gnome-shell/src/st/st-scroll-view-fade.c
Adel Gadllah 43cf60f563 StScrollViewFade: Fix GLSL shader to work on r300 hardware
The number instructions in a shader is limited to 64 on r300 hardware,
the fade shader in StScrollViewFade was ending up using 97 instructions
which is way over the limit.

So refactor the shader to use less instructions by precomputing as many
values as possible outside of the conditionals. The resulting shader
ends up using 34 instructions which is well within the hardware limits.

https://bugzilla.gnome.org/show_bug.cgi?id=644589
2011-03-13 16:29:18 +01:00

433 lines
14 KiB
C

/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/*
* st-scroll-view-fade.h: Edge fade effect for StScrollView
*
* Copyright 2010 Intel Corporation.
* Copyright 2011 Adel Gadllah
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU Lesser General Public License,
* version 2.1, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
* more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#define ST_SCROLL_VIEW_FADE_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), ST_TYPE_SCROLL_VIEW_FADE, StScrollViewFadeClass))
#define ST_IS_SCROLL_VIEW_FADE_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), ST_TYPE_SCROLL_VIEW_FADE))
#define ST_SCROLL_VIEW_FADE_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), ST_TYPE_SCROLL_VIEW_FADE, StScrollViewFadeClass))
#include "st-scroll-view-fade.h"
#include "st-scroll-view.h"
#include "st-scroll-bar.h"
#include "st-scrollable.h"
#include <clutter/clutter.h>
#include <cogl/cogl.h>
typedef struct _StScrollViewFadeClass StScrollViewFadeClass;
#define DEFAULT_FADE_OFFSET 68.0f
static const gchar *fade_glsl_shader =
"uniform sampler2D tex;\n"
"uniform float height;\n"
"uniform float width;\n"
"uniform float scrollbar_width;\n"
"uniform float offset_bottom;\n"
"uniform float offset_top;\n"
"uniform bool rtl;\n"
"\n"
"void main ()\n"
"{\n"
" vec4 color = cogl_color_in * texture2D (tex, vec2 (cogl_tex_coord_in[0].xy));\n"
" float y = height * cogl_tex_coord_in[0].y;\n"
" float x = width * cogl_tex_coord_in[0].x;\n"
" float ratio = 1.0;\n"
" float fade_bottom_start = height - offset_bottom;\n"
" float ratio_top = y / offset_top;\n"
" float ratio_bottom = (height - y)/(height - fade_bottom_start);\n"
" bool in_scroll_area = ((rtl && x > scrollbar_width) || (!rtl && x < (width - scrollbar_width)));\n"
" bool fade_top = y < offset_top && in_scroll_area;\n"
" bool fade_bottom = y > fade_bottom_start && in_scroll_area;\n"
"\n"
" if (fade_top) {\n"
" ratio = ratio_top;\n"
" }\n"
" else if (fade_bottom) {\n"
" ratio = ratio_bottom;\n"
" }\n"
"\n"
" cogl_color_out = color * ratio;\n"
"}";
struct _StScrollViewFade
{
ClutterOffscreenEffect parent_instance;
/* a back pointer to our actor, so that we can query it */
ClutterActor *actor;
CoglHandle shader;
CoglHandle program;
gint tex_uniform;
gint height_uniform;
gint width_uniform;
gint scrollbar_width_uniform;
gint offset_top_uniform;
gint offset_bottom_uniform;
gint rtl_uniform;
StAdjustment *vadjustment;
guint is_attached : 1;
float fade_offset;
};
struct _StScrollViewFadeClass
{
ClutterOffscreenEffectClass parent_class;
};
G_DEFINE_TYPE (StScrollViewFade,
st_scroll_view_fade,
CLUTTER_TYPE_OFFSCREEN_EFFECT);
enum {
PROP_0,
PROP_FADE_OFFSET,
};
static gboolean
st_scroll_view_fade_pre_paint (ClutterEffect *effect)
{
StScrollViewFade *self = ST_SCROLL_VIEW_FADE (effect);
ClutterEffectClass *parent_class;
if (self->shader == COGL_INVALID_HANDLE)
return FALSE;
if (!clutter_actor_meta_get_enabled (CLUTTER_ACTOR_META (effect)))
return FALSE;
if (self->actor == NULL)
return FALSE;
if (self->program == COGL_INVALID_HANDLE)
self->program = cogl_create_program ();
if (!self->is_attached)
{
g_assert (self->shader != COGL_INVALID_HANDLE);
g_assert (self->program != COGL_INVALID_HANDLE);
cogl_program_attach_shader (self->program, self->shader);
cogl_program_link (self->program);
cogl_handle_unref (self->shader);
self->is_attached = TRUE;
self->tex_uniform =
cogl_program_get_uniform_location (self->program, "tex");
self->height_uniform =
cogl_program_get_uniform_location (self->program, "height");
self->width_uniform =
cogl_program_get_uniform_location (self->program, "width");
self->scrollbar_width_uniform =
cogl_program_get_uniform_location (self->program, "scrollbar_width");
self->rtl_uniform =
cogl_program_get_uniform_location (self->program, "rtl");
self->offset_top_uniform =
cogl_program_get_uniform_location (self->program, "offset_top");
self->offset_bottom_uniform =
cogl_program_get_uniform_location (self->program, "offset_bottom");
}
parent_class = CLUTTER_EFFECT_CLASS (st_scroll_view_fade_parent_class);
return parent_class->pre_paint (effect);
}
static CoglHandle
st_scroll_view_fade_create_texture (ClutterOffscreenEffect *effect,
gfloat min_width,
gfloat min_height)
{
return cogl_texture_new_with_size (min_width,
min_height,
COGL_TEXTURE_NO_SLICING,
COGL_PIXEL_FORMAT_RGBA_8888_PRE);
}
static void
st_scroll_view_fade_paint_target (ClutterOffscreenEffect *effect)
{
StScrollViewFade *self = ST_SCROLL_VIEW_FADE (effect);
ClutterOffscreenEffectClass *parent;
CoglHandle material;
gdouble value, lower, upper, page_size;
ClutterActor *vscroll = st_scroll_view_get_vscroll_bar (ST_SCROLL_VIEW (self->actor));
if (self->program == COGL_INVALID_HANDLE)
goto out;
st_adjustment_get_values (self->vadjustment, &value, &lower, &upper, NULL, NULL, &page_size);
if (self->offset_top_uniform > -1) {
if (value > lower + 0.1)
cogl_program_set_uniform_1f (self->program, self->offset_top_uniform, self->fade_offset);
else
cogl_program_set_uniform_1f (self->program, self->offset_top_uniform, 0.0f);
}
if (self->offset_bottom_uniform > -1) {
if (value < upper - page_size - 0.1)
cogl_program_set_uniform_1f (self->program, self->offset_bottom_uniform, self->fade_offset);
else
cogl_program_set_uniform_1f (self->program, self->offset_bottom_uniform, 0.0f);
}
if (self->tex_uniform > -1)
cogl_program_set_uniform_1i (self->program, self->tex_uniform, 0);
if (self->height_uniform > -1)
cogl_program_set_uniform_1f (self->program, self->height_uniform, clutter_actor_get_height (self->actor));
if (self->width_uniform > -1)
cogl_program_set_uniform_1f (self->program, self->width_uniform, clutter_actor_get_width (self->actor));
if (self->scrollbar_width_uniform > -1)
cogl_program_set_uniform_1f (self->program, self->scrollbar_width_uniform, clutter_actor_get_width (vscroll));
if (self->rtl_uniform > -1)
cogl_program_set_uniform_1i (self->program, self->rtl_uniform, (st_widget_get_direction (ST_WIDGET (self->actor)) == ST_TEXT_DIRECTION_RTL));
material = clutter_offscreen_effect_get_target (effect);
cogl_material_set_user_program (material, self->program);
out:
parent = CLUTTER_OFFSCREEN_EFFECT_CLASS (st_scroll_view_fade_parent_class);
parent->paint_target (effect);
}
static void
on_vadjustment_changed (StAdjustment *adjustment,
ClutterEffect *effect)
{
gdouble value, lower, upper, page_size;
gboolean needs_fade;
st_adjustment_get_values (adjustment, &value, &lower, &upper, NULL, NULL, &page_size);
needs_fade = (value > lower + 0.1) || (value < upper - page_size - 0.1);
clutter_actor_meta_set_enabled (CLUTTER_ACTOR_META (effect), needs_fade);
}
static void
st_scroll_view_fade_set_actor (ClutterActorMeta *meta,
ClutterActor *actor)
{
StScrollViewFade *self = ST_SCROLL_VIEW_FADE (meta);
ClutterActorMetaClass *parent;
g_return_if_fail (actor == NULL || ST_IS_SCROLL_VIEW (actor));
if (self->shader == COGL_INVALID_HANDLE)
{
clutter_actor_meta_set_enabled (meta, FALSE);
return;
}
if (self->vadjustment)
{
g_signal_handlers_disconnect_by_func (self->vadjustment,
(gpointer)on_vadjustment_changed,
self);
self->vadjustment = NULL;
}
if (actor)
{
StScrollView *scroll_view = ST_SCROLL_VIEW (actor);
StScrollBar *vscroll = ST_SCROLL_BAR (st_scroll_view_get_vscroll_bar (scroll_view));
self->vadjustment = ST_ADJUSTMENT (st_scroll_bar_get_adjustment (vscroll));
g_signal_connect (self->vadjustment, "changed",
G_CALLBACK (on_vadjustment_changed),
self);
on_vadjustment_changed (self->vadjustment, CLUTTER_EFFECT (self));
}
parent = CLUTTER_ACTOR_META_CLASS (st_scroll_view_fade_parent_class);
parent->set_actor (meta, actor);
/* we keep a back pointer here, to avoid going through the ActorMeta */
self->actor = clutter_actor_meta_get_actor (meta);
}
static void
st_scroll_view_fade_dispose (GObject *gobject)
{
StScrollViewFade *self = ST_SCROLL_VIEW_FADE (gobject);
if (self->program != COGL_INVALID_HANDLE)
{
cogl_handle_unref (self->program);
self->program = COGL_INVALID_HANDLE;
self->shader = COGL_INVALID_HANDLE;
}
if (self->vadjustment)
{
g_signal_handlers_disconnect_by_func (self->vadjustment,
(gpointer)on_vadjustment_changed,
self);
self->vadjustment = NULL;
}
self->actor = NULL;
G_OBJECT_CLASS (st_scroll_view_fade_parent_class)->dispose (gobject);
}
static void
st_scroll_view_fade_set_offset (StScrollViewFade *self,
float fade_offset)
{
if (self->fade_offset == fade_offset)
return;
g_object_freeze_notify (G_OBJECT (self));
self->fade_offset = fade_offset;
if (self->actor != NULL)
clutter_actor_queue_redraw (self->actor);
g_object_notify (G_OBJECT (self), "fade-offset");
g_object_thaw_notify (G_OBJECT (self));
}
static void
st_scroll_view_fade_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
StScrollViewFade *self = ST_SCROLL_VIEW_FADE (object);
switch (prop_id)
{
case PROP_FADE_OFFSET:
st_scroll_view_fade_set_offset (self, g_value_get_float (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
st_scroll_view_fade_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
StScrollViewFade *self = ST_SCROLL_VIEW_FADE (object);
switch (prop_id)
{
case PROP_FADE_OFFSET:
g_value_set_float (value, self->fade_offset);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
st_scroll_view_fade_class_init (StScrollViewFadeClass *klass)
{
ClutterEffectClass *effect_class = CLUTTER_EFFECT_CLASS (klass);
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
ClutterOffscreenEffectClass *offscreen_class;
ClutterActorMetaClass *meta_class = CLUTTER_ACTOR_META_CLASS (klass);
gobject_class->dispose = st_scroll_view_fade_dispose;
gobject_class->get_property = st_scroll_view_fade_get_property;
gobject_class->set_property = st_scroll_view_fade_set_property;
meta_class->set_actor = st_scroll_view_fade_set_actor;
effect_class->pre_paint = st_scroll_view_fade_pre_paint;
offscreen_class = CLUTTER_OFFSCREEN_EFFECT_CLASS (klass);
offscreen_class->create_texture = st_scroll_view_fade_create_texture;
offscreen_class->paint_target = st_scroll_view_fade_paint_target;
g_object_class_install_property (gobject_class,
PROP_FADE_OFFSET,
g_param_spec_float ("fade-offset",
"Fade Offset",
"The height of the area which is faded at the edge",
0.f, G_MAXFLOAT, DEFAULT_FADE_OFFSET,
G_PARAM_READWRITE));
}
static void
st_scroll_view_fade_init (StScrollViewFade *self)
{
static CoglHandle shader = COGL_INVALID_HANDLE;
if (shader == COGL_INVALID_HANDLE)
{
if (clutter_feature_available (CLUTTER_FEATURE_SHADERS_GLSL))
{
shader = cogl_create_shader (COGL_SHADER_TYPE_FRAGMENT);
cogl_shader_source (shader, fade_glsl_shader);
cogl_shader_compile (shader);
if (!cogl_shader_is_compiled (shader))
{
gchar *log_buf = cogl_shader_get_info_log (shader);
g_warning (G_STRLOC ": Unable to compile the fade shader: %s",
log_buf);
g_free (log_buf);
cogl_handle_unref (shader);
shader = COGL_INVALID_HANDLE;
}
}
}
self->shader = shader;
self->is_attached = FALSE;
self->tex_uniform = -1;
self->height_uniform = -1;
self->width_uniform = -1;
self->scrollbar_width_uniform = -1;
self->rtl_uniform = -1;
self->offset_top_uniform = -1;
self->offset_bottom_uniform = -1;
self->fade_offset = DEFAULT_FADE_OFFSET;
if (shader != COGL_INVALID_HANDLE)
cogl_handle_ref (self->shader);
}
ClutterEffect *
st_scroll_view_fade_new (void)
{
return g_object_new (ST_TYPE_SCROLL_VIEW_FADE, NULL);
}