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st: Use blur node to render shadow pipeline

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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
1 changed files with 57 additions and 30 deletions
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87
src/st/st-private.c
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@ -382,46 +382,74 @@ _st_create_shadow_pipeline (StShadow *shadow_spec,
{
ClutterBackend *backend = clutter_get_default_backend ();
CoglContext *ctx = clutter_backend_get_cogl_context (backend);
GError *error = NULL;
static CoglPipeline *shadow_pipeline_template = NULL;
g_autoptr (ClutterPaintNode) texture_node = NULL;
g_autoptr (ClutterPaintNode) blur_node = NULL;
g_autoptr (CoglOffscreen) offscreen = NULL;
g_autoptr (GError) error = NULL;
ClutterPaintContext *paint_context;
CoglFramebuffer *fb;
CoglPipeline *pipeline;
CoglTexture *texture;
guchar *pixels_in, *pixels_out;
gint width_in, height_in, rowstride_in;
gint width_out, height_out, rowstride_out;
double sigma;
int src_height, dst_height;
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 (src_texture != NULL, NULL);
width_in = cogl_texture_get_width (src_texture);
height_in = cogl_texture_get_height (src_texture);
rowstride_in = (width_in + 3) & ~3;
sigma = shadow_spec->blur / 2.f;
n_values = ceil (3 * sigma);
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,
rowstride_in, pixels_in);
texture = cogl_texture_2d_new_with_size (ctx, dst_width, dst_height);
if (!texture)
return NULL;
pixels_out = blur_pixels (pixels_in, width_in, height_in, rowstride_in,
shadow_spec->blur * resource_scale,
&width_out, &height_out, &rowstride_out);
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)
offscreen = cogl_offscreen_new_with_texture (texture);
fb = COGL_FRAMEBUFFER (offscreen);
if (!cogl_framebuffer_allocate (fb, &error))
{
g_warning ("Failed to allocate texture: %s", error->message);
g_error_free (error);
cogl_clear_object (&texture);
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))
{
@ -438,8 +466,7 @@ _st_create_shadow_pipeline (StShadow *shadow_spec,
pipeline = cogl_pipeline_copy (shadow_pipeline_template);
cogl_pipeline_set_layer_texture (pipeline, 0, texture);
if (texture)
cogl_object_unref (texture);
cogl_clear_object (&texture);
return pipeline;
}