From 6ee3ece1036d9b3378b3c021663e4cc916a20ad2 Mon Sep 17 00:00:00 2001
From: Georges Basile Stavracas Neto <georges.stavracas@gmail.com>
Date: Sun, 5 Jul 2020 14:55:29 -0300
Subject: [PATCH] clutter/blur-effect: Switch to create_pipeline vfunc

The blur pipeline is still cached on ClutterBlurEffect, and we
simply update the uniforms when asked to create the pipeline.

Now that ClutterOffscreenEffect will use the blur pipeline, it
doesn't need to override the paint_target() vfunc anymore.

https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1355
---
 clutter/clutter/clutter-blur-effect.c | 96 +++++++++------------------
 1 file changed, 31 insertions(+), 65 deletions(-)

diff --git a/clutter/clutter/clutter-blur-effect.c b/clutter/clutter/clutter-blur-effect.c
index 5236042de..99331dce2 100644
--- a/clutter/clutter/clutter-blur-effect.c
+++ b/clutter/clutter/clutter-blur-effect.c
@@ -81,9 +81,6 @@ struct _ClutterBlurEffect
 
   gint pixel_step_uniform;
 
-  gint tex_width;
-  gint tex_height;
-
   CoglPipeline *pipeline;
 };
 
@@ -98,20 +95,41 @@ G_DEFINE_TYPE (ClutterBlurEffect,
                clutter_blur_effect,
                CLUTTER_TYPE_OFFSCREEN_EFFECT);
 
+static CoglPipeline *
+clutter_blur_effect_create_pipeline (ClutterOffscreenEffect *effect,
+                                     CoglTexture            *texture)
+{
+  ClutterBlurEffect *blur_effect = CLUTTER_BLUR_EFFECT (effect);
+
+  if (blur_effect->pixel_step_uniform > -1)
+    {
+      float pixel_step[2];
+      int tex_width, tex_height;
+
+      tex_width = cogl_texture_get_width (texture);
+      tex_height = cogl_texture_get_height (texture);
+
+      pixel_step[0] = 1.0f / tex_width;
+      pixel_step[1] = 1.0f / tex_height;
+
+      cogl_pipeline_set_uniform_float (blur_effect->pipeline,
+                                       blur_effect->pixel_step_uniform,
+                                       2, /* n_components */
+                                       1, /* count */
+                                       pixel_step);
+    }
+
+  cogl_pipeline_set_layer_texture (blur_effect->pipeline, 0, texture);
+
+  return cogl_object_ref (blur_effect->pipeline);
+}
+
 static gboolean
 clutter_blur_effect_pre_paint (ClutterEffect       *effect,
                                ClutterPaintContext *paint_context)
 {
-  ClutterBlurEffect *self = CLUTTER_BLUR_EFFECT (effect);
   ClutterEffectClass *parent_class;
 
-  if (!clutter_actor_meta_get_enabled (CLUTTER_ACTOR_META (effect)))
-    return FALSE;
-
-  self->actor = clutter_actor_meta_get_actor (CLUTTER_ACTOR_META (effect));
-  if (self->actor == NULL)
-    return FALSE;
-
   if (!clutter_feature_available (CLUTTER_FEATURE_SHADERS_GLSL))
     {
       /* if we don't have support for GLSL shaders then we
@@ -125,59 +143,7 @@ clutter_blur_effect_pre_paint (ClutterEffect       *effect,
     }
 
   parent_class = CLUTTER_EFFECT_CLASS (clutter_blur_effect_parent_class);
-  if (parent_class->pre_paint (effect, paint_context))
-    {
-      ClutterOffscreenEffect *offscreen_effect =
-        CLUTTER_OFFSCREEN_EFFECT (effect);
-      CoglHandle texture;
-
-      texture = clutter_offscreen_effect_get_texture (offscreen_effect);
-      self->tex_width = cogl_texture_get_width (texture);
-      self->tex_height = cogl_texture_get_height (texture);
-
-      if (self->pixel_step_uniform > -1)
-        {
-          gfloat pixel_step[2];
-
-          pixel_step[0] = 1.0f / self->tex_width;
-          pixel_step[1] = 1.0f / self->tex_height;
-
-          cogl_pipeline_set_uniform_float (self->pipeline,
-                                           self->pixel_step_uniform,
-                                           2, /* n_components */
-                                           1, /* count */
-                                           pixel_step);
-        }
-
-      cogl_pipeline_set_layer_texture (self->pipeline, 0, texture);
-
-      return TRUE;
-    }
-  else
-    return FALSE;
-}
-
-static void
-clutter_blur_effect_paint_target (ClutterOffscreenEffect *effect,
-                                  ClutterPaintContext    *paint_context)
-{
-  ClutterBlurEffect *self = CLUTTER_BLUR_EFFECT (effect);
-  CoglFramebuffer *framebuffer =
-    clutter_paint_context_get_framebuffer (paint_context);
-  guint8 paint_opacity;
-
-  paint_opacity = clutter_actor_get_paint_opacity (self->actor);
-
-  cogl_pipeline_set_color4ub (self->pipeline,
-                              paint_opacity,
-                              paint_opacity,
-                              paint_opacity,
-                              paint_opacity);
-
-  cogl_framebuffer_draw_rectangle (framebuffer,
-                                   self->pipeline,
-                                   0, 0,
-                                   self->tex_width, self->tex_height);
+  return parent_class->pre_paint (effect, paint_context);
 }
 
 static gboolean
@@ -229,7 +195,7 @@ clutter_blur_effect_class_init (ClutterBlurEffectClass *klass)
   effect_class->modify_paint_volume = clutter_blur_effect_modify_paint_volume;
 
   offscreen_class = CLUTTER_OFFSCREEN_EFFECT_CLASS (klass);
-  offscreen_class->paint_target = clutter_blur_effect_paint_target;
+  offscreen_class->create_pipeline = clutter_blur_effect_create_pipeline;
 }
 
 static void