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Render pango layouts with vertex buffers

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When rendering a pango layout CoglPangoRenderer now records the
operations into a list called a CoglPangoDisplayList. The entries in
the list are either glyph renderings from a texture, rectangles or
trapezoids. Multiple consecutive glyph renderings from the same glyph
cache texture are combined into a single entry. Note the
CoglPangoDisplayList has nothing to do with a GL display list.

After the display list is built it is attached to the PangoLayout with
g_object_set_qdata so that next time the layout is rendered it can
bypass rebuilding it.

The glyph rendering entries are drawn via a VBO. The VBO is attached
to the display list so it can be used multiple times. This makes the
common case of rendering a PangoLayout contained in a single texture
subsequent times usually boil down to a single call to glDrawArrays
with an already uploaded VBO.

The VBOs are accessed via the cogl_vertex_buffer API so if VBOs are
not available in GL it will resort to a fallback.

Note this will fall apart if the pango layout is altered after the
first render. I can't find a way to detect when the layout is
altered. However this won't affect ClutterText because it creates a
new PangoLayout whenever any properties are changed.
This commit is contained in:
Neil Roberts
2009-03-25 14:18:00 +00:00
parent 9fdc9ca583
commit bb156970de
4 changed files with 482 additions and 63 deletions
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145
clutter/pango/cogl-pango-render.c
View File

@ -36,6 +36,7 @@
#include "cogl-pango-private.h"
#include "cogl-pango-glyph-cache.h"
#include "cogl-pango-display-list.h"
struct _CoglPangoRenderer
{
@ -55,9 +56,8 @@ struct _CoglPangoRenderer
gboolean use_mipmapping;
/* Array of rectangles to draw from the current texture */
GArray *glyph_rectangles;
CoglHandle glyph_texture;
/* The current display list that is being built */
CoglPangoDisplayList *display_list;
};
struct _CoglPangoRendererClass
@ -65,20 +65,6 @@ struct _CoglPangoRendererClass
PangoRendererClass class_instance;
};
static void
cogl_pango_renderer_glyphs_end (CoglPangoRenderer *priv)
{
if (priv->glyph_rectangles->len > 0)
{
float *rectangles = (float *) priv->glyph_rectangles->data;
cogl_material_set_layer (priv->glyph_material, 0, priv->glyph_texture);
cogl_set_source (priv->glyph_material);
cogl_rectangles_with_texture_coords (rectangles,
priv->glyph_rectangles->len / 8);
g_array_set_size (priv->glyph_rectangles, 0);
}
}
static void
cogl_pango_renderer_draw_glyph (CoglPangoRenderer *priv,
CoglPangoGlyphCacheValue *cache_value,
@ -86,25 +72,19 @@ cogl_pango_renderer_draw_glyph (CoglPangoRenderer *priv,
float y1)
{
float x2, y2;
float *p;
if (priv->glyph_rectangles->len > 0
&& priv->glyph_texture != cache_value->texture)
cogl_pango_renderer_glyphs_end (priv);
priv->glyph_texture = cache_value->texture;
g_return_if_fail (priv->display_list != NULL);
x2 = x1 + (float) cache_value->draw_width;
y2 = y1 + (float) cache_value->draw_height;
g_array_set_size (priv->glyph_rectangles, priv->glyph_rectangles->len + 8);
p = &g_array_index (priv->glyph_rectangles, float,
priv->glyph_rectangles->len - 8);
*(p++) = x1; *(p++) = y1;
*(p++) = x2; *(p++) = y2;
*(p++) = cache_value->tx1; *(p++) = cache_value->ty1;
*(p++) = cache_value->tx2; *(p++) = cache_value->ty2;
_cogl_pango_display_list_add_texture (priv->display_list,
cache_value->texture,
x1, y1, x2, y2,
cache_value->tx1,
cache_value->ty1,
cache_value->tx2,
cache_value->ty2);
}
static void cogl_pango_renderer_finalize (GObject *object);
@ -168,7 +148,6 @@ cogl_pango_renderer_init (CoglPangoRenderer *priv)
priv->glyph_cache = cogl_pango_glyph_cache_new (FALSE);
priv->mipmapped_glyph_cache = cogl_pango_glyph_cache_new (TRUE);
priv->use_mipmapping = FALSE;
priv->glyph_rectangles = g_array_new (FALSE, FALSE, sizeof (float));
}
static void
@ -191,7 +170,6 @@ cogl_pango_renderer_finalize (GObject *object)
cogl_pango_glyph_cache_free (priv->mipmapped_glyph_cache);
cogl_pango_glyph_cache_free (priv->glyph_cache);
g_array_free (priv->glyph_rectangles, TRUE);
G_OBJECT_CLASS (cogl_pango_renderer_parent_class)->finalize (object);
}
@ -213,6 +191,17 @@ cogl_pango_get_renderer_from_context (PangoContext *context)
return COGL_PANGO_RENDERER (renderer);
}
static GQuark
cogl_pango_render_get_display_list_key (void)
{
static GQuark key = 0;
if (G_UNLIKELY (key == 0))
key = g_quark_from_static_string ("CoglPangoDisplayList");
return key;
}
/**
* cogl_pango_render_layout_subpixel:
* @layout: a #PangoLayout
@ -232,17 +221,37 @@ cogl_pango_render_layout_subpixel (PangoLayout *layout,
const CoglColor *color,
int flags)
{
PangoContext *context;
CoglPangoRenderer *priv;
PangoContext *context;
CoglPangoRenderer *priv;
CoglPangoDisplayList *display_list;
context = pango_layout_get_context (layout);
priv = cogl_pango_get_renderer_from_context (context);
if (G_UNLIKELY (!priv))
return;
priv->color = *color;
display_list = g_object_get_qdata (G_OBJECT (layout),
cogl_pango_render_get_display_list_key ());
pango_renderer_draw_layout (PANGO_RENDERER (priv), layout, x, y);
if (display_list == NULL)
{
priv->display_list = display_list =_cogl_pango_display_list_new ();
priv->color = *color;
g_object_set_qdata_full (G_OBJECT (layout),
cogl_pango_render_get_display_list_key (),
display_list,
(GDestroyNotify) _cogl_pango_display_list_free);
pango_renderer_draw_layout (PANGO_RENDERER (priv), layout, 0, 0);
priv->display_list = NULL;
}
cogl_push_matrix ();
cogl_translate (x, y, 0);
_cogl_pango_display_list_render (display_list,
priv->glyph_material,
priv->solid_material);
cogl_pop_matrix ();
}
/**
@ -296,9 +305,19 @@ cogl_pango_render_layout_line (PangoLayoutLine *line,
if (G_UNLIKELY (!priv))
return;
priv->display_list = _cogl_pango_display_list_new ();
priv->color = *color;
pango_renderer_draw_layout_line (PANGO_RENDERER (priv), line, x, y);
cogl_material_set_color (priv->glyph_material, color);
cogl_material_set_color (priv->solid_material, color);
_cogl_pango_display_list_render (priv->display_list,
priv->glyph_material,
priv->solid_material);
_cogl_pango_display_list_free (priv->display_list);
priv->display_list = NULL;
}
void
@ -444,8 +463,7 @@ cogl_pango_renderer_set_color_for_part (PangoRenderer *renderer,
else
color = priv->color;
cogl_material_set_color (priv->solid_material, &color);
cogl_material_set_color (priv->glyph_material, &color);
_cogl_pango_display_list_set_color (priv->display_list, &color);
}
static void
@ -457,12 +475,13 @@ cogl_pango_renderer_draw_box (PangoRenderer *renderer,
{
CoglPangoRenderer *priv = COGL_PANGO_RENDERER (renderer);
cogl_set_source (priv->solid_material);
cogl_path_rectangle (x,
y - height,
x + width,
y);
cogl_path_stroke ();
g_return_if_fail (priv->display_list != NULL);
_cogl_pango_display_list_add_rectangle (priv->display_list,
x,
y - height,
x + width,
y);
}
static void
@ -500,6 +519,8 @@ cogl_pango_renderer_draw_rectangle (PangoRenderer *renderer,
CoglPangoRenderer *priv = COGL_PANGO_RENDERER (renderer);
float x1, x2, y1, y2;
g_return_if_fail (priv->display_list != NULL);
cogl_pango_renderer_set_color_for_part (renderer, part);
cogl_pango_renderer_get_device_units (renderer,
@ -509,8 +530,8 @@ cogl_pango_renderer_draw_rectangle (PangoRenderer *renderer,
x + width, y + height,
&x2, &y2);
cogl_set_source (priv->solid_material);
cogl_rectangle (x1, y1, x2, y2);
_cogl_pango_display_list_add_rectangle (priv->display_list,
x1, y1, x2, y2);
}
static void
@ -526,6 +547,8 @@ cogl_pango_renderer_draw_trapezoid (PangoRenderer *renderer,
CoglPangoRenderer *priv = COGL_PANGO_RENDERER (renderer);
float points[8];
g_return_if_fail (priv->display_list != NULL);
points[0] = (x11);
points[1] = (y1);
points[2] = (x12);
@ -537,9 +560,13 @@ cogl_pango_renderer_draw_trapezoid (PangoRenderer *renderer,
cogl_pango_renderer_set_color_for_part (renderer, part);
cogl_set_source (priv->solid_material);
cogl_path_polygon (points, 4);
cogl_path_fill ();
_cogl_pango_display_list_add_trapezoid (priv->display_list,
y1,
x11,
x21,
y2,
x12,
x22);
}
static void
@ -570,8 +597,6 @@ cogl_pango_renderer_draw_glyphs (PangoRenderer *renderer,
{
PangoFontMetrics *metrics;
cogl_pango_renderer_glyphs_end (priv);
if (font == NULL ||
(metrics = pango_font_get_metrics (font, NULL)) == NULL)
{
@ -603,15 +628,11 @@ cogl_pango_renderer_draw_glyphs (PangoRenderer *renderer,
gi->glyph);
if (cache_value == NULL)
{
cogl_pango_renderer_glyphs_end (priv);
cogl_pango_renderer_draw_box (renderer,
x,
y,
PANGO_UNKNOWN_GLYPH_WIDTH,
PANGO_UNKNOWN_GLYPH_HEIGHT);
}
cogl_pango_renderer_draw_box (renderer,
x,
y,
PANGO_UNKNOWN_GLYPH_WIDTH,
PANGO_UNKNOWN_GLYPH_HEIGHT);
else
{
float width, height;
@ -628,6 +649,4 @@ cogl_pango_renderer_draw_glyphs (PangoRenderer *renderer,
xi += gi->geometry.width;
}
cogl_pango_renderer_glyphs_end (priv);
}