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c4b4500059
This makes it consistent with cogl_rectangle_with_{multi,}texture_coords.
Notably the reason cogl_rectangle_with_{multi,}texture_coords wasn't changed
instead is that the former approach lets you describe back facing rectangles.
(though technically you could pass negative width/height values to achieve
this; it doesn't seem as neat.)
441 lines
13 KiB
C
441 lines
13 KiB
C
/*
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* Clutter COGL
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*
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* A basic GL/GLES Abstraction/Utility Layer
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*
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* Authored By Matthew Allum <mallum@openedhand.com>
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*
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* Copyright (C) 2007 OpenedHand
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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, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "cogl.h"
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#include "cogl-internal.h"
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#include "cogl-context.h"
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#include "cogl-clip-stack.h"
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#include <string.h>
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#include <gmodule.h>
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#include <math.h>
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#define _COGL_MAX_BEZ_RECURSE_DEPTH 16
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void
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_cogl_path_add_node (gboolean new_sub_path,
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float x,
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float y)
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{
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CoglPathNode new_node;
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_COGL_GET_CONTEXT (ctx, NO_RETVAL);
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new_node.x = x;
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new_node.y = y;
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new_node.path_size = 0;
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if (new_sub_path || ctx->path_nodes->len == 0)
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ctx->last_path = ctx->path_nodes->len;
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g_array_append_val (ctx->path_nodes, new_node);
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g_array_index (ctx->path_nodes, CoglPathNode, ctx->last_path).path_size++;
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if (ctx->path_nodes->len == 1)
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{
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ctx->path_nodes_min.x = ctx->path_nodes_max.x = x;
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ctx->path_nodes_min.y = ctx->path_nodes_max.y = y;
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}
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else
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{
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if (x < ctx->path_nodes_min.x) ctx->path_nodes_min.x = x;
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if (x > ctx->path_nodes_max.x) ctx->path_nodes_max.x = x;
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if (y < ctx->path_nodes_min.y) ctx->path_nodes_min.y = y;
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if (y > ctx->path_nodes_max.y) ctx->path_nodes_max.y = y;
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}
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}
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void
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_cogl_path_stroke_nodes ()
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{
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guint path_start = 0;
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gulong enable_flags = COGL_ENABLE_VERTEX_ARRAY;
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_COGL_GET_CONTEXT (ctx, NO_RETVAL);
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enable_flags |= cogl_material_get_cogl_enable_flags (ctx->source_material);
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cogl_enable (enable_flags);
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cogl_material_flush_gl_state (ctx->source_material,
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COGL_MATERIAL_FLUSH_DISABLE_MASK,
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(guint32)~0, /* disable all texture layers */
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NULL);
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while (path_start < ctx->path_nodes->len)
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{
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CoglPathNode *path = &g_array_index (ctx->path_nodes, CoglPathNode,
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path_start);
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GE( glVertexPointer (2, GL_FLOAT, sizeof (CoglPathNode),
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(guchar *) path
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+ G_STRUCT_OFFSET (CoglPathNode, x)) );
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GE( glDrawArrays (GL_LINE_STRIP, 0, path->path_size) );
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path_start += path->path_size;
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}
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}
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static void
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_cogl_path_get_bounds (floatVec2 nodes_min,
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floatVec2 nodes_max,
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float *bounds_x,
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float *bounds_y,
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float *bounds_w,
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float *bounds_h)
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{
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*bounds_x = nodes_min.x;
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*bounds_y = nodes_min.y;
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*bounds_w = nodes_max.x - *bounds_x;
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*bounds_h = nodes_max.y - *bounds_y;
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}
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static gint compare_ints (gconstpointer a,
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gconstpointer b)
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{
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return GPOINTER_TO_INT(a)-GPOINTER_TO_INT(b);
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}
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void
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_cogl_add_path_to_stencil_buffer (floatVec2 nodes_min,
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floatVec2 nodes_max,
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guint path_size,
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CoglPathNode *path,
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gboolean merge)
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{
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guint path_start = 0;
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guint sub_path_num = 0;
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float bounds_x;
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float bounds_y;
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float bounds_w;
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float bounds_h;
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gulong enable_flags = COGL_ENABLE_VERTEX_ARRAY;
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_COGL_GET_CONTEXT (ctx, NO_RETVAL);
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/* Just setup a simple material that doesn't use texturing... */
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cogl_material_flush_gl_state (ctx->stencil_material, NULL);
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enable_flags |=
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cogl_material_get_cogl_enable_flags (ctx->source_material);
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cogl_enable (enable_flags);
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_cogl_path_get_bounds (nodes_min, nodes_max,
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&bounds_x, &bounds_y, &bounds_w, &bounds_h);
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if (merge)
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{
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GE( glStencilMask (2) );
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GE( glStencilFunc (GL_LEQUAL, 0x2, 0x6) );
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}
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else
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{
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GE( glClear (GL_STENCIL_BUFFER_BIT) );
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GE( glStencilMask (1) );
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GE( glStencilFunc (GL_LEQUAL, 0x1, 0x3) );
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}
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GE( glEnable (GL_STENCIL_TEST) );
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GE( glStencilOp (GL_INVERT, GL_INVERT, GL_INVERT) );
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GE( glColorMask (FALSE, FALSE, FALSE, FALSE) );
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GE( glDepthMask (FALSE) );
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while (path_start < path_size)
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{
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GE( glVertexPointer (2, GL_FLOAT, sizeof (CoglPathNode),
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(guchar *) path
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+ G_STRUCT_OFFSET (CoglPathNode, x)) );
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GE( glDrawArrays (GL_TRIANGLE_FAN, 0, path->path_size) );
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if (sub_path_num > 0)
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{
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/* Union the two stencil buffers bits into the least
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significant bit */
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GE( glStencilMask (merge ? 6 : 3) );
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GE( glStencilOp (GL_ZERO, GL_REPLACE, GL_REPLACE) );
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cogl_rectangle (bounds_x, bounds_y,
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bounds_x + bounds_w, bounds_y + bounds_h);
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GE( glStencilOp (GL_INVERT, GL_INVERT, GL_INVERT) );
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}
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GE( glStencilMask (merge ? 4 : 2) );
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path_start += path->path_size;
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path += path->path_size;
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sub_path_num++;
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}
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if (merge)
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{
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/* Now we have the new stencil buffer in bit 1 and the old
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stencil buffer in bit 0 so we need to intersect them */
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GE( glStencilMask (3) );
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GE( glStencilFunc (GL_NEVER, 0x2, 0x3) );
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GE( glStencilOp (GL_DECR, GL_DECR, GL_DECR) );
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/* Decrement all of the bits twice so that only pixels where the
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value is 3 will remain */
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GE( glPushMatrix () );
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GE( glLoadIdentity () );
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GE( glMatrixMode (GL_PROJECTION) );
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GE( glPushMatrix () );
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GE( glLoadIdentity () );
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cogl_rectangle (-1.0, -1.0, 1.0, 1.0);
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cogl_rectangle (-1.0, -1.0, 1.0, 1.0);
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GE( glPopMatrix () );
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GE( glMatrixMode (GL_MODELVIEW) );
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GE( glPopMatrix () );
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}
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GE( glStencilMask (~(GLuint) 0) );
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GE( glDepthMask (TRUE) );
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GE( glColorMask (TRUE, TRUE, TRUE, TRUE) );
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GE( glStencilFunc (GL_EQUAL, 0x1, 0x1) );
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GE( glStencilOp (GL_KEEP, GL_KEEP, GL_KEEP) );
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}
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static void
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_cogl_path_fill_nodes_scanlines (CoglPathNode *path,
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guint path_size,
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gint bounds_x,
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gint bounds_y,
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guint bounds_w,
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guint bounds_h)
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{
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/* This is our edge list it stores intersections between our
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* curve and scanlines, it should probably be implemented with a
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* data structure that has smaller overhead for inserting the
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* curve/scanline intersections.
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*/
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GSList *scanlines[bounds_h];
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gint i;
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gint prev_x;
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gint prev_y;
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gint first_x;
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gint first_y;
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gint lastdir=-2; /* last direction we vere moving */
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gint lastline=-1; /* the previous scanline we added to */
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_COGL_GET_CONTEXT (ctx, NO_RETVAL);
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/* clear scanline intersection lists */
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for (i=0; i < bounds_h; i++)
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scanlines[i]=NULL;
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first_x = prev_x = (path->x);
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first_y = prev_y = (path->y);
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/* create scanline intersection list */
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for (i=1; i < path_size; i++)
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{
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gint dest_x = (path[i].x);
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gint dest_y = (path[i].y);
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gint ydir;
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gint dx;
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gint dy;
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gint y;
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fill_close:
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dx = dest_x - prev_x;
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dy = dest_y - prev_y;
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if (dy < 0)
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ydir = -1;
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else if (dy > 0)
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ydir = 1;
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else
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ydir = 0;
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/* do linear interpolation between vertexes */
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for (y=prev_y; y!= dest_y; y += ydir)
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{
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/* only add a point if the scanline has changed and we're
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* within bounds.
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*/
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if (y-bounds_y >= 0 &&
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y-bounds_y < bounds_h &&
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lastline != y)
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{
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gint x = prev_x + (dx * (y-prev_y)) / dy;
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scanlines[ y - bounds_y ]=
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g_slist_insert_sorted (scanlines[ y - bounds_y],
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GINT_TO_POINTER(x),
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compare_ints);
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if (ydir != lastdir && /* add a double entry when changing */
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lastdir!=-2) /* vertical direction */
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scanlines[ y - bounds_y ]=
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g_slist_insert_sorted (scanlines[ y - bounds_y],
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GINT_TO_POINTER(x),
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compare_ints);
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lastdir = ydir;
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lastline = y;
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}
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}
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prev_x = dest_x;
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prev_y = dest_y;
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/* if we're on the last knot, fake the first vertex being a
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next one */
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if (path_size == i+1)
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{
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dest_x = first_x;
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dest_y = first_y;
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i++; /* to make the loop finally end */
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goto fill_close;
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}
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}
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{
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gint spans = 0;
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gint span_no;
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GLfloat *coords;
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/* count number of spans */
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for (i=0; i < bounds_h; i++)
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{
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GSList *iter = scanlines[i];
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while (iter)
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{
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GSList *next = iter->next;
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if (!next)
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{
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break;
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}
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/* draw the segments that should be visible */
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spans ++;
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iter = next->next;
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}
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}
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coords = g_malloc0 (spans * sizeof (GLfloat) * 3 * 2 * 2);
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span_no = 0;
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/* build list of triangles */
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for (i=0; i < bounds_h; i++)
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{
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GSList *iter = scanlines[i];
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while (iter)
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{
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GSList *next = iter->next;
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GLfloat x0, x1;
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GLfloat y0, y1;
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if (!next)
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break;
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x0 = GPOINTER_TO_INT (iter->data);
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x1 = GPOINTER_TO_INT (next->data);
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y0 = bounds_y + i;
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y1 = bounds_y + i + 1.0625f;
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/* render scanlines 1.0625 high to avoid gaps when
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transformed */
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coords[span_no * 12 + 0] = x0;
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coords[span_no * 12 + 1] = y0;
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coords[span_no * 12 + 2] = x1;
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coords[span_no * 12 + 3] = y0;
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coords[span_no * 12 + 4] = x1;
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coords[span_no * 12 + 5] = y1;
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coords[span_no * 12 + 6] = x0;
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coords[span_no * 12 + 7] = y0;
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coords[span_no * 12 + 8] = x0;
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coords[span_no * 12 + 9] = y1;
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coords[span_no * 12 + 10] = x1;
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coords[span_no * 12 + 11] = y1;
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span_no ++;
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iter = next->next;
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}
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}
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for (i=0; i < bounds_h; i++)
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{
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g_slist_free (scanlines[i]);
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}
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/* render triangles */
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cogl_enable (COGL_ENABLE_VERTEX_ARRAY
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| (ctx->color_alpha < 255 ? COGL_ENABLE_BLEND : 0));
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GE ( glVertexPointer (2, GL_FLOAT, 0, coords ) );
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GE ( glDrawArrays (GL_TRIANGLES, 0, spans * 2 * 3));
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g_free (coords);
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}
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}
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void
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_cogl_path_fill_nodes ()
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{
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float bounds_x;
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float bounds_y;
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float bounds_w;
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float bounds_h;
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_COGL_GET_CONTEXT (ctx, NO_RETVAL);
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_cogl_path_get_bounds (ctx->path_nodes_min, ctx->path_nodes_max,
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&bounds_x, &bounds_y, &bounds_w, &bounds_h);
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if (cogl_features_available (COGL_FEATURE_STENCIL_BUFFER))
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{
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_cogl_add_path_to_stencil_buffer (ctx->path_nodes_min,
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ctx->path_nodes_max,
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ctx->path_nodes->len,
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&g_array_index (ctx->path_nodes,
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CoglPathNode, 0),
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ctx->clip.stencil_used);
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cogl_rectangle (bounds_x, bounds_y,
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bounds_x + bounds_w, bounds_y + bounds_h);
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/* The stencil buffer now contains garbage so the clip area needs to
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be rebuilt */
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ctx->clip.stack_dirty = TRUE;
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}
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else
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{
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guint path_start = 0;
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while (path_start < ctx->path_nodes->len)
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{
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CoglPathNode *path = &g_array_index (ctx->path_nodes, CoglPathNode,
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path_start);
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_cogl_path_fill_nodes_scanlines (path,
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path->path_size,
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bounds_x, bounds_y,
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bounds_w, bounds_h);
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path_start += path->path_size;
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}
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}
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}
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