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mutter/cogl/cogl2-path.c
Robert Bragg ea3d8eca91 Don't take internal references on the context 
We want applications to fully control the lifetime of a CoglContext
without having to worry that internal resources (such as the default
2d,3d and rectangle textures, or any caches we maintain) could result in
circular references that keep the context alive. We also want to avoid
making CoglContext into a special kind of object that isn't ref-counted
or that can't be used with object apis such as
cogl_object_set_user_data. Being able to reliably destroy the context is
important on platforms such as Android where you may be required
bring-up and tear-down a CoglContext numerous times throughout the
applications lifetime. A dissadvantage of this policy is that it is now
possible to leave other object such as framebuffers in an inconsistent
state if the context is unreferenced and destroyed. The documentation
states that all objects that directly or indirectly depend on a context
that has been destroyed will be left in an inconsistent state and must
not be accessed thereafter. Applications (such as Android applications)
that need to cleanly destroy and re-create Cogl resources should make
sure to manually unref these dependant objects before destroying the
context.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit 23ce51beba1bb739a224e47614a59327dfbb65af)
2012-09-17 23:06:20 +01:00

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/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2007,2008,2009,2010 Intel Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*
* Authors:
* Ivan Leben <ivan@openedhand.com>
* Øyvind Kolås <pippin@linux.intel.com>
* Neil Roberts <neil@linux.intel.com>
* Robert Bragg <robert@linux.intel.com>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "cogl-util.h"
#include "cogl-object.h"
#include "cogl-internal.h"
#include "cogl-context-private.h"
#include "cogl-journal-private.h"
#include "cogl-pipeline-private.h"
#include "cogl-pipeline-opengl-private.h"
#include "cogl-framebuffer-private.h"
#include "cogl-path-private.h"
#include "cogl-texture-private.h"
#include "cogl-primitives-private.h"
#include "cogl-private.h"
#include "cogl-attribute-private.h"
#include "cogl1-context.h"
#include "tesselator/tesselator.h"
#include <string.h>
#include <math.h>
#define _COGL_MAX_BEZ_RECURSE_DEPTH 16
static void _cogl_path_free (CoglPath *path);
static void _cogl_path_build_fill_attribute_buffer (CoglPath *path);
static void _cogl_path_build_stroke_attribute_buffer (CoglPath *path);
COGL_OBJECT_DEFINE (Path, path);
static void
_cogl_path_data_clear_vbos (CoglPathData *data)
{
int i;
if (data->fill_attribute_buffer)
{
cogl_object_unref (data->fill_attribute_buffer);
cogl_object_unref (data->fill_vbo_indices);
for (i = 0; i < COGL_PATH_N_ATTRIBUTES; i++)
cogl_object_unref (data->fill_attributes[i]);
data->fill_attribute_buffer = NULL;
}
if (data->stroke_attribute_buffer)
{
cogl_object_unref (data->stroke_attribute_buffer);
for (i = 0; i < data->stroke_n_attributes; i++)
cogl_object_unref (data->stroke_attributes[i]);
g_free (data->stroke_attributes);
data->stroke_attribute_buffer = NULL;
}
}
static void
_cogl_path_data_unref (CoglPathData *data)
{
if (--data->ref_count <= 0)
{
_cogl_path_data_clear_vbos (data);
g_array_free (data->path_nodes, TRUE);
g_slice_free (CoglPathData, data);
}
}
static void
_cogl_path_modify (CoglPath *path)
{
/* This needs to be called whenever the path is about to be modified
to implement copy-on-write semantics */
/* If there is more than one path using the data then we need to
copy the data instead */
if (path->data->ref_count != 1)
{
CoglPathData *old_data = path->data;
path->data = g_slice_dup (CoglPathData, old_data);
path->data->path_nodes = g_array_new (FALSE, FALSE,
sizeof (CoglPathNode));
g_array_append_vals (path->data->path_nodes,
old_data->path_nodes->data,
old_data->path_nodes->len);
path->data->fill_attribute_buffer = NULL;
path->data->stroke_attribute_buffer = NULL;
path->data->ref_count = 1;
_cogl_path_data_unref (old_data);
}
else
/* The path is altered so the vbos will now be invalid */
_cogl_path_data_clear_vbos (path->data);
}
void
cogl2_path_set_fill_rule (CoglPath *path,
CoglPathFillRule fill_rule)
{
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
if (path->data->fill_rule != fill_rule)
{
_cogl_path_modify (path);
path->data->fill_rule = fill_rule;
}
}
CoglPathFillRule
cogl2_path_get_fill_rule (CoglPath *path)
{
_COGL_RETURN_VAL_IF_FAIL (cogl_is_path (path), COGL_PATH_FILL_RULE_NON_ZERO);
return path->data->fill_rule;
}
static void
_cogl_path_add_node (CoglPath *path,
CoglBool new_sub_path,
float x,
float y)
{
CoglPathNode new_node;
CoglPathData *data;
_cogl_path_modify (path);
data = path->data;
new_node.x = x;
new_node.y = y;
new_node.path_size = 0;
if (new_sub_path || data->path_nodes->len == 0)
data->last_path = data->path_nodes->len;
g_array_append_val (data->path_nodes, new_node);
g_array_index (data->path_nodes, CoglPathNode, data->last_path).path_size++;
if (data->path_nodes->len == 1)
{
data->path_nodes_min.x = data->path_nodes_max.x = x;
data->path_nodes_min.y = data->path_nodes_max.y = y;
}
else
{
if (x < data->path_nodes_min.x)
data->path_nodes_min.x = x;
if (x > data->path_nodes_max.x)
data->path_nodes_max.x = x;
if (y < data->path_nodes_min.y)
data->path_nodes_min.y = y;
if (y > data->path_nodes_max.y)
data->path_nodes_max.y = y;
}
/* Once the path nodes have been modified then we'll assume it's no
longer a rectangle. cogl2_path_rectangle will set this back to
TRUE if this has been called from there */
data->is_rectangle = FALSE;
}
void
_cogl_path_stroke_nodes (CoglPath *path,
CoglFramebuffer *framebuffer,
CoglPipeline *pipeline)
{
CoglPathData *data = path->data;
CoglPipeline *copy = NULL;
unsigned int path_start;
int path_num = 0;
CoglPathNode *node;
if (data->path_nodes->len == 0)
return;
if (cogl_pipeline_get_n_layers (pipeline) != 0)
{
copy = cogl_pipeline_copy (pipeline);
_cogl_pipeline_prune_to_n_layers (copy, 0);
pipeline = copy;
}
_cogl_path_build_stroke_attribute_buffer (path);
for (path_start = 0;
path_start < data->path_nodes->len;
path_start += node->path_size)
{
node = &g_array_index (data->path_nodes, CoglPathNode, path_start);
cogl_framebuffer_vdraw_attributes (framebuffer,
pipeline,
COGL_VERTICES_MODE_LINE_STRIP,
0, node->path_size,
data->stroke_attributes[path_num],
NULL);
path_num++;
}
if (copy)
cogl_object_unref (copy);
}
void
_cogl_path_get_bounds (CoglPath *path,
float *min_x,
float *min_y,
float *max_x,
float *max_y)
{
CoglPathData *data = path->data;
if (data->path_nodes->len == 0)
{
*min_x = 0.0f;
*min_y = 0.0f;
*max_x = 0.0f;
*max_y = 0.0f;
}
else
{
*min_x = data->path_nodes_min.x;
*min_y = data->path_nodes_min.y;
*max_x = data->path_nodes_max.x;
*max_y = data->path_nodes_max.y;
}
}
static void
_cogl_path_fill_nodes_with_clipped_rectangle (CoglPath *path,
CoglFramebuffer *framebuffer,
CoglPipeline *pipeline)
{
if (!(path->data->context->private_feature_flags &
COGL_PRIVATE_FEATURE_STENCIL_BUFFER))
{
static CoglBool seen_warning = FALSE;
if (!seen_warning)
{
g_warning ("Paths can not be filled using materials with "
"sliced textures unless there is a stencil "
"buffer");
seen_warning = TRUE;
}
}
cogl_framebuffer_push_path_clip (framebuffer, path);
cogl_framebuffer_draw_rectangle (framebuffer,
pipeline,
path->data->path_nodes_min.x,
path->data->path_nodes_min.y,
path->data->path_nodes_max.x,
path->data->path_nodes_max.y);
cogl_framebuffer_pop_clip (framebuffer);
}
static CoglBool
validate_layer_cb (CoglPipelineLayer *layer, void *user_data)
{
CoglBool *needs_fallback = user_data;
CoglTexture *texture = _cogl_pipeline_layer_get_texture (layer);
/* If any of the layers of the current pipeline contain sliced
* textures or textures with waste then it won't work to draw the
* path directly. Instead we fallback to pushing the path as a clip
* on the clip-stack and drawing the path's bounding rectangle
* instead.
*/
if (texture != NULL && (cogl_texture_is_sliced (texture) ||
!_cogl_texture_can_hardware_repeat (texture)))
*needs_fallback = TRUE;
return !*needs_fallback;
}
void
_cogl_path_fill_nodes (CoglPath *path,
CoglFramebuffer *framebuffer,
CoglPipeline *pipeline,
CoglDrawFlags flags)
{
if (path->data->path_nodes->len == 0)
return;
/* If the path is a simple rectangle then we can divert to using
cogl_framebuffer_draw_rectangle which should be faster because it
can go through the journal instead of uploading the geometry just
for two triangles */
if (path->data->is_rectangle && flags == 0)
{
float x_1, y_1, x_2, y_2;
_cogl_path_get_bounds (path, &x_1, &y_1, &x_2, &y_2);
cogl_framebuffer_draw_rectangle (framebuffer,
pipeline,
x_1, y_1,
x_2, y_2);
}
else
{
CoglBool needs_fallback = FALSE;
_cogl_pipeline_foreach_layer_internal (pipeline,
validate_layer_cb,
&needs_fallback);
if (needs_fallback)
{
_cogl_path_fill_nodes_with_clipped_rectangle (path,
framebuffer,
pipeline);
return;
}
_cogl_path_build_fill_attribute_buffer (path);
_cogl_framebuffer_draw_indexed_attributes (framebuffer,
pipeline,
COGL_VERTICES_MODE_TRIANGLES,
0, /* first_vertex */
path->data->fill_vbo_n_indices,
path->data->fill_vbo_indices,
path->data->fill_attributes,
COGL_PATH_N_ATTRIBUTES,
flags);
}
}
void
cogl2_path_fill (CoglPath *path)
{
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
if (path->data->path_nodes->len == 0)
return;
/* If the path is a simple rectangle then we can divert to using
cogl_rectangle which should be faster because it can go through
the journal instead of uploading the geometry just for two
triangles */
if (path->data->is_rectangle)
{
float x_1, y_1, x_2, y_2;
_cogl_path_get_bounds (path, &x_1, &y_1, &x_2, &y_2);
cogl_rectangle (x_1, y_1, x_2, y_2);
}
else
_cogl_path_fill_nodes (path,
cogl_get_draw_framebuffer (),
cogl_get_source (),
0);
}
void
cogl2_path_stroke (CoglPath *path)
{
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
if (path->data->path_nodes->len == 0)
return;
_cogl_path_stroke_nodes (path,
cogl_get_draw_framebuffer (),
cogl_get_source ());
}
void
cogl2_path_move_to (CoglPath *path,
float x,
float y)
{
CoglPathData *data;
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
_cogl_path_add_node (path, TRUE, x, y);
data = path->data;
data->path_start.x = x;
data->path_start.y = y;
data->path_pen = data->path_start;
}
void
cogl2_path_rel_move_to (CoglPath *path,
float x,
float y)
{
CoglPathData *data;
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
data = path->data;
cogl2_path_move_to (path,
data->path_pen.x + x,
data->path_pen.y + y);
}
void
cogl2_path_line_to (CoglPath *path,
float x,
float y)
{
CoglPathData *data;
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
_cogl_path_add_node (path, FALSE, x, y);
data = path->data;
data->path_pen.x = x;
data->path_pen.y = y;
}
void
cogl2_path_rel_line_to (CoglPath *path,
float x,
float y)
{
CoglPathData *data;
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
data = path->data;
cogl2_path_line_to (path,
data->path_pen.x + x,
data->path_pen.y + y);
}
void
cogl2_path_close (CoglPath *path)
{
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
_cogl_path_add_node (path, FALSE, path->data->path_start.x,
path->data->path_start.y);
path->data->path_pen = path->data->path_start;
}
void
cogl2_path_line (CoglPath *path,
float x_1,
float y_1,
float x_2,
float y_2)
{
cogl2_path_move_to (path, x_1, y_1);
cogl2_path_line_to (path, x_2, y_2);
}
void
cogl2_path_polyline (CoglPath *path,
const float *coords,
int num_points)
{
int c = 0;
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
cogl2_path_move_to (path, coords[0], coords[1]);
for (c = 1; c < num_points; ++c)
cogl2_path_line_to (path, coords[2*c], coords[2*c+1]);
}
void
cogl2_path_polygon (CoglPath *path,
const float *coords,
int num_points)
{
cogl2_path_polyline (path, coords, num_points);
cogl2_path_close (path);
}
void
cogl2_path_rectangle (CoglPath *path,
float x_1,
float y_1,
float x_2,
float y_2)
{
CoglBool is_rectangle;
/* If the path was previously empty and the rectangle isn't mirrored
then we'll record that this is a simple rectangle path so that we
can optimise it */
is_rectangle = (path->data->path_nodes->len == 0 &&
x_2 >= x_1 &&
y_2 >= y_1);
cogl2_path_move_to (path, x_1, y_1);
cogl2_path_line_to (path, x_2, y_1);
cogl2_path_line_to (path, x_2, y_2);
cogl2_path_line_to (path, x_1, y_2);
cogl2_path_close (path);
path->data->is_rectangle = is_rectangle;
}
CoglBool
_cogl_path_is_rectangle (CoglPath *path)
{
return path->data->is_rectangle;
}
static void
_cogl_path_arc (CoglPath *path,
float center_x,
float center_y,
float radius_x,
float radius_y,
float angle_1,
float angle_2,
float angle_step,
unsigned int move_first)
{
float a = 0x0;
float cosa = 0x0;
float sina = 0x0;
float px = 0x0;
float py = 0x0;
/* Fix invalid angles */
if (angle_1 == angle_2 || angle_step == 0x0)
return;
if (angle_step < 0x0)
angle_step = -angle_step;
/* Walk the arc by given step */
a = angle_1;
while (a != angle_2)
{
cosa = cosf (a * (G_PI/180.0));
sina = sinf (a * (G_PI/180.0));
px = center_x + (cosa * radius_x);
py = center_y + (sina * radius_y);
if (a == angle_1 && move_first)
cogl2_path_move_to (path, px, py);
else
cogl2_path_line_to (path, px, py);
if (G_LIKELY (angle_2 > angle_1))
{
a += angle_step;
if (a > angle_2)
a = angle_2;
}
else
{
a -= angle_step;
if (a < angle_2)
a = angle_2;
}
}
/* Make sure the final point is drawn */
cosa = cosf (angle_2 * (G_PI/180.0));
sina = sinf (angle_2 * (G_PI/180.0));
px = center_x + (cosa * radius_x);
py = center_y + (sina * radius_y);
cogl2_path_line_to (path, px, py);
}
void
cogl2_path_arc (CoglPath *path,
float center_x,
float center_y,
float radius_x,
float radius_y,
float angle_1,
float angle_2)
{
float angle_step = 10;
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
/* it is documented that a move to is needed to create a freestanding
* arc
*/
_cogl_path_arc (path,
center_x, center_y,
radius_x, radius_y,
angle_1, angle_2,
angle_step, 0 /* no move */);
}
static void
_cogl_path_rel_arc (CoglPath *path,
float center_x,
float center_y,
float radius_x,
float radius_y,
float angle_1,
float angle_2,
float angle_step)
{
CoglPathData *data;
data = path->data;
_cogl_path_arc (path,
data->path_pen.x + center_x,
data->path_pen.y + center_y,
radius_x, radius_y,
angle_1, angle_2,
angle_step, 0 /* no move */);
}
void
cogl2_path_ellipse (CoglPath *path,
float center_x,
float center_y,
float radius_x,
float radius_y)
{
float angle_step = 10;
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
/* FIXME: if shows to be slow might be optimized
* by mirroring just a quarter of it */
_cogl_path_arc (path,
center_x, center_y,
radius_x, radius_y,
0, 360,
angle_step, 1 /* move first */);
cogl2_path_close (path);
}
void
cogl2_path_round_rectangle (CoglPath *path,
float x_1,
float y_1,
float x_2,
float y_2,
float radius,
float arc_step)
{
float inner_width = x_2 - x_1 - radius * 2;
float inner_height = y_2 - y_1 - radius * 2;
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
cogl2_path_move_to (path, x_1, y_1 + radius);
_cogl_path_rel_arc (path,
radius, 0,
radius, radius,
180,
270,
arc_step);
cogl2_path_line_to (path,
path->data->path_pen.x + inner_width,
path->data->path_pen.y);
_cogl_path_rel_arc (path,
0, radius,
radius, radius,
-90,
0,
arc_step);
cogl2_path_line_to (path,
path->data->path_pen.x,
path->data->path_pen.y + inner_height);
_cogl_path_rel_arc (path,
-radius, 0,
radius, radius,
0,
90,
arc_step);
cogl2_path_line_to (path,
path->data->path_pen.x - inner_width,
path->data->path_pen.y);
_cogl_path_rel_arc (path,
0, -radius,
radius, radius,
90,
180,
arc_step);
cogl2_path_close (path);
}
static void
_cogl_path_bezier3_sub (CoglPath *path,
CoglBezCubic *cubic)
{
CoglBezCubic cubics[_COGL_MAX_BEZ_RECURSE_DEPTH];
CoglBezCubic *cleft;
CoglBezCubic *cright;
CoglBezCubic *c;
floatVec2 dif1;
floatVec2 dif2;
floatVec2 mm;
floatVec2 c1;
floatVec2 c2;
floatVec2 c3;
floatVec2 c4;
floatVec2 c5;
int cindex;
/* Put first curve on stack */
cubics[0] = *cubic;
cindex = 0;
while (cindex >= 0)
{
c = &cubics[cindex];
/* Calculate distance of control points from their
* counterparts on the line between end points */
dif1.x = (c->p2.x * 3) - (c->p1.x * 2) - c->p4.x;
dif1.y = (c->p2.y * 3) - (c->p1.y * 2) - c->p4.y;
dif2.x = (c->p3.x * 3) - (c->p4.x * 2) - c->p1.x;
dif2.y = (c->p3.y * 3) - (c->p4.y * 2) - c->p1.y;
if (dif1.x < 0)
dif1.x = -dif1.x;
if (dif1.y < 0)
dif1.y = -dif1.y;
if (dif2.x < 0)
dif2.x = -dif2.x;
if (dif2.y < 0)
dif2.y = -dif2.y;
/* Pick the greatest of two distances */
if (dif1.x < dif2.x) dif1.x = dif2.x;
if (dif1.y < dif2.y) dif1.y = dif2.y;
/* Cancel if the curve is flat enough */
if (dif1.x + dif1.y <= 1.0 ||
cindex == _COGL_MAX_BEZ_RECURSE_DEPTH-1)
{
/* Add subdivision point (skip last) */
if (cindex == 0)
return;
_cogl_path_add_node (path, FALSE, c->p4.x, c->p4.y);
--cindex;
continue;
}
/* Left recursion goes on top of stack! */
cright = c; cleft = &cubics[++cindex];
/* Subdivide into 2 sub-curves */
c1.x = ((c->p1.x + c->p2.x) / 2);
c1.y = ((c->p1.y + c->p2.y) / 2);
mm.x = ((c->p2.x + c->p3.x) / 2);
mm.y = ((c->p2.y + c->p3.y) / 2);
c5.x = ((c->p3.x + c->p4.x) / 2);
c5.y = ((c->p3.y + c->p4.y) / 2);
c2.x = ((c1.x + mm.x) / 2);
c2.y = ((c1.y + mm.y) / 2);
c4.x = ((mm.x + c5.x) / 2);
c4.y = ((mm.y + c5.y) / 2);
c3.x = ((c2.x + c4.x) / 2);
c3.y = ((c2.y + c4.y) / 2);
/* Add left recursion to stack */
cleft->p1 = c->p1;
cleft->p2 = c1;
cleft->p3 = c2;
cleft->p4 = c3;
/* Add right recursion to stack */
cright->p1 = c3;
cright->p2 = c4;
cright->p3 = c5;
cright->p4 = c->p4;
}
}
void
cogl2_path_curve_to (CoglPath *path,
float x_1,
float y_1,
float x_2,
float y_2,
float x_3,
float y_3)
{
CoglBezCubic cubic;
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
/* Prepare cubic curve */
cubic.p1 = path->data->path_pen;
cubic.p2.x = x_1;
cubic.p2.y = y_1;
cubic.p3.x = x_2;
cubic.p3.y = y_2;
cubic.p4.x = x_3;
cubic.p4.y = y_3;
/* Run subdivision */
_cogl_path_bezier3_sub (path, &cubic);
/* Add last point */
_cogl_path_add_node (path, FALSE, cubic.p4.x, cubic.p4.y);
path->data->path_pen = cubic.p4;
}
void
cogl2_path_rel_curve_to (CoglPath *path,
float x_1,
float y_1,
float x_2,
float y_2,
float x_3,
float y_3)
{
CoglPathData *data;
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
data = path->data;
cogl2_path_curve_to (path,
data->path_pen.x + x_1,
data->path_pen.y + y_1,
data->path_pen.x + x_2,
data->path_pen.y + y_2,
data->path_pen.x + x_3,
data->path_pen.y + y_3);
}
CoglPath *
cogl2_path_new (void)
{
CoglPath *path;
CoglPathData *data;
_COGL_GET_CONTEXT (ctx, NULL);
path = g_slice_new (CoglPath);
data = path->data = g_slice_new (CoglPathData);
data->ref_count = 1;
data->context = ctx;
data->fill_rule = COGL_PATH_FILL_RULE_EVEN_ODD;
data->path_nodes = g_array_new (FALSE, FALSE, sizeof (CoglPathNode));
data->last_path = 0;
data->fill_attribute_buffer = NULL;
data->stroke_attribute_buffer = NULL;
data->is_rectangle = FALSE;
return _cogl_path_object_new (path);
}
CoglPath *
cogl_path_copy (CoglPath *old_path)
{
CoglPath *new_path;
_COGL_RETURN_VAL_IF_FAIL (cogl_is_path (old_path), NULL);
new_path = g_slice_new (CoglPath);
new_path->data = old_path->data;
new_path->data->ref_count++;
return _cogl_path_object_new (new_path);
}
static void
_cogl_path_free (CoglPath *path)
{
_cogl_path_data_unref (path->data);
g_slice_free (CoglPath, path);
}
/* If second order beziers were needed the following code could
* be re-enabled:
*/
#if 0
static void
_cogl_path_bezier2_sub (CoglPath *path,
CoglBezQuad *quad)
{
CoglBezQuad quads[_COGL_MAX_BEZ_RECURSE_DEPTH];
CoglBezQuad *qleft;
CoglBezQuad *qright;
CoglBezQuad *q;
floatVec2 mid;
floatVec2 dif;
floatVec2 c1;
floatVec2 c2;
floatVec2 c3;
int qindex;
/* Put first curve on stack */
quads[0] = *quad;
qindex = 0;
/* While stack is not empty */
while (qindex >= 0)
{
q = &quads[qindex];
/* Calculate distance of control point from its
* counterpart on the line between end points */
mid.x = ((q->p1.x + q->p3.x) / 2);
mid.y = ((q->p1.y + q->p3.y) / 2);
dif.x = (q->p2.x - mid.x);
dif.y = (q->p2.y - mid.y);
if (dif.x < 0) dif.x = -dif.x;
if (dif.y < 0) dif.y = -dif.y;
/* Cancel if the curve is flat enough */
if (dif.x + dif.y <= 1.0 ||
qindex == _COGL_MAX_BEZ_RECURSE_DEPTH - 1)
{
/* Add subdivision point (skip last) */
if (qindex == 0) return;
_cogl_path_add_node (path, FALSE, q->p3.x, q->p3.y);
--qindex; continue;
}
/* Left recursion goes on top of stack! */
qright = q; qleft = &quads[++qindex];
/* Subdivide into 2 sub-curves */
c1.x = ((q->p1.x + q->p2.x) / 2);
c1.y = ((q->p1.y + q->p2.y) / 2);
c3.x = ((q->p2.x + q->p3.x) / 2);
c3.y = ((q->p2.y + q->p3.y) / 2);
c2.x = ((c1.x + c3.x) / 2);
c2.y = ((c1.y + c3.y) / 2);
/* Add left recursion onto stack */
qleft->p1 = q->p1;
qleft->p2 = c1;
qleft->p3 = c2;
/* Add right recursion onto stack */
qright->p1 = c2;
qright->p2 = c3;
qright->p3 = q->p3;
}
}
void
cogl_path_curve2_to (CoglPath *path,
float x_1,
float y_1,
float x_2,
float y_2)
{
CoglBezQuad quad;
/* Prepare quadratic curve */
quad.p1 = path->data->path_pen;
quad.p2.x = x_1;
quad.p2.y = y_1;
quad.p3.x = x_2;
quad.p3.y = y_2;
/* Run subdivision */
_cogl_path_bezier2_sub (&quad);
/* Add last point */
_cogl_path_add_node (FALSE, quad.p3.x, quad.p3.y);
path->data->path_pen = quad.p3;
}
void
cogl_rel_curve2_to (CoglPath *path,
float x_1,
float y_1,
float x_2,
float y_2)
{
CoglPathData *data;
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
data = path->data;
cogl_path_curve2_to (data->path_pen.x + x_1,
data->path_pen.y + y_1,
data->path_pen.x + x_2,
data->path_pen.y + y_2);
}
#endif
typedef struct _CoglPathTesselator CoglPathTesselator;
typedef struct _CoglPathTesselatorVertex CoglPathTesselatorVertex;
struct _CoglPathTesselator
{
GLUtesselator *glu_tess;
GLenum primitive_type;
int vertex_number;
/* Array of CoglPathTesselatorVertex. This needs to grow when the
combine callback is called */
GArray *vertices;
/* Array of integers for the indices into the vertices array. Each
element will either be uint8_t, uint16_t or uint32_t depending on
the number of vertices */
GArray *indices;
CoglIndicesType indices_type;
/* Indices used to split fans and strips */
int index_a, index_b;
};
struct _CoglPathTesselatorVertex
{
float x, y, s, t;
};
static void
_cogl_path_tesselator_begin (GLenum type,
CoglPathTesselator *tess)
{
g_assert (type == GL_TRIANGLES ||
type == GL_TRIANGLE_FAN ||
type == GL_TRIANGLE_STRIP);
tess->primitive_type = type;
tess->vertex_number = 0;
}
static CoglIndicesType
_cogl_path_tesselator_get_indices_type_for_size (int n_vertices)
{
if (n_vertices <= 256)
return COGL_INDICES_TYPE_UNSIGNED_BYTE;
else if (n_vertices <= 65536)
return COGL_INDICES_TYPE_UNSIGNED_SHORT;
else
return COGL_INDICES_TYPE_UNSIGNED_INT;
}
static void
_cogl_path_tesselator_allocate_indices_array (CoglPathTesselator *tess)
{
switch (tess->indices_type)
{
case COGL_INDICES_TYPE_UNSIGNED_BYTE:
tess->indices = g_array_new (FALSE, FALSE, sizeof (uint8_t));
break;
case COGL_INDICES_TYPE_UNSIGNED_SHORT:
tess->indices = g_array_new (FALSE, FALSE, sizeof (uint16_t));
break;
case COGL_INDICES_TYPE_UNSIGNED_INT:
tess->indices = g_array_new (FALSE, FALSE, sizeof (uint32_t));
break;
}
}
static void
_cogl_path_tesselator_add_index (CoglPathTesselator *tess, int vertex_index)
{
switch (tess->indices_type)
{
case COGL_INDICES_TYPE_UNSIGNED_BYTE:
{
uint8_t val = vertex_index;
g_array_append_val (tess->indices, val);
}
break;
case COGL_INDICES_TYPE_UNSIGNED_SHORT:
{
uint16_t val = vertex_index;
g_array_append_val (tess->indices, val);
}
break;
case COGL_INDICES_TYPE_UNSIGNED_INT:
{
uint32_t val = vertex_index;
g_array_append_val (tess->indices, val);
}
break;
}
}
static void
_cogl_path_tesselator_vertex (void *vertex_data,
CoglPathTesselator *tess)
{
int vertex_index;
vertex_index = GPOINTER_TO_INT (vertex_data);
/* This tries to convert all of the primitives into GL_TRIANGLES
with indices to share vertices */
switch (tess->primitive_type)
{
case GL_TRIANGLES:
/* Directly use the vertex */
_cogl_path_tesselator_add_index (tess, vertex_index);
break;
case GL_TRIANGLE_FAN:
if (tess->vertex_number == 0)
tess->index_a = vertex_index;
else if (tess->vertex_number == 1)
tess->index_b = vertex_index;
else
{
/* Create a triangle with the first vertex, the previous
vertex and this vertex */
_cogl_path_tesselator_add_index (tess, tess->index_a);
_cogl_path_tesselator_add_index (tess, tess->index_b);
_cogl_path_tesselator_add_index (tess, vertex_index);
/* Next time we will use this vertex as the previous
vertex */
tess->index_b = vertex_index;
}
break;
case GL_TRIANGLE_STRIP:
if (tess->vertex_number == 0)
tess->index_a = vertex_index;
else if (tess->vertex_number == 1)
tess->index_b = vertex_index;
else
{
_cogl_path_tesselator_add_index (tess, tess->index_a);
_cogl_path_tesselator_add_index (tess, tess->index_b);
_cogl_path_tesselator_add_index (tess, vertex_index);
if (tess->vertex_number & 1)
tess->index_b = vertex_index;
else
tess->index_a = vertex_index;
}
break;
default:
g_assert_not_reached ();
}
tess->vertex_number++;
}
static void
_cogl_path_tesselator_end (CoglPathTesselator *tess)
{
tess->primitive_type = GL_FALSE;
}
static void
_cogl_path_tesselator_combine (double coords[3],
void *vertex_data[4],
float weight[4],
void **out_data,
CoglPathTesselator *tess)
{
CoglPathTesselatorVertex *vertex;
CoglIndicesType new_indices_type;
int i;
/* Add a new vertex to the array */
g_array_set_size (tess->vertices, tess->vertices->len + 1);
vertex = &g_array_index (tess->vertices,
CoglPathTesselatorVertex,
tess->vertices->len - 1);
/* The data is just the index to the vertex */
*out_data = GINT_TO_POINTER (tess->vertices->len - 1);
/* Set the coordinates of the new vertex */
vertex->x = coords[0];
vertex->y = coords[1];
/* Generate the texture coordinates as the weighted average of the
four incoming coordinates */
vertex->s = 0.0f;
vertex->t = 0.0f;
for (i = 0; i < 4; i++)
{
CoglPathTesselatorVertex *old_vertex =
&g_array_index (tess->vertices, CoglPathTesselatorVertex,
GPOINTER_TO_INT (vertex_data[i]));
vertex->s += old_vertex->s * weight[i];
vertex->t += old_vertex->t * weight[i];
}
/* Check if we've reached the limit for the data type of our indices */
new_indices_type =
_cogl_path_tesselator_get_indices_type_for_size (tess->vertices->len);
if (new_indices_type != tess->indices_type)
{
CoglIndicesType old_indices_type = new_indices_type;
GArray *old_vertices = tess->indices;
/* Copy the indices to an array of the new type */
tess->indices_type = new_indices_type;
_cogl_path_tesselator_allocate_indices_array (tess);
switch (old_indices_type)
{
case COGL_INDICES_TYPE_UNSIGNED_BYTE:
for (i = 0; i < old_vertices->len; i++)
_cogl_path_tesselator_add_index (tess,
g_array_index (old_vertices,
uint8_t, i));
break;
case COGL_INDICES_TYPE_UNSIGNED_SHORT:
for (i = 0; i < old_vertices->len; i++)
_cogl_path_tesselator_add_index (tess,
g_array_index (old_vertices,
uint16_t, i));
break;
case COGL_INDICES_TYPE_UNSIGNED_INT:
for (i = 0; i < old_vertices->len; i++)
_cogl_path_tesselator_add_index (tess,
g_array_index (old_vertices,
uint32_t, i));
break;
}
g_array_free (old_vertices, TRUE);
}
}
static void
_cogl_path_build_fill_attribute_buffer (CoglPath *path)
{
CoglPathTesselator tess;
unsigned int path_start = 0;
CoglPathData *data = path->data;
int i;
/* If we've already got a vbo then we don't need to do anything */
if (data->fill_attribute_buffer)
return;
tess.primitive_type = FALSE;
/* Generate a vertex for each point on the path */
tess.vertices = g_array_new (FALSE, FALSE, sizeof (CoglPathTesselatorVertex));
g_array_set_size (tess.vertices, data->path_nodes->len);
for (i = 0; i < data->path_nodes->len; i++)
{
CoglPathNode *node =
&g_array_index (data->path_nodes, CoglPathNode, i);
CoglPathTesselatorVertex *vertex =
&g_array_index (tess.vertices, CoglPathTesselatorVertex, i);
vertex->x = node->x;
vertex->y = node->y;
/* Add texture coordinates so that a texture would be drawn to
fit the bounding box of the path and then cropped by the
path */
if (data->path_nodes_min.x == data->path_nodes_max.x)
vertex->s = 0.0f;
else
vertex->s = ((node->x - data->path_nodes_min.x)
/ (data->path_nodes_max.x - data->path_nodes_min.x));
if (data->path_nodes_min.y == data->path_nodes_max.y)
vertex->t = 0.0f;
else
vertex->t = ((node->y - data->path_nodes_min.y)
/ (data->path_nodes_max.y - data->path_nodes_min.y));
}
tess.indices_type =
_cogl_path_tesselator_get_indices_type_for_size (data->path_nodes->len);
_cogl_path_tesselator_allocate_indices_array (&tess);
tess.glu_tess = gluNewTess ();
if (data->fill_rule == COGL_PATH_FILL_RULE_EVEN_ODD)
gluTessProperty (tess.glu_tess, GLU_TESS_WINDING_RULE,
GLU_TESS_WINDING_ODD);
else
gluTessProperty (tess.glu_tess, GLU_TESS_WINDING_RULE,
GLU_TESS_WINDING_NONZERO);
/* All vertices are on the xy-plane */
gluTessNormal (tess.glu_tess, 0.0, 0.0, 1.0);
gluTessCallback (tess.glu_tess, GLU_TESS_BEGIN_DATA,
_cogl_path_tesselator_begin);
gluTessCallback (tess.glu_tess, GLU_TESS_VERTEX_DATA,
_cogl_path_tesselator_vertex);
gluTessCallback (tess.glu_tess, GLU_TESS_END_DATA,
_cogl_path_tesselator_end);
gluTessCallback (tess.glu_tess, GLU_TESS_COMBINE_DATA,
_cogl_path_tesselator_combine);
gluTessBeginPolygon (tess.glu_tess, &tess);
while (path_start < data->path_nodes->len)
{
CoglPathNode *node =
&g_array_index (data->path_nodes, CoglPathNode, path_start);
gluTessBeginContour (tess.glu_tess);
for (i = 0; i < node->path_size; i++)
{
double vertex[3] = { node[i].x, node[i].y, 0.0 };
gluTessVertex (tess.glu_tess, vertex,
GINT_TO_POINTER (i + path_start));
}
gluTessEndContour (tess.glu_tess);
path_start += node->path_size;
}
gluTessEndPolygon (tess.glu_tess);
gluDeleteTess (tess.glu_tess);
data->fill_attribute_buffer =
cogl_attribute_buffer_new (data->context,
sizeof (CoglPathTesselatorVertex) *
tess.vertices->len,
tess.vertices->data);
g_array_free (tess.vertices, TRUE);
data->fill_attributes[0] =
cogl_attribute_new (data->fill_attribute_buffer,
"cogl_position_in",
sizeof (CoglPathTesselatorVertex),
G_STRUCT_OFFSET (CoglPathTesselatorVertex, x),
2, /* n_components */
COGL_ATTRIBUTE_TYPE_FLOAT);
data->fill_attributes[1] =
cogl_attribute_new (data->fill_attribute_buffer,
"cogl_tex_coord0_in",
sizeof (CoglPathTesselatorVertex),
G_STRUCT_OFFSET (CoglPathTesselatorVertex, s),
2, /* n_components */
COGL_ATTRIBUTE_TYPE_FLOAT);
data->fill_vbo_indices = cogl_indices_new (data->context,
tess.indices_type,
tess.indices->data,
tess.indices->len);
data->fill_vbo_n_indices = tess.indices->len;
g_array_free (tess.indices, TRUE);
}
static void
_cogl_path_build_stroke_attribute_buffer (CoglPath *path)
{
CoglPathData *data = path->data;
CoglBuffer *buffer;
unsigned int n_attributes = 0;
unsigned int path_start;
CoglPathNode *node;
floatVec2 *buffer_p;
unsigned int i;
/* If we've already got a cached vbo then we don't need to do anything */
if (data->stroke_attribute_buffer)
return;
data->stroke_attribute_buffer =
cogl_attribute_buffer_new (data->context,
data->path_nodes->len * sizeof (floatVec2),
NULL);
buffer = COGL_BUFFER (data->stroke_attribute_buffer);
buffer_p = _cogl_buffer_map_for_fill_or_fallback (buffer);
/* Copy the vertices in and count the number of sub paths. Each sub
path will form a separate attribute so we can paint the disjoint
line strips */
for (path_start = 0;
path_start < data->path_nodes->len;
path_start += node->path_size)
{
node = &g_array_index (data->path_nodes, CoglPathNode, path_start);
for (i = 0; i < node->path_size; i++)
{
buffer_p[path_start + i].x = node[i].x;
buffer_p[path_start + i].y = node[i].y;
}
n_attributes++;
}
_cogl_buffer_unmap_for_fill_or_fallback (buffer);
data->stroke_attributes = g_new (CoglAttribute *, n_attributes);
/* Now we can loop the sub paths again to create the attributes */
for (i = 0, path_start = 0;
path_start < data->path_nodes->len;
i++, path_start += node->path_size)
{
node = &g_array_index (data->path_nodes, CoglPathNode, path_start);
data->stroke_attributes[i] =
cogl_attribute_new (data->stroke_attribute_buffer,
"cogl_position_in",
sizeof (floatVec2),
path_start * sizeof (floatVec2),
2, /* n_components */
COGL_ATTRIBUTE_TYPE_FLOAT);
}
data->stroke_n_attributes = n_attributes;
}
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