st: Use blur node to render shadow pipeline

It is generally faster than downloading the texture, blurring
with the CPU, and uploading the blurred texture. Notice that
'n_values' is calculated differently from the blur_pixels()
function; that's because it needs to match Clutter's blur
shader interpretation of sigma [1].

[1] https://gitlab.gnome.org/GNOME/mutter/-/blob/master/clutter/clutter/clutter-blur.c#L89

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1539>
This commit is contained in:
Georges Basile Stavracas Neto 2020-12-10 12:47:23 -03:00
parent 80a5b55a7a
commit e59069c012

View File

@ -382,46 +382,74 @@ _st_create_shadow_pipeline (StShadow *shadow_spec,
{ {
ClutterBackend *backend = clutter_get_default_backend (); ClutterBackend *backend = clutter_get_default_backend ();
CoglContext *ctx = clutter_backend_get_cogl_context (backend); CoglContext *ctx = clutter_backend_get_cogl_context (backend);
GError *error = NULL; g_autoptr (ClutterPaintNode) texture_node = NULL;
g_autoptr (ClutterPaintNode) blur_node = NULL;
static CoglPipeline *shadow_pipeline_template = NULL; g_autoptr (CoglOffscreen) offscreen = NULL;
g_autoptr (GError) error = NULL;
ClutterPaintContext *paint_context;
CoglFramebuffer *fb;
CoglPipeline *pipeline; CoglPipeline *pipeline;
CoglTexture *texture; CoglTexture *texture;
guchar *pixels_in, *pixels_out; double sigma;
gint width_in, height_in, rowstride_in; int src_height, dst_height;
gint width_out, height_out, rowstride_out; int src_width, dst_width;
int n_values;
int half;
static CoglPipeline *shadow_pipeline_template = NULL;
g_return_val_if_fail (shadow_spec != NULL, NULL); g_return_val_if_fail (shadow_spec != NULL, NULL);
g_return_val_if_fail (src_texture != NULL, NULL); g_return_val_if_fail (src_texture != NULL, NULL);
width_in = cogl_texture_get_width (src_texture); sigma = shadow_spec->blur / 2.f;
height_in = cogl_texture_get_height (src_texture); n_values = ceil (3 * sigma);
rowstride_in = (width_in + 3) & ~3; half = n_values / 2;
pixels_in = g_malloc0 (rowstride_in * height_in); src_width = cogl_texture_get_width (src_texture);
src_height = cogl_texture_get_height (src_texture);
dst_width = src_width + 2 * half;
dst_height = src_height + 2 * half;
cogl_texture_get_data (src_texture, COGL_PIXEL_FORMAT_A_8, texture = cogl_texture_2d_new_with_size (ctx, dst_width, dst_height);
rowstride_in, pixels_in); if (!texture)
return NULL;
pixels_out = blur_pixels (pixels_in, width_in, height_in, rowstride_in, offscreen = cogl_offscreen_new_with_texture (texture);
shadow_spec->blur * resource_scale, fb = COGL_FRAMEBUFFER (offscreen);
&width_out, &height_out, &rowstride_out); if (!cogl_framebuffer_allocate (fb, &error))
g_free (pixels_in);
texture = COGL_TEXTURE (cogl_texture_2d_new_from_data (ctx, width_out, height_out,
COGL_PIXEL_FORMAT_A_8,
rowstride_out,
pixels_out,
&error));
if (error)
{ {
g_warning ("Failed to allocate texture: %s", error->message); cogl_clear_object (&texture);
g_error_free (error); return NULL;
} }
g_free (pixels_out); cogl_framebuffer_clear4f (fb, COGL_BUFFER_BIT_COLOR, 0.f, 0.f, 0.f, 0.f);
cogl_framebuffer_orthographic (fb, 0, 0, dst_width, dst_height, 0, 1.0);
cogl_framebuffer_scale (fb, resource_scale, resource_scale, 1);
/* Blur */
blur_node = clutter_blur_node_new (dst_width, dst_height, sigma);
clutter_paint_node_add_rectangle (blur_node,
&(ClutterActorBox) {
0.f, 0.f,
dst_width, dst_height,
});
/* Texture */
texture_node = clutter_texture_node_new (src_texture,
0,
CLUTTER_SCALING_FILTER_NEAREST,
CLUTTER_SCALING_FILTER_NEAREST);
clutter_paint_node_add_child (blur_node, texture_node);
clutter_paint_node_add_rectangle (texture_node,
&(ClutterActorBox) {
half, half,
src_width, src_height,
});
paint_context =
clutter_paint_context_new_for_framebuffer (fb, NULL, CLUTTER_PAINT_FLAG_NONE);
clutter_paint_node_paint (blur_node, paint_context);
clutter_paint_context_destroy (paint_context);
if (G_UNLIKELY (shadow_pipeline_template == NULL)) if (G_UNLIKELY (shadow_pipeline_template == NULL))
{ {
@ -438,8 +466,7 @@ _st_create_shadow_pipeline (StShadow *shadow_spec,
pipeline = cogl_pipeline_copy (shadow_pipeline_template); pipeline = cogl_pipeline_copy (shadow_pipeline_template);
cogl_pipeline_set_layer_texture (pipeline, 0, texture); cogl_pipeline_set_layer_texture (pipeline, 0, texture);
if (texture) cogl_clear_object (&texture);
cogl_object_unref (texture);
return pipeline; return pipeline;
} }