[gtk] gl renderer: Fix blur nodes with radius 0

[Timm Bäder <baedert src gnome org>]

commit e847c030bde2cfa37533c1b26bb02d2e62208fc5
Author: Timm Bäder <mail baedert org>
Date:   Tue May 7 17:20:11 2019 +0200

    gl renderer: Fix blur nodes with radius 0

 gsk/gl/gskglrenderer.c | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/gsk/gl/gskglrenderer.c b/gsk/gl/gskglrenderer.c
index 6a5c098465..29e8172aa5 100644
--- a/gsk/gl/gskglrenderer.c
+++ b/gsk/gl/gskglrenderer.c
@@ -1268,10 +1268,17 @@ render_blur_node (GskGLRenderer       *self,
   const float min_y = builder->dy + node->bounds.origin.y;
   const float max_x = min_x + node->bounds.size.width;
   const float max_y = min_y + node->bounds.size.height;
+  const float blur_radius = gsk_blur_node_get_radius (node);
   int texture_id;
   gboolean is_offscreen;
   RenderOp op;
 
+  if (blur_radius <= 0)
+    {
+      gsk_gl_renderer_add_render_ops (self, gsk_blur_node_get_child (node), builder);
+      return;
+    }
+
   /* TODO(perf): We're forcing the child offscreen even if it's a texture
    * so the resulting offscreen texture is bigger by the gaussian blur factor
    * (see gsk_blur_node_new), but we didn't have to do that if the blur