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mutter/common/cogl-primitives.c
Robert Bragg c4b4500059 Changes cogl_rectangle to take x1, y1, x2, y2 args not x1, y1, width, height 
This makes it consistent with cogl_rectangle_with_{multi,}texture_coords.
Notably the reason cogl_rectangle_with_{multi,}texture_coords wasn't changed
instead is that the former approach lets you describe back facing rectangles.
(though technically you could pass negative width/height values to achieve
 this; it doesn't seem as neat.)
2009-01-28 17:20:15 +00:00

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/*
* Clutter COGL
*
* A basic GL/GLES Abstraction/Utility Layer
*
* Authored By Matthew Allum <mallum@openedhand.com>
*
* Copyright (C) 2007 OpenedHand
*
* 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, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "cogl.h"
#include "cogl-internal.h"
#include "cogl-context.h"
#include <string.h>
#include <gmodule.h>
#include <math.h>
#define _COGL_MAX_BEZ_RECURSE_DEPTH 16
/* these are defined in the particular backend(float in gl vs fixed in gles)*/
void _cogl_path_add_node (gboolean new_sub_path,
float x,
float y);
void _cogl_path_fill_nodes ();
void _cogl_path_stroke_nodes ();
void
cogl_rectangle (float x1,
float y1,
float x2,
float y2)
{
cogl_rectangle_with_multitexture_coords (x1, y1,
x2, y2,
NULL,
0);
}
void
cogl_path_fill (void)
{
cogl_path_fill_preserve ();
cogl_path_new ();
}
void
cogl_path_fill_preserve (void)
{
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
cogl_clip_ensure ();
if (ctx->path_nodes->len == 0)
return;
_cogl_path_fill_nodes ();
}
void
cogl_path_stroke (void)
{
cogl_path_stroke_preserve ();
cogl_path_new ();
}
void
cogl_path_stroke_preserve (void)
{
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
cogl_clip_ensure ();
if (ctx->path_nodes->len == 0)
return;
_cogl_path_stroke_nodes();
}
void
cogl_path_move_to (float x,
float y)
{
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
/* FIXME: handle multiple contours maybe? */
_cogl_path_add_node (TRUE, x, y);
ctx->path_start.x = x;
ctx->path_start.y = y;
ctx->path_pen = ctx->path_start;
}
void
cogl_path_rel_move_to (float x,
float y)
{
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
cogl_path_move_to (ctx->path_pen.x + x,
ctx->path_pen.y + y);
}
void
cogl_path_line_to (float x,
float y)
{
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
_cogl_path_add_node (FALSE, x, y);
ctx->path_pen.x = x;
ctx->path_pen.y = y;
}
void
cogl_path_rel_line_to (float x,
float y)
{
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
cogl_path_line_to (ctx->path_pen.x + x,
ctx->path_pen.y + y);
}
void
cogl_path_close (void)
{
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
_cogl_path_add_node (FALSE, ctx->path_start.x, ctx->path_start.y);
ctx->path_pen = ctx->path_start;
}
void
cogl_path_new (void)
{
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
g_array_set_size (ctx->path_nodes, 0);
}
void
cogl_path_line (float x_1,
float y_1,
float x_2,
float y_2)
{
cogl_path_move_to (x_1, y_1);
cogl_path_line_to (x_2, y_2);
}
void
cogl_path_polyline (float *coords,
gint num_points)
{
gint c = 0;
cogl_path_move_to (coords[0], coords[1]);
for (c = 1; c < num_points; ++c)
cogl_path_line_to (coords[2*c], coords[2*c+1]);
}
void
cogl_path_polygon (float *coords,
gint num_points)
{
cogl_path_polyline (coords, num_points);
cogl_path_close ();
}
void
cogl_path_rectangle (float x,
float y,
float width,
float height)
{
cogl_path_move_to (x, y);
cogl_path_line_to (x + width, y);
cogl_path_line_to (x + width, y + height);
cogl_path_line_to (x, y + height);
cogl_path_close ();
}
static void
_cogl_path_arc (float center_x,
float center_y,
float radius_x,
float radius_y,
float angle_1,
float angle_2,
float angle_step,
guint 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)
cogl_path_move_to (px, py);
else
cogl_path_line_to (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);
cogl_path_line_to (px, py);
}
void
cogl_path_arc (float center_x,
float center_y,
float radius_x,
float radius_y,
float angle_1,
float angle_2)
{
float angle_step = 10;
/* it is documented that a move to is needed to create a freestanding
* arc
*/
_cogl_path_arc (center_x, center_y,
radius_x, radius_y,
angle_1, angle_2,
angle_step, 0 /* no move */);
}
void
cogl_path_arc_rel (float center_x,
float center_y,
float radius_x,
float radius_y,
float angle_1,
float angle_2,
float angle_step)
{
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
_cogl_path_arc (ctx->path_pen.x + center_x,
ctx->path_pen.y + center_y,
radius_x, radius_y,
angle_1, angle_2,
angle_step, 0 /* no move */);
}
void
cogl_path_ellipse (float center_x,
float center_y,
float radius_x,
float radius_y)
{
float angle_step = 10;
/* FIXME: if shows to be slow might be optimized
* by mirroring just a quarter of it */
_cogl_path_arc (center_x, center_y,
radius_x, radius_y,
0, 360,
angle_step, 1 /* move first */);
cogl_path_close();
}
void
cogl_path_round_rectangle (float x,
float y,
float width,
float height,
float radius,
float arc_step)
{
float inner_width = width - (radius * 2);
float inner_height = height - (radius * 2);
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
cogl_path_move_to (x, y + radius);
cogl_path_arc_rel (radius, 0,
radius, radius,
180,
270,
arc_step);
cogl_path_line_to (ctx->path_pen.x + inner_width,
ctx->path_pen.y);
cogl_path_arc_rel (0, radius,
radius, radius,
-90,
0,
arc_step);
cogl_path_line_to (ctx->path_pen.x,
ctx->path_pen.y + inner_height);
cogl_path_arc_rel (-radius, 0,
radius, radius,
0,
90,
arc_step);
cogl_path_line_to (ctx->path_pen.x - inner_width,
ctx->path_pen.y);
cogl_path_arc_rel (0, -radius,
radius, radius,
90,
180,
arc_step);
cogl_path_close ();
}
static void
_cogl_path_bezier3_sub (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;
gint 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 (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
cogl_path_curve_to (float x_1,
float y_1,
float x_2,
float y_2,
float x_3,
float y_3)
{
CoglBezCubic cubic;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
/* Prepare cubic curve */
cubic.p1 = ctx->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 (&cubic);
/* Add last point */
_cogl_path_add_node (FALSE, cubic.p4.x, cubic.p4.y);
ctx->path_pen = cubic.p4;
}
void
cogl_path_rel_curve_to (float x_1,
float y_1,
float x_2,
float y_2,
float x_3,
float y_3)
{
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
cogl_path_curve_to (ctx->path_pen.x + x_1,
ctx->path_pen.y + y_1,
ctx->path_pen.x + x_2,
ctx->path_pen.y + y_2,
ctx->path_pen.x + x_3,
ctx->path_pen.y + y_3);
}
/* If second order beziers were needed the following code could
* be re-enabled:
*/
#if 0
static void
_cogl_path_bezier2_sub (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;
gint 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 (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 (float x_1,
float y_1,
float x_2,
float y_2)
{
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
CoglBezQuad quad;
/* Prepare quadratic curve */
quad.p1 = ctx->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);
ctx->path_pen = quad.p3;
}
void
cogl_rel_curve2_to (float x_1,
float y_1,
float x_2,
float y_2)
{
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
cogl_path_curve2_to (ctx->path_pen.x + x_1,
ctx->path_pen.y + y_1,
ctx->path_pen.x + x_2,
ctx->path_pen.y + y_2);
}
#endif
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