bb156970de
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.
69 lines
2.6 KiB
C
69 lines
2.6 KiB
C
/*
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* Clutter.
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*
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* An OpenGL based 'interactive canvas' library.
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*
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* Authored By Neil Roberts <neil@linux.intel.com>
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*
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* Copyright (C) 2009 Intel Corporation.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __COGL_PANGO_DISPLAY_LIST_H__
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#define __COGL_PANGO_DISPLAY_LIST_H__
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#include <glib.h>
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#include <cogl/cogl.h>
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G_BEGIN_DECLS
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typedef struct _CoglPangoDisplayList CoglPangoDisplayList;
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CoglPangoDisplayList *_cogl_pango_display_list_new (void);
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void _cogl_pango_display_list_set_color (CoglPangoDisplayList *dl,
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const CoglColor *color);
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void _cogl_pango_display_list_add_texture (CoglPangoDisplayList *dl,
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CoglHandle texture,
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float x_1, float y_1,
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float x_2, float y_2,
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float tx_1, float ty_1,
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float tx_2, float ty_2);
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void _cogl_pango_display_list_add_rectangle (CoglPangoDisplayList *dl,
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float x_1, float y_1,
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float x_2, float y_2);
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void _cogl_pango_display_list_add_trapezoid (CoglPangoDisplayList *dl,
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float y_1,
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float x_11,
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float x_21,
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float y_2,
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float x_12,
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float x_22);
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void _cogl_pango_display_list_render (CoglPangoDisplayList *dl,
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CoglHandle glyph_material,
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CoglHandle solid_material);
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void _cogl_pango_display_list_clear (CoglPangoDisplayList *dl);
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void _cogl_pango_display_list_free (CoglPangoDisplayList *dl);
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G_END_DECLS
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#endif /* __COGL_PANGO_DISPLAY_LIST_H__ */
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