6562d30ab0
scanline rasterizer fallback for GLES without working stencil buffer (would benefit from optimization/smarter choice of datastructures).
359 lines
8.9 KiB
C
359 lines
8.9 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 <string.h>
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#include <gmodule.h>
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#define _COGL_MAX_BEZ_RECURSE_DEPTH 16
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void
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cogl_rectangle (gint x,
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gint y,
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guint width,
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guint height)
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{
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_COGL_GET_CONTEXT (ctx, NO_RETVAL);
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/* 32-bit integers are not supported as coord types
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in GLES . Fixed type has got 16 bits left of the
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point which is equal to short anyway. */
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GLshort rect_verts[8] = {
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(GLshort) x, (GLshort) y,
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(GLshort) (x + width), (GLshort) y,
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(GLshort) x, (GLshort) (y + height),
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(GLshort) (x + width), (GLshort) (y + height)
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};
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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_SHORT, 0, rect_verts ) );
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GE ( glDrawArrays (GL_TRIANGLE_STRIP, 0, 4) );
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}
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void
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cogl_rectanglex (ClutterFixed x,
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ClutterFixed y,
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ClutterFixed width,
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ClutterFixed height)
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{
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_COGL_GET_CONTEXT (ctx, NO_RETVAL);
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GLfixed rect_verts[8] = {
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x, y,
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x + width, y,
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x, y + height,
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x + width, y + height
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};
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cogl_enable (COGL_ENABLE_VERTEX_ARRAY
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| (ctx->color_alpha < 255
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? COGL_ENABLE_BLEND : 0));
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GE( glVertexPointer (2, GL_FIXED, 0, rect_verts) );
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GE( glDrawArrays (GL_TRIANGLE_STRIP, 0, 4) );
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}
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#if 0
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void
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cogl_trapezoid (gint y1,
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gint x11,
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gint x21,
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gint y2,
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gint x12,
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gint x22)
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{
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_COGL_GET_CONTEXT (ctx, NO_RETVAL);
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cogl_enable (ctx->color_alpha < 255
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? COGL_ENABLE_BLEND : 0);
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GE( glBegin (GL_QUADS) );
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GE( glVertex2i (x11, y1) );
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GE( glVertex2i (x21, y1) );
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GE( glVertex2i (x22, y2) );
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GE( glVertex2i (x12, y2) );
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GE( glEnd () );
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}
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void
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cogl_trapezoidx (ClutterFixed y1,
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ClutterFixed x11,
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ClutterFixed x21,
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ClutterFixed y2,
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ClutterFixed x12,
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ClutterFixed x22)
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{
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_COGL_GET_CONTEXT (ctx, NO_RETVAL);
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cogl_enable (ctx->color_alpha < 255
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? COGL_ENABLE_BLEND : 0);
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GE( glBegin (GL_QUADS) );
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GE( glVertex2f (CLUTTER_FIXED_TO_FLOAT (x11),
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CLUTTER_FIXED_TO_FLOAT (y1)) );
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GE( glVertex2f (CLUTTER_FIXED_TO_FLOAT (x21),
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CLUTTER_FIXED_TO_FLOAT (y1)) );
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GE( glVertex2f (CLUTTER_FIXED_TO_FLOAT (x22),
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CLUTTER_FIXED_TO_FLOAT (y2)) );
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GE( glVertex2f (CLUTTER_FIXED_TO_FLOAT (x12),
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CLUTTER_FIXED_TO_FLOAT (y2)) );
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GE( glEnd () );
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}
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#endif
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void
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_cogl_path_clear_nodes ()
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{
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_COGL_GET_CONTEXT (ctx, NO_RETVAL);
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if (ctx->path_nodes)
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g_free(ctx->path_nodes);
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ctx->path_nodes = (CoglFixedVec2*) g_malloc (2 * sizeof(CoglFixedVec2));
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ctx->path_nodes_size = 0;
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ctx->path_nodes_cap = 2;
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}
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void
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_cogl_path_add_node (ClutterFixed x,
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ClutterFixed y)
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{
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_COGL_GET_CONTEXT (ctx, NO_RETVAL);
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CoglFixedVec2 *new_nodes = NULL;
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if (ctx->path_nodes_size == ctx->path_nodes_cap)
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{
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new_nodes = g_realloc (ctx->path_nodes,
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2 * ctx->path_nodes_cap
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* sizeof (CoglFixedVec2));
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if (new_nodes == NULL) return;
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ctx->path_nodes = new_nodes;
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ctx->path_nodes_cap *= 2;
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}
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ctx->path_nodes [ctx->path_nodes_size].x = x;
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ctx->path_nodes [ctx->path_nodes_size].y = y;
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ctx->path_nodes_size++;
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if (ctx->path_nodes_size == 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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static void
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_cogl_path_stroke_nodes ()
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{
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_COGL_GET_CONTEXT (ctx, NO_RETVAL);
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cogl_enable (COGL_ENABLE_VERTEX_ARRAY
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| (ctx->color_alpha < 255
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? COGL_ENABLE_BLEND : 0));
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GE( glVertexPointer (2, GL_FIXED, 0, ctx->path_nodes) );
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GE( glDrawArrays (GL_LINE_STRIP, 0, ctx->path_nodes_size) );
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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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static void
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_cogl_path_fill_nodes ()
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{
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_COGL_GET_CONTEXT (ctx, NO_RETVAL);
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guint bounds_x;
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guint bounds_y;
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guint bounds_w;
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guint bounds_h;
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bounds_x = CLUTTER_FIXED_FLOOR (ctx->path_nodes_min.x);
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bounds_y = CLUTTER_FIXED_FLOOR (ctx->path_nodes_min.y);
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bounds_w = CLUTTER_FIXED_CEIL (ctx->path_nodes_max.x - ctx->path_nodes_min.x);
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bounds_h = CLUTTER_FIXED_CEIL (ctx->path_nodes_max.y - ctx->path_nodes_min.y);
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#if GOT_WORKING_STENCIL_BUFFER
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GE( glClear (GL_STENCIL_BUFFER_BIT) );
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GE( glEnable (GL_STENCIL_TEST) );
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GE( glStencilFunc (GL_ALWAYS, 0x0, 0x0) );
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GE( glStencilOp (GL_INVERT, GL_INVERT, GL_INVERT) );
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GE( glColorMask (GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE) );
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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_FIXED, 0, ctx->path_nodes) );
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GE( glDrawArrays (GL_TRIANGLE_FAN, 0, ctx->path_nodes_size) );
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GE( glStencilFunc (GL_EQUAL, 0x1, 0x1) );
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GE( glStencilOp (GL_ZERO, GL_ZERO, GL_ZERO) );
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GE( glColorMask (GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE) );
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cogl_rectangle (bounds_x, bounds_y, bounds_w, bounds_h);
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GE( glDisable (GL_STENCIL_TEST) );
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#endif
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{
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GSList *scanlines[bounds_h];
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/* This is our edge list it stores intersections between our curve and
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* scanlines */
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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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/* 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 = CLUTTER_FIXED_TO_INT (ctx->path_nodes[0].x);
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first_y = prev_y = CLUTTER_FIXED_TO_INT (ctx->path_nodes[0].y);
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/* saturate scanline intersection list */
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for (i=1; i<ctx->path_nodes_size; i++)
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{
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gint dest_x = CLUTTER_FIXED_TO_INT (ctx->path_nodes[i].x);
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gint dest_y = CLUTTER_FIXED_TO_INT (ctx->path_nodes[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
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ydir = 1;
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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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if (y-bounds_y >= 0 &&
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y-bounds_y < bounds_h)
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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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}
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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 next one */
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if (ctx->path_nodes_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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/* for each scanline */
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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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gint startx, endx;
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if (!next)
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break;
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startx = GPOINTER_TO_INT (iter->data);
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endx = GPOINTER_TO_INT (next->data);
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/* draw the segments that should be visible */
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cogl_rectangle (startx, i + bounds_y, endx - startx, 1);
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iter = next->next;
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}
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if (scanlines[i])
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g_slist_free (scanlines[i]);
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}
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}
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}
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void
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cogl_fill ()
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{
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_COGL_GET_CONTEXT (ctx, NO_RETVAL);
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if (ctx->path_nodes_size == 0)
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return;
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_cogl_path_fill_nodes();
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}
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void
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cogl_stroke ()
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{
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_COGL_GET_CONTEXT (ctx, NO_RETVAL);
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if (ctx->path_nodes_size == 0)
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return;
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_cogl_path_stroke_nodes();
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}
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