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cogl/cogl-path/cogl-path.c

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/*
* Cogl
*
* A Low Level GPU Graphics and Utilities API
*
* Copyright (C) 2007,2008,2009,2010,2013 Intel Corporation.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy,
* modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* Authors:
* Ivan Leben <ivan@openedhand.com>
* Øyvind Kolås <pippin@linux.intel.com>
* Neil Roberts <neil@linux.intel.com>
* Robert Bragg <robert@linux.intel.com>
*/
#include "config.h"
#include "cogl-util.h"
#include "cogl-object.h"
#include "cogl-context-private.h"
#include "cogl-journal-private.h"
#include "cogl-pipeline-private.h"
#include "cogl-framebuffer-private.h"
#include "cogl-primitive-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 "cogl-path/cogl-path.h"
#include "cogl-path-private.h"
#include "cogl-gtype-private.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 CoglPrimitive *_cogl_path_get_fill_primitive (CoglPath *path);
static void _cogl_path_build_stroke_attribute_buffer (CoglPath *path);
COGL_OBJECT_DEFINE (Path, path);
COGL_GTYPE_DEFINE_CLASS (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->fill_primitive)
{
cogl_object_unref (data->fill_primitive);
data->fill_primitive = 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->fill_primitive = 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;
}
static void
_cogl_path_stroke_nodes (CoglPath *path,
CoglFramebuffer *framebuffer,
CoglPipeline *pipeline)
{
CoglPathData *data;
CoglPipeline *copy = NULL;
unsigned int path_start;
int path_num = 0;
CoglPathNode *node;
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
_COGL_RETURN_IF_FAIL (cogl_is_framebuffer (framebuffer));
_COGL_RETURN_IF_FAIL (cogl_is_pipeline (pipeline));
data = path->data;
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)
{
CoglPrimitive *primitive;
node = &g_array_index (data->path_nodes, CoglPathNode, path_start);
primitive =
cogl_primitive_new_with_attributes (COGL_VERTICES_MODE_LINE_STRIP,
node->path_size,
&data->stroke_attributes[path_num],
1);
cogl_primitive_draw (primitive, framebuffer, pipeline);
cogl_object_unref (primitive);
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)
{
/* We need at least three stencil bits to combine clips */
if (_cogl_framebuffer_get_stencil_bits (framebuffer) >= 3)
{
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;
}
static 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;
CoglPrimitive *primitive;
_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;
}
primitive = _cogl_path_get_fill_primitive (path);
_cogl_primitive_draw (primitive, framebuffer, pipeline, flags);
}
}
/* TODO: Update to the protoype used in the Cogl master branch.
* This is experimental API but not in sync with the cogl_path_fill()
* api in Cogl master which takes explicit framebuffer and pipeline
* arguments */
void
cogl2_path_fill (CoglPath *path)
{
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
_cogl_path_fill_nodes (path,
cogl_get_draw_framebuffer (),
cogl_get_source (),
0 /* flags */);
}
/* TODO: Update to the protoype used in the Cogl master branch.
* This is experimental API but not in sync with the cogl_path_fill()
* api in Cogl master which takes explicit framebuffer and pipeline
* arguments */
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->fill_primitive = 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 CoglPrimitive *
_cogl_path_get_fill_primitive (CoglPath *path)
{
if (path->data->fill_primitive)
return path->data->fill_primitive;
_cogl_path_build_fill_attribute_buffer (path);
path->data->fill_primitive =
cogl_primitive_new_with_attributes (COGL_VERTICES_MODE_TRIANGLES,
path->data->fill_vbo_n_indices,
path->data->fill_attributes,
COGL_PATH_N_ATTRIBUTES);
cogl_primitive_set_indices (path->data->fill_primitive,
path->data->fill_vbo_indices,
path->data->fill_vbo_n_indices);
return path->data->fill_primitive;
}
static CoglClipStack *
_cogl_clip_stack_push_from_path (CoglClipStack *stack,
CoglPath *path,
CoglMatrixEntry *modelview_entry,
CoglMatrixEntry *projection_entry,
const float *viewport)
{
float x_1, y_1, x_2, y_2;
_cogl_path_get_bounds (path, &x_1, &y_1, &x_2, &y_2);
/* If the path is a simple rectangle then we can divert to pushing a
rectangle clip instead which usually won't involve the stencil
buffer */
if (_cogl_path_is_rectangle (path))
return _cogl_clip_stack_push_rectangle (stack,
x_1, y_1,
x_2, y_2,
modelview_entry,
projection_entry,
viewport);
else
{
CoglPrimitive *primitive = _cogl_path_get_fill_primitive (path);
return _cogl_clip_stack_push_primitive (stack,
primitive,
x_1, y_1, x_2, y_2,
modelview_entry,
projection_entry,
viewport);
}
}
void
cogl_framebuffer_push_path_clip (CoglFramebuffer *framebuffer,
CoglPath *path)
{
CoglMatrixEntry *modelview_entry =
_cogl_framebuffer_get_modelview_entry (framebuffer);
CoglMatrixEntry *projection_entry =
_cogl_framebuffer_get_projection_entry (framebuffer);
/* XXX: It would be nicer if we stored the private viewport as a
* vec4 so we could avoid this redundant copy. */
float viewport[] = {
framebuffer->viewport_x,
framebuffer->viewport_y,
framebuffer->viewport_width,
framebuffer->viewport_height
};
framebuffer->clip_stack =
_cogl_clip_stack_push_from_path (framebuffer->clip_stack,
path,
modelview_entry,
projection_entry,
viewport);
if (framebuffer->context->current_draw_buffer == framebuffer)
framebuffer->context->current_draw_buffer_changes |=
COGL_FRAMEBUFFER_STATE_CLIP;
}
/* XXX: deprecated */
void
cogl_clip_push_from_path (CoglPath *path)
{
cogl_framebuffer_push_path_clip (cogl_get_draw_framebuffer (), path);
}
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_with_size (data->context,
data->path_nodes->len *
sizeof (floatVec2));
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;
}
/* XXX: deprecated */
void
cogl_framebuffer_fill_path (CoglFramebuffer *framebuffer,
CoglPipeline *pipeline,
CoglPath *path)
{
_COGL_RETURN_IF_FAIL (cogl_is_framebuffer (framebuffer));
_COGL_RETURN_IF_FAIL (cogl_is_pipeline (pipeline));
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
_cogl_path_fill_nodes (path, framebuffer, pipeline, 0 /* flags */);
}
/* XXX: deprecated */
void
cogl_framebuffer_stroke_path (CoglFramebuffer *framebuffer,
CoglPipeline *pipeline,
CoglPath *path)
{
_COGL_RETURN_IF_FAIL (cogl_is_framebuffer (framebuffer));
_COGL_RETURN_IF_FAIL (cogl_is_pipeline (pipeline));
_COGL_RETURN_IF_FAIL (cogl_is_path (path));
_cogl_path_stroke_nodes (path, framebuffer, pipeline);
}
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