = COGL_FRAMEBUFFER (offscreen);
+
+      if (!cogl_framebuffer_allocate (stex->mipmap_fb, NULL))
+        {
+          free_mipmaps (stex);
+          return;
+        }
+
+      cogl_framebuffer_orthographic (stex->mipmap_fb,
+                                     0, 0, width, height, -1.0, 1.0);
+
+      stex->mipmap_texture_out_of_date = TRUE;
+    }
+
+  if (stex->mipmap_texture_out_of_date)
+    {
+      if (!stex->mipmap_pipeline)
+        {
+          stex->mipmap_pipeline = cogl_pipeline_new (ctx);
+          cogl_pipeline_set_blend (stex->mipmap_pipeline, "RGBA = ADD (SRC_COLOR, 0)", NULL);
+          cogl_pipeline_set_layer_filters (stex->mipmap_pipeline, 0,
+                                           COGL_PIPELINE_FILTER_LINEAR,
+                                           COGL_PIPELINE_FILTER_LINEAR);
+        }
+
+      cogl_pipeline_set_layer_texture (stex->mipmap_pipeline, 0, stex->texture);
+      cogl_framebuffer_draw_textured_rectangle (stex->mipmap_fb,
+                                                stex->mipmap_pipeline,
+                                                0, 0, width, height,
+                                                0.0, 0.0, 1.0, 1.0);
+
+      stex->mipmap_texture_out_of_date = FALSE;
+    }
+}
+
 static CoglTexture *
 select_texture_for_paint (MetaShapedTexture   *stex,
                           ClutterPaintContext *paint_context)
@@ -913,8 +1029,8 @@ select_texture_for_paint (MetaShapedTexture   *stex,
       if (age >= MIN_MIPMAP_AGE_USEC ||
           stex->fast_updates < MIN_FAST_UPDATES_BEFORE_UNMIPMAP)
         {
-          texture = meta_texture_tower_get_paint_texture (stex->paint_tower,
-                                                          paint_context);
+          ensure_mipmap_texture (stex);
+          texture = stex->mipmap_texture;
         }
     }
 
@@ -946,7 +1062,6 @@ meta_shaped_texture_paint_content (ClutterContent      *content,
 {
   MetaShapedTexture *stex = META_SHAPED_TEXTURE (content);
   ClutterActorBox alloc;
-  CoglTexture *paint_tex = NULL;
   uint8_t opacity;
 
   if (stex->clip_region && cairo_region_is_empty (stex->clip_region))
@@ -967,14 +1082,13 @@ meta_shaped_texture_paint_content (ClutterContent      *content,
    * Setting the texture quality to high without SGIS_generate_mipmap
    * support for TFP textures will result in fallbacks to XGetImage.
    */
-  paint_tex = select_texture_for_paint (stex, paint_context);
-  if (!paint_tex)
+  if (stex->texture == NULL)
     return;
 
   opacity = clutter_actor_get_paint_opacity (actor);
   clutter_actor_get_content_box (actor, &alloc);
 
-  do_paint_content (stex, root_node, paint_context, paint_tex, &alloc, opacity);
+  do_paint_content (stex, root_node, paint_context, &alloc, opacity);
 }
 
 static gboolean
@@ -1012,10 +1126,10 @@ meta_shaped_texture_set_create_mipmaps (MetaShapedTexture *stex,
 
   if (create_mipmaps != stex->create_mipmaps)
     {
-      CoglTexture *base_texture;
       stex->create_mipmaps = create_mipmaps;
-      base_texture = create_mipmaps ? stex->texture : NULL;
-      meta_texture_tower_set_base_texture (stex->paint_tower, base_texture);
+
+      if (!stex->create_mipmaps)
+        free_mipmaps (stex);
     }
 }
 
@@ -1144,12 +1258,7 @@ meta_shaped_texture_update_area (MetaShapedTexture     *stex,
                                      clip);
     }
 
-  meta_texture_tower_update_area (stex->paint_tower,
-                                  x,
-                                  y,
-                                  width,
-                                  height);
-
+  stex->mipmap_texture_out_of_date = TRUE;
   stex->prev_invalidation = stex->last_invalidation;
   stex->last_invalidation = g_get_monotonic_time ();
 
@@ -1214,8 +1323,6 @@ meta_shaped_texture_set_snippet (MetaShapedTexture *stex,
   g_clear_pointer (&stex->snippet, cogl_object_unref);
   if (snippet)
     stex->snippet = cogl_object_ref (snippet);
-
-  meta_texture_tower_set_snippet (stex->paint_tower, snippet);
 }
 
 /**
diff --git a/src/compositor/meta-surface-actor.c b/src/compositor/meta-surface-actor.c
index c2bf6696a2092882215da37ef865ddaeb79bf5e4..fcd94b86d3a3e3e0df6923095196a9ee3c4a5e6c 100644
--- a/src/compositor/meta-surface-actor.c
+++ b/src/compositor/meta-surface-actor.c
@@ -331,7 +331,7 @@ meta_surface_actor_is_untransformed (MetaCullable *cullable)
   return meta_actor_vertices_are_untransformed (verts,
                                                 width * geometry_scale,
                                                 height * geometry_scale,
-                                                NULL, NULL);
+                                                NULL);
 }
 
 static void
diff --git a/src/compositor/meta-texture-tower.c b/src/compositor/meta-texture-tower.c
deleted file mode 100644
index 510e85f7968eb09edaace5479a0ac9d43f4d9728..0000000000000000000000000000000000000000
--- a/src/compositor/meta-texture-tower.c
+++ /dev/null
@@ -1,513 +0,0 @@
-/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
-/*
- * MetaTextureTower
- *
- * Mipmap emulation by creation of scaled down images
- *
- * Copyright (C) 2009 Red Hat, Inc.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * This program 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
- * 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/>.
- */
-
-#include "config.h"
-
-#include <math.h>
-#include <string.h>
-
-#include "compositor/meta-texture-tower.h"
-
-#ifndef M_LOG2E
-#define M_LOG2E 1.4426950408889634074
-#endif
-
-#define MAX_TEXTURE_LEVELS 12
-
-/* If the texture format in memory doesn't match this, then Mesa
- * will do the conversion, so things will still work, but it might
- * be slow depending on how efficient Mesa is. These should be the
- * native formats unless the display is 16bpp. If conversions
- * here are a bottleneck, investigate whether we are converting when
- * storing window data *into* the texture before adding extra code
- * to handle multiple texture formats.
- */
-#if G_BYTE_ORDER == G_LITTLE_ENDIAN
-#define TEXTURE_FORMAT COGL_PIXEL_FORMAT_BGRA_8888_PRE
-#else
-#define TEXTURE_FORMAT COGL_PIXEL_FORMAT_ARGB_8888_PRE
-#endif
-
-typedef struct
-{
-  guint16 x1;
-  guint16 y1;
-  guint16 x2;
-  guint16 y2;
-} Box;
-
-struct _MetaTextureTower
-{
-  int n_levels;
-  CoglTexture *textures[MAX_TEXTURE_LEVELS];
-  CoglOffscreen *fbos[MAX_TEXTURE_LEVELS];
-  Box invalid[MAX_TEXTURE_LEVELS];
-  CoglPipeline *pipeline_template;
-  CoglSnippet *snippet;
-};
-
-/**
- * meta_texture_tower_new:
- *
- * Creates a new texture tower. The base texture has to be set with
- * meta_texture_tower_set_base_texture() before use.
- *
- * Return value: the new texture tower. Free with meta_texture_tower_free()
- */
-MetaTextureTower *
-meta_texture_tower_new (void)
-{
-  MetaTextureTower *tower;
-
-  tower = g_new0 (MetaTextureTower, 1);
-
-  return tower;
-}
-
-/**
- * meta_texture_tower_free:
- * @tower: a #MetaTextureTower
- *
- * Frees a texture tower created with meta_texture_tower_new().
- */
-void
-meta_texture_tower_free (MetaTextureTower *tower)
-{
-  g_return_if_fail (tower != NULL);
-
-  if (tower->pipeline_template != NULL)
-    cogl_object_unref (tower->pipeline_template);
-
-  meta_texture_tower_set_base_texture (tower, NULL);
-  cogl_clear_object (&tower->snippet);
-
-  g_free (tower);
-}
-
-/**
- * meta_texture_tower_set_base_texture:
- * @tower: a #MetaTextureTower
- * @texture: the new texture used as a base for scaled down versions
- *
- * Sets the base texture that is the scaled texture that the
- * scaled textures of the tower are derived from. The texture itself
- * will be used as level 0 of the tower and will be referenced until
- * unset or until the tower is freed.
- */
-void
-meta_texture_tower_set_base_texture (MetaTextureTower *tower,
-                                     CoglTexture      *texture)
-{
-  int i;
-
-  g_return_if_fail (tower != NULL);
-
-  if (texture == tower->textures[0])
-    return;
-
-  if (tower->textures[0] != NULL)
-    {
-      for (i = 1; i < tower->n_levels; i++)
-        {
-          cogl_clear_object (&tower->textures[i]);
-          g_clear_object (&tower->fbos[i]);
-        }
-
-      cogl_object_unref (tower->textures[0]);
-    }
-
-  tower->textures[0] = texture;
-
-  if (tower->textures[0] != NULL)
-    {
-      int width, height;
-
-      cogl_object_ref (tower->textures[0]);
-
-      width = cogl_texture_get_width (tower->textures[0]);
-      height = cogl_texture_get_height (tower->textures[0]);
-
-      tower->n_levels = 1 + MAX ((int)(M_LOG2E * log (width)), (int)(M_LOG2E * log (height)));
-      tower->n_levels = MIN (tower->n_levels, MAX_TEXTURE_LEVELS);
-
-      meta_texture_tower_update_area (tower, 0, 0, width, height);
-    }
-  else
-    {
-      tower->n_levels = 0;
-    }
-}
-
-/**
- * meta_texture_tower_update_area:
- * @tower: a #MetaTextureTower
- * @x: X coordinate of upper left of rectangle that changed
- * @y: Y coordinate of upper left of rectangle that changed
- * @width: width of rectangle that changed
- * @height: height rectangle that changed
- *
- * Mark a region of the base texture as having changed; the next
- * time a scaled down version of the base texture is retrieved,
- * the appropriate area of the scaled down texture will be updated.
- */
-void
-meta_texture_tower_update_area (MetaTextureTower *tower,
-                                int               x,
-                                int               y,
-                                int               width,
-                                int               height)
-{
-  int texture_width, texture_height;
-  Box invalid;
-  int i;
-
-  g_return_if_fail (tower != NULL);
-
-  if (tower->textures[0] == NULL)
-    return;
-
-  texture_width = cogl_texture_get_width (tower->textures[0]);
-  texture_height = cogl_texture_get_height (tower->textures[0]);
-
-  invalid.x1 = x;
-  invalid.y1 = y;
-  invalid.x2 = x + width;
-  invalid.y2 = y + height;
-
-  for (i = 1; i < tower->n_levels; i++)
-    {
-      texture_width = MAX (1, texture_width / 2);
-      texture_height = MAX (1, texture_height / 2);
-
-      invalid.x1 = invalid.x1 / 2;
-      invalid.y1 = invalid.y1 / 2;
-      invalid.x2 = MIN (texture_width, (invalid.x2 + 1) / 2);
-      invalid.y2 = MIN (texture_height, (invalid.y2 + 1) / 2);
-
-      if (tower->invalid[i].x1 == tower->invalid[i].x2 ||
-          tower->invalid[i].y1 == tower->invalid[i].y2)
-        {
-          tower->invalid[i] = invalid;
-        }
-      else
-        {
-          tower->invalid[i].x1 = MIN (tower->invalid[i].x1, invalid.x1);
-          tower->invalid[i].y1 = MIN (tower->invalid[i].y1, invalid.y1);
-          tower->invalid[i].x2 = MAX (tower->invalid[i].x2, invalid.x2);
-          tower->invalid[i].y2 = MAX (tower->invalid[i].y2, invalid.y2);
-        }
-    }
-}
-
-void
-meta_texture_tower_set_snippet (MetaTextureTower *tower,
-                                CoglSnippet      *snippet)
-{
-  int i;
-
-  if (tower->snippet == snippet)
-    return;
-
-  g_clear_pointer (&tower->snippet, cogl_object_unref);
-
-  if (snippet)
-    tower->snippet = cogl_object_ref (snippet);
-
-  for (i = 1; i < tower->n_levels; i++)
-    {
-      cogl_clear_object (&tower->textures[i]);
-      g_clear_object (&tower->fbos[i]);
-    }
-  cogl_clear_object (&tower->pipeline_template);
-}
-
-/* It generally looks worse if we scale up a window texture by even a
- * small amount than if we scale it down using bilinear filtering, so
- * we always pick the *larger* adjacent level. */
-#define LOD_BIAS (-0.49)
-
-/* This determines the appropriate level of detail to use when drawing the
- * texture, in a way that corresponds to what the GL specification does
- * when mip-mapping. This is probably fancier and slower than what we need,
- * but we do the computation only once each time we paint a window, and
- * its easier to just use the equations from the specification than to
- * come up with something simpler.
- *
- * If window is being painted at an angle from the viewer, then we have to
- * pick a point in the texture; we use the middle of the texture (which is
- * why the width/height are passed in.) This is not the normal case for
- * Meta.
- */
-static int
-get_paint_level (ClutterPaintContext *paint_context,
-                 int                  width,
-                 int                  height)
-{
-  CoglFramebuffer *framebuffer;
-  graphene_matrix_t projection, modelview, pm;
-  float xx, xy, xw;
-  float yx, yy, yw;
-  float wx, wy, ww;
-  float v[4];
-  double viewport_width, viewport_height;
-  double u0, v0;
-  double xc, yc, wc;
-  double dxdu_, dxdv_, dydu_, dydv_;
-  double det_, det_sq;
-  double rho_sq;
-  double lambda;
-
-  /* See
-   * http://www.opengl.org/registry/doc/glspec32.core.20090803.pdf
-   * Section 3.8.9, p. 1.6.2. Here we have
-   *
-   *  u(x,y) = x_o;
-   *  v(x,y) = y_o;
-   *
-   * Since we are mapping 1:1 from object coordinates into pixel
-   * texture coordinates, the clip coordinates are:
-   *
-   *  (x_c)                               (x_o)        (u)
-   *  (y_c) = (M_projection)(M_modelview) (y_o) = (PM) (v)
-   *  (z_c)                               (z_o)        (0)
-   *  (w_c)                               (w_o)        (1)
-   */
-
-  framebuffer = clutter_paint_context_get_framebuffer (paint_context);
-  cogl_framebuffer_get_projection_matrix (framebuffer, &projection);
-  cogl_framebuffer_get_modelview_matrix (framebuffer, &modelview);
-
-  graphene_matrix_multiply (&modelview, &projection, &pm);
-
-  xx = graphene_matrix_get_value (&pm, 0, 0);
-  xy = graphene_matrix_get_value (&pm, 0, 1);
-  xw = graphene_matrix_get_value (&pm, 0, 3);
-  yx = graphene_matrix_get_value (&pm, 1, 0);
-  yy = graphene_matrix_get_value (&pm, 1, 1);
-  yw = graphene_matrix_get_value (&pm, 1, 3);
-  wx = graphene_matrix_get_value (&pm, 3, 0);
-  wy = graphene_matrix_get_value (&pm, 3, 1);
-  ww = graphene_matrix_get_value (&pm, 3, 3);
-
-  cogl_framebuffer_get_viewport4fv (framebuffer, v);
-  viewport_width = v[2];
-  viewport_height = v[3];
-
-  u0 = width / 2.;
-  v0 = height / 2.;
-
-  xc = xx * u0 + yx * v0 + wx;
-  yc = xy * u0 + yy * v0 + wy;
-  wc = xw * u0 + yw * v0 + ww;
-
-  /* We'll simplify the equations below for a bit of micro-optimization.
-   * The commented out code is the unsimplified version.
-
-  // Partial derivates of window coordinates:
-  //
-  //  x_w = 0.5 * viewport_width * x_c / w_c + viewport_center_x
-  //  y_w = 0.5 * viewport_height * y_c / w_c + viewport_center_y
-  //
-  // with respect to u, v, using
-  // d(a/b)/dx = da/dx * (1/b) - a * db/dx / (b^2)
-
-  dxdu = 0.5 * viewport_width * (xx - xw * (xc/wc)) / wc;
-  dxdv = 0.5 * viewport_width * (yx - yw * (xc/wc)) / wc;
-  dydu = 0.5 * viewport_height * (xy - xw * (yc/wc)) / wc;
-  dydv = 0.5 * viewport_height * (yy - yw * (yc/wc)) / wc;
-
-  // Compute the inverse partials as the matrix inverse
-  det = dxdu * dydv - dxdv * dydu;
-
-  dudx =   dydv / det;
-  dudy = - dxdv / det;
-  dvdx = - dydu / det;
-  dvdy =   dvdu / det;
-
-  // Scale factor; maximum of the distance in texels for a change of 1 pixel
-  // in the X direction or 1 pixel in the Y direction
-  rho = MAX (sqrt (dudx * dudx + dvdx * dvdx), sqrt(dudy * dudy + dvdy * dvdy));
-
-  // Level of detail
-  lambda = log2 (rho) + LOD_BIAS;
-  */
-
-  /* dxdu * wc, etc */
-  dxdu_ = 0.5 * viewport_width * (xx - xw * (xc/wc));
-  dxdv_ = 0.5 * viewport_width * (yx - yw * (xc/wc));
-  dydu_ = 0.5 * viewport_height * (xy - xw * (yc/wc));
-  dydv_ = 0.5 * viewport_height * (yy - yw * (yc/wc));
-
-  /* det * wc^2 */
-  det_ = dxdu_ * dydv_ - dxdv_ * dydu_;
-  det_sq = det_ * det_;
-  if (det_sq == 0.0)
-    return -1;
-
-  /* (rho * det * wc)^2 */
-  rho_sq = MAX (dydv_ * dydv_ + dydu_ * dydu_, dxdv_ * dxdv_ + dxdu_ * dxdu_);
-  lambda = 0.5 * M_LOG2E * log (rho_sq * wc * wc / det_sq) + LOD_BIAS;
-
-#if 0
-  g_print ("%g %g %g\n", 0.5 * viewport_width * xx / ww, 0.5 * viewport_height * yy / ww, lambda);
-#endif
-
-  if (lambda <= 0.)
-    return 0;
-  else
-    return (int)(0.5 + lambda);
-}
-
-static void
-texture_tower_create_texture (MetaTextureTower *tower,
-                              int               level,
-                              int               width,
-                              int               height)
-{
-  CoglContext *ctx =
-    clutter_backend_get_cogl_context (clutter_get_default_backend ());
-
-  tower->textures[level] =
-    COGL_TEXTURE (cogl_texture_2d_new_with_size (ctx, width, height));
-
-  tower->invalid[level].x1 = 0;
-  tower->invalid[level].y1 = 0;
-  tower->invalid[level].x2 = width;
-  tower->invalid[level].y2 = height;
-}
-
-static void
-texture_tower_revalidate (MetaTextureTower *tower,
-                          int               level)
-{
-  CoglTexture *source_texture = tower->textures[level - 1];
-  int source_texture_width = cogl_texture_get_width (source_texture);
-  int source_texture_height = cogl_texture_get_height (source_texture);
-  CoglTexture *dest_texture = tower->textures[level];
-  int dest_texture_width = cogl_texture_get_width (dest_texture);
-  int dest_texture_height = cogl_texture_get_height (dest_texture);
-  Box *invalid = &tower->invalid[level];
-  CoglFramebuffer *fb;
-  GError *catch_error = NULL;
-  CoglPipeline *pipeline;
-
-  if (tower->fbos[level] == NULL)
-    tower->fbos[level] = cogl_offscreen_new_with_texture (dest_texture);
-
-  fb = COGL_FRAMEBUFFER (tower->fbos[level]);
-
-  if (!cogl_framebuffer_allocate (fb, &catch_error))
-    {
-      g_error_free (catch_error);
-      return;
-    }
-
-  cogl_framebuffer_orthographic (fb, 0, 0, dest_texture_width, dest_texture_height, -1., 1.);
-
-  if (!tower->pipeline_template)
-    {
-      CoglContext *ctx =
-        clutter_backend_get_cogl_context (clutter_get_default_backend ());
-      tower->pipeline_template = cogl_pipeline_new (ctx);
-      cogl_pipeline_set_blend (tower->pipeline_template, "RGBA = ADD (SRC_COLOR, 0)", NULL);
-    }
-
-  pipeline = cogl_pipeline_copy (tower->pipeline_template);
-  cogl_pipeline_set_layer_texture (pipeline, 0, tower->textures[level - 1]);
-
-  if (tower->snippet && level == 1)
-    cogl_pipeline_add_layer_snippet (pipeline, 0, tower->snippet);
-
-  cogl_framebuffer_draw_textured_rectangle (fb, pipeline,
-                                            invalid->x1, invalid->y1,
-                                            invalid->x2, invalid->y2,
-                                            (2. * invalid->x1) / source_texture_width,
-                                            (2. * invalid->y1) / source_texture_height,
-                                            (2. * invalid->x2) / source_texture_width,
-                                            (2. * invalid->y2) / source_texture_height);
-
-  cogl_object_unref (pipeline);
-
-  tower->invalid[level].x1 = tower->invalid[level].x2 = 0;
-  tower->invalid[level].y1 = tower->invalid[level].y2 = 0;
-}
-
-/**
- * meta_texture_tower_get_paint_texture:
- * @tower: a #MetaTextureTower
- * @paint_context: a #ClutterPaintContext
- *
- * Gets the texture from the tower that best matches the current
- * rendering scale. (On the assumption here the texture is going to
- * be rendered with vertex coordinates that correspond to its
- * size in pixels, so a 200x200 texture will be rendered on the
- * rectangle (0, 0, 200, 200).
- *
- * Return value: the COGL texture handle to use for painting, or
- *  %NULL if no base texture has yet been set.
- */
-CoglTexture *
-meta_texture_tower_get_paint_texture (MetaTextureTower    *tower,
-                                      ClutterPaintContext *paint_context)
-{
-  int texture_width, texture_height;
-  int level;
-
-  g_return_val_if_fail (tower != NULL, NULL);
-
-  if (tower->textures[0] == NULL)
-    return NULL;
-
-  texture_width = cogl_texture_get_width (tower->textures[0]);
-  texture_height = cogl_texture_get_height (tower->textures[0]);
-
-  level = get_paint_level (paint_context, texture_width, texture_height);
-  if (level < 0) /* singular paint matrix, scaled to nothing */
-    return NULL;
-  level = MIN (level, tower->n_levels - 1);
-
-  if (tower->textures[level] == NULL ||
-      (tower->invalid[level].x2 != tower->invalid[level].x1 &&
-       tower->invalid[level].y2 != tower->invalid[level].y1))
-    {
-      int i;
-
-      for (i = 1; i <= level; i++)
-        {
-          /* Use "floor" convention here to be consistent with the NPOT texture extension */
-          texture_width = MAX (1, texture_width / 2);
-          texture_height = MAX (1, texture_height / 2);
-
-          if (tower->textures[i] == NULL)
-            texture_tower_create_texture (tower, i, texture_width, texture_height);
-        }
-
-      for (i = 1; i <= level; i++)
-        {
-          if (tower->invalid[level].x2 != tower->invalid[level].x1 &&
-              tower->invalid[level].y2 != tower->invalid[level].y1)
-            texture_tower_revalidate (tower, i);
-        }
-    }
-
-  return tower->textures[level];
-}
diff --git a/src/compositor/meta-texture-tower.h b/src/compositor/meta-texture-tower.h
deleted file mode 100644
index 5522dfbb16ac9b207e979065413ac3c06f1ac974..0000000000000000000000000000000000000000
--- a/src/compositor/meta-texture-tower.h
+++ /dev/null
@@ -1,71 +0,0 @@
-/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
-/*
- * MetaTextureTower
- *
- * Mipmap emulation by creation of scaled down images
- *
- * Copyright (C) 2009 Red Hat, Inc.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * This program 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
- * 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/>.
- */
-
-#ifndef __META_TEXTURE_TOWER_H__
-#define __META_TEXTURE_TOWER_H__
-
-#include "clutter/clutter.h"
-
-G_BEGIN_DECLS
-
-/**
- * SECTION:MetaTextureTower
- * @short_description: mipmap emulation by creation of scaled down images
- *
- * A #MetaTextureTower is used to get good looking scaled down images when
- * we can't use the GL drivers mipmap support. There are two separate reasons
- *
- *  - Some cards (including radeon cards <= r5xx) only support
- *    TEXTURE_RECTANGLE_ARB and not NPOT textures. Rectangular textures
- *    are defined not to support mipmapping.
- *  - Even when NPOT textures are available, the combination of NPOT
- *    textures, texture_from_pixmap, and mipmapping doesn't typically
- *    work, since the X server doesn't allocate pixmaps in the right
- *    layout for mipmapping.
- *
- * So, what we do is create the "mipmap" levels ourselves by successive
- * power-of-two scaledowns, and when rendering pick the single texture
- * that best matches the scale we are rendering at. (Since we aren't
- * typically using perspective transforms, we'll frequently have a single
- * scale for the entire texture.)
- */
-
-typedef struct _MetaTextureTower MetaTextureTower;
-
-MetaTextureTower *meta_texture_tower_new               (void);
-void              meta_texture_tower_free              (MetaTextureTower *tower);
-void              meta_texture_tower_set_base_texture  (MetaTextureTower *tower,
-                                                        CoglTexture      *texture);
-void              meta_texture_tower_update_area       (MetaTextureTower *tower,
-                                                        int               x,
-                                                        int               y,
-                                                        int               width,
-                                                        int               height);
-CoglTexture      *meta_texture_tower_get_paint_texture (MetaTextureTower    *tower,
-                                                        ClutterPaintContext *paint_context);
-
-void meta_texture_tower_set_snippet (MetaTextureTower *tower,
-                                     CoglSnippet      *snippet);
-
-G_END_DECLS
-
-#endif /* __META_TEXTURE_TOWER_H__ */
diff --git a/src/compositor/meta-window-group.c b/src/compositor/meta-window-group.c
index 16ff2db097e17210d319d1dadcf00a6a55ef3cc1..c6af609aea50f38b444f8e0436fa1008322fadce 100644
--- a/src/compositor/meta-window-group.c
+++ b/src/compositor/meta-window-group.c
@@ -92,6 +92,7 @@ meta_window_group_paint (ClutterActor        *actor,
     {
       CoglFramebuffer *fb;
       ClutterStageView *view;
+      MetaTransforms trans;
 
       fb = clutter_paint_context_get_framebuffer (paint_context);
       view = clutter_paint_context_get_stage_view (paint_context);
@@ -102,13 +103,15 @@ meta_window_group_paint (ClutterActor        *actor,
                                               screen_height,
                                               screen_width,
                                               screen_height,
-                                              &paint_x_origin,
-                                              &paint_y_origin) ||
+                                              &trans) ||
           !meta_cullable_is_untransformed (META_CULLABLE (actor)))
         {
           parent_actor_class->paint (actor, paint_context);
           return;
         }
+
+      paint_x_origin = trans.x_origin;
+      paint_y_origin = trans.y_origin;
     }
   else
     {
diff --git a/src/meson.build b/src/meson.build
index 7b456f524fb5e16904b6f2c27b7e88a8ec7b0506..4ebe351b04145dfa590d4b0e8b52e5ceedb05361 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -345,8 +345,6 @@ mutter_sources = [
   'compositor/meta-surface-actor-x11.h',
   'compositor/meta-sync-ring.c',
   'compositor/meta-sync-ring.h',
-  'compositor/meta-texture-tower.c',
-  'compositor/meta-texture-tower.h',
   'compositor/meta-window-actor.c',
   'compositor/meta-window-actor-private.h',
   'compositor/meta-window-actor-x11.c',