181bf92086
Because Cogl defines the origin for texture as top left and offscreen draw buffers can be used to render to textures, we (internally) force all offscreen rendering to be upside down. (because OpenGL defines the origin to be bottom left) By forcing the users scene to be rendered upside down though we also reverse the winding order of all the drawn triangles which may interfere with the users use of backface culling. This patch ensures that we reverse the winding order for a front face (if culling is in use) while rendering offscreen so we don't conflict with the users back face culling.
225 lines
7 KiB
C
225 lines
7 KiB
C
/*
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* Cogl
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*
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* An object oriented GL/GLES Abstraction/Utility Layer
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*
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* Copyright (C) 2007,2008,2009 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, 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-util.h"
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#include "cogl-context.h"
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#include "cogl-journal-private.h"
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#include "cogl-texture-private.h"
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#include "cogl-material-private.h"
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#include "cogl-draw-buffer-private.h"
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#include <string.h>
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extern void
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_cogl_create_context_driver (CoglContext *context);
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static CoglContext *_context = NULL;
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static gboolean gl_is_indirect = FALSE;
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static gboolean
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cogl_create_context (void)
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{
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GLubyte default_texture_data[] = { 0xff, 0xff, 0xff, 0x0 };
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gulong enable_flags = 0;
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CoglHandle window_buffer;
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if (_context != NULL)
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return FALSE;
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/* Allocate context memory */
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_context = (CoglContext*) g_malloc (sizeof (CoglContext));
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/* Init default values */
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_context->feature_flags = 0;
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_context->features_cached = FALSE;
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/* Initialise the driver specific state */
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/* TODO: combine these two into one function */
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_cogl_create_context_driver (_context);
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_cogl_features_init ();
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_context->enable_flags = 0;
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_context->color_alpha = 0;
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_context->enable_backface_culling = FALSE;
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_context->flushed_front_winding = COGL_FRONT_WINDING_COUNTER_CLOCKWISE;
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_context->indirect = gl_is_indirect;
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cogl_matrix_init_identity (&_context->identity_matrix);
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cogl_matrix_init_identity (&_context->y_flip_matrix);
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cogl_matrix_scale (&_context->y_flip_matrix, 1, -1, 1);
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_context->flushed_matrix_mode = COGL_MATRIX_MODELVIEW;
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_context->texture_units = NULL;
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_context->default_material = cogl_material_new ();
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_context->source_material = NULL;
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_context->default_gl_texture_2d_tex = COGL_INVALID_HANDLE;
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_context->default_gl_texture_rect_tex = COGL_INVALID_HANDLE;
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_context->journal = g_array_new (FALSE, FALSE, sizeof (CoglJournalEntry));
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_context->logged_vertices = g_array_new (FALSE, FALSE, sizeof (GLfloat));
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_context->current_material = NULL;
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_context->current_material_flags = 0;
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memset (&_context->current_material_flush_options,
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0, sizeof (CoglMaterialFlushOptions));
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_context->current_layers = g_array_new (FALSE, FALSE,
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sizeof (CoglLayerInfo));
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_context->n_texcoord_arrays_enabled = 0;
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_context->draw_buffer_stack = _cogl_create_draw_buffer_stack ();
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window_buffer = _cogl_onscreen_new ();
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/* XXX: When setting up the window buffer, cogl_set_draw_buffer
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* assumes that the handle can be found in ctx->window_buffer */
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_context->window_buffer = window_buffer;
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cogl_set_draw_buffer (COGL_WINDOW_BUFFER, 0/* ignored */);
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_context->dirty_bound_framebuffer = TRUE;
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_context->dirty_gl_viewport = TRUE;
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_context->path_nodes = g_array_new (FALSE, FALSE, sizeof (CoglPathNode));
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_context->last_path = 0;
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_context->stencil_material = cogl_material_new ();
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_context->in_begin_gl_block = FALSE;
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_context->quad_indices_byte = COGL_INVALID_HANDLE;
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_context->quad_indices_short = COGL_INVALID_HANDLE;
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_context->quad_indices_short_len = 0;
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_context->texture_download_material = COGL_INVALID_HANDLE;
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/* Create default textures used for fall backs */
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_context->default_gl_texture_2d_tex =
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cogl_texture_new_from_data (1, /* width */
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1, /* height */
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COGL_TEXTURE_NO_SLICING,
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COGL_PIXEL_FORMAT_RGBA_8888_PRE, /* data format */
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/* internal format */
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COGL_PIXEL_FORMAT_RGBA_8888_PRE,
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0, /* auto calc row stride */
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default_texture_data);
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_context->default_gl_texture_rect_tex =
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cogl_texture_new_from_data (1, /* width */
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1, /* height */
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COGL_TEXTURE_NO_SLICING,
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COGL_PIXEL_FORMAT_RGBA_8888_PRE, /* data format */
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/* internal format */
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COGL_PIXEL_FORMAT_RGBA_8888_PRE,
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0, /* auto calc row stride */
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default_texture_data);
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cogl_set_source (_context->default_material);
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_cogl_material_flush_gl_state (_context->source_material, NULL);
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enable_flags =
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_cogl_material_get_cogl_enable_flags (_context->source_material);
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cogl_enable (enable_flags);
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_cogl_flush_face_winding ();
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return TRUE;
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}
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void
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_cogl_destroy_context ()
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{
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if (_context == NULL)
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return;
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_cogl_destroy_texture_units ();
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_cogl_free_draw_buffer_stack (_context->draw_buffer_stack);
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if (_context->path_nodes)
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g_array_free (_context->path_nodes, TRUE);
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if (_context->default_gl_texture_2d_tex)
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cogl_handle_unref (_context->default_gl_texture_2d_tex);
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if (_context->default_gl_texture_rect_tex)
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cogl_handle_unref (_context->default_gl_texture_rect_tex);
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if (_context->default_material)
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cogl_handle_unref (_context->default_material);
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if (_context->journal)
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g_array_free (_context->journal, TRUE);
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if (_context->logged_vertices)
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g_array_free (_context->logged_vertices, TRUE);
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if (_context->current_layers)
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g_array_free (_context->current_layers, TRUE);
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if (_context->quad_indices_byte)
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cogl_handle_unref (_context->quad_indices_byte);
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if (_context->quad_indices_short)
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cogl_handle_unref (_context->quad_indices_short);
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g_free (_context);
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}
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CoglContext *
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_cogl_context_get_default ()
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{
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/* Create if doesn't exist yet */
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if (_context == NULL)
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cogl_create_context ();
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return _context;
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}
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/**
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* _cogl_set_indirect_context:
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* @indirect: TRUE if GL context is indirect
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*
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* Advises COGL that the GL context is indirect (commands are sent
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* over a socket). COGL uses this information to try to avoid
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* round-trips in its use of GL, for example.
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*
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* This function cannot be called "on the fly," only before COGL
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* initializes.
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*/
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void
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_cogl_set_indirect_context (gboolean indirect)
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{
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/* we get called multiple times if someone creates
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* more than the default stage
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*/
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if (_context != NULL)
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{
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if (indirect != _context->indirect)
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g_warning ("Right now all stages will be treated as "
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"either direct or indirect, ignoring attempt "
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"to change to indirect=%d", indirect);
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return;
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}
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gl_is_indirect = indirect;
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}
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