/*
* 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 "cogl-clip-stack.h"
#include <string.h>
#include <gmodule.h>
#include <math.h>
#define _COGL_MAX_BEZ_RECURSE_DEPTH 16
void
_cogl_path_add_node (gboolean new_sub_path,
float x,
float y)
{
CoglPathNode new_node;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
new_node.x = x;
new_node.y = y;
new_node.path_size = 0;
if (new_sub_path || ctx->path_nodes->len == 0)
ctx->last_path = ctx->path_nodes->len;
g_array_append_val (ctx->path_nodes, new_node);
g_array_index (ctx->path_nodes, CoglPathNode, ctx->last_path).path_size++;
if (ctx->path_nodes->len == 1)
{
ctx->path_nodes_min.x = ctx->path_nodes_max.x = x;
ctx->path_nodes_min.y = ctx->path_nodes_max.y = y;
}
else
{
if (x < ctx->path_nodes_min.x) ctx->path_nodes_min.x = x;
if (x > ctx->path_nodes_max.x) ctx->path_nodes_max.x = x;
if (y < ctx->path_nodes_min.y) ctx->path_nodes_min.y = y;
if (y > ctx->path_nodes_max.y) ctx->path_nodes_max.y = y;
}
}
void
_cogl_path_stroke_nodes ()
{
guint path_start = 0;
gulong enable_flags = COGL_ENABLE_VERTEX_ARRAY;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
enable_flags |= cogl_material_get_cogl_enable_flags (ctx->source_material);
cogl_enable (enable_flags);
cogl_material_flush_gl_state (ctx->source_material,
COGL_MATERIAL_FLUSH_DISABLE_MASK,
(guint32)~0, /* disable all texture layers */
NULL);
_cogl_current_matrix_state_flush ();
while (path_start < ctx->path_nodes->len)
{
CoglPathNode *path = &g_array_index (ctx->path_nodes, CoglPathNode,
path_start);
GE( glVertexPointer (2, GL_FLOAT, sizeof (CoglPathNode),
(guchar *) path
+ G_STRUCT_OFFSET (CoglPathNode, x)) );
GE( glDrawArrays (GL_LINE_STRIP, 0, path->path_size) );
path_start += path->path_size;
}
}
static void
_cogl_path_get_bounds (floatVec2 nodes_min,
floatVec2 nodes_max,
float *bounds_x,
float *bounds_y,
float *bounds_w,
float *bounds_h)
{
*bounds_x = nodes_min.x;
*bounds_y = nodes_min.y;
*bounds_w = nodes_max.x - *bounds_x;
*bounds_h = nodes_max.y - *bounds_y;
}
static gint compare_ints (gconstpointer a,
gconstpointer b)
{
return GPOINTER_TO_INT(a)-GPOINTER_TO_INT(b);
}
void
_cogl_add_path_to_stencil_buffer (floatVec2 nodes_min,
floatVec2 nodes_max,
guint path_size,
CoglPathNode *path,
gboolean merge)
{
guint path_start = 0;
guint sub_path_num = 0;
float bounds_x;
float bounds_y;
float bounds_w;
float bounds_h;
gulong enable_flags = COGL_ENABLE_VERTEX_ARRAY;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
/* Just setup a simple material that doesn't use texturing... */
cogl_material_flush_gl_state (ctx->stencil_material, NULL);
enable_flags |=
cogl_material_get_cogl_enable_flags (ctx->source_material);
cogl_enable (enable_flags);
_cogl_path_get_bounds (nodes_min, nodes_max,
&bounds_x, &bounds_y, &bounds_w, &bounds_h);
if (merge)
{
GE( glStencilMask (2) );
GE( glStencilFunc (GL_LEQUAL, 0x2, 0x6) );
}
else
{
GE( glClear (GL_STENCIL_BUFFER_BIT) );
GE( glStencilMask (1) );
GE( glStencilFunc (GL_LEQUAL, 0x1, 0x3) );
}
GE( glEnable (GL_STENCIL_TEST) );
GE( glStencilOp (GL_INVERT, GL_INVERT, GL_INVERT) );
GE( glColorMask (FALSE, FALSE, FALSE, FALSE) );
GE( glDepthMask (FALSE) );
_cogl_current_matrix_state_flush ();
while (path_start < path_size)
{
GE( glVertexPointer (2, GL_FLOAT, sizeof (CoglPathNode),
(guchar *) path
+ G_STRUCT_OFFSET (CoglPathNode, x)) );
GE( glDrawArrays (GL_TRIANGLE_FAN, 0, path->path_size) );
if (sub_path_num > 0)
{
/* Union the two stencil buffers bits into the least
significant bit */
GE( glStencilMask (merge ? 6 : 3) );
GE( glStencilOp (GL_ZERO, GL_REPLACE, GL_REPLACE) );
cogl_rectangle (bounds_x, bounds_y,
bounds_x + bounds_w, bounds_y + bounds_h);
GE( glStencilOp (GL_INVERT, GL_INVERT, GL_INVERT) );
}
GE( glStencilMask (merge ? 4 : 2) );
path_start += path->path_size;
path += path->path_size;
sub_path_num++;
}
if (merge)
{
/* Now we have the new stencil buffer in bit 1 and the old
stencil buffer in bit 0 so we need to intersect them */
GE( glStencilMask (3) );
GE( glStencilFunc (GL_NEVER, 0x2, 0x3) );
GE( glStencilOp (GL_DECR, GL_DECR, GL_DECR) );
/* Decrement all of the bits twice so that only pixels where the
value is 3 will remain */
_cogl_set_current_matrix (COGL_MATRIX_PROJECTION);
_cogl_current_matrix_push ();
_cogl_current_matrix_identity ();
/* Cogl generally assumes the modelview matrix is current, so since
* cogl_rectangle will be flushing GL state and emitting geometry
* to OpenGL it will be confused if we leave the projection matrix
* active... */
_cogl_set_current_matrix (COGL_MATRIX_MODELVIEW);
_cogl_current_matrix_push ();
_cogl_current_matrix_identity ();
cogl_rectangle (-1.0, -1.0, 1.0, 1.0);
cogl_rectangle (-1.0, -1.0, 1.0, 1.0);
_cogl_current_matrix_pop ();
_cogl_set_current_matrix (COGL_MATRIX_PROJECTION);
_cogl_current_matrix_pop ();
_cogl_set_current_matrix (COGL_MATRIX_MODELVIEW);
}
GE( glStencilMask (~(GLuint) 0) );
GE( glDepthMask (TRUE) );
GE( glColorMask (TRUE, TRUE, TRUE, TRUE) );
GE( glStencilFunc (GL_EQUAL, 0x1, 0x1) );
GE( glStencilOp (GL_KEEP, GL_KEEP, GL_KEEP) );
}
static void
_cogl_path_fill_nodes_scanlines (CoglPathNode *path,
guint path_size,
gint bounds_x,
gint bounds_y,
guint bounds_w,
guint bounds_h)
{
/* This is our edge list it stores intersections between our
* curve and scanlines, it should probably be implemented with a
* data structure that has smaller overhead for inserting the
* curve/scanline intersections.
*/
GSList *scanlines[bounds_h];
gint i;
gint prev_x;
gint prev_y;
gint first_x;
gint first_y;
gint lastdir=-2; /* last direction we vere moving */
gint lastline=-1; /* the previous scanline we added to */
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
/* clear scanline intersection lists */
for (i=0; i < bounds_h; i++)
scanlines[i]=NULL;
first_x = prev_x = (path->x);
first_y = prev_y = (path->y);
/* create scanline intersection list */
for (i=1; i < path_size; i++)
{
gint dest_x = (path[i].x);
gint dest_y = (path[i].y);
gint ydir;
gint dx;
gint dy;
gint y;
fill_close:
dx = dest_x - prev_x;
dy = dest_y - prev_y;
if (dy < 0)
ydir = -1;
else if (dy > 0)
ydir = 1;
else
ydir = 0;
/* do linear interpolation between vertexes */
for (y=prev_y; y!= dest_y; y += ydir)
{
/* only add a point if the scanline has changed and we're
* within bounds.
*/
if (y-bounds_y >= 0 &&
y-bounds_y < bounds_h &&
lastline != y)
{
gint x = prev_x + (dx * (y-prev_y)) / dy;
scanlines[ y - bounds_y ]=
g_slist_insert_sorted (scanlines[ y - bounds_y],
GINT_TO_POINTER(x),
compare_ints);
if (ydir != lastdir && /* add a double entry when changing */
lastdir!=-2) /* vertical direction */
scanlines[ y - bounds_y ]=
g_slist_insert_sorted (scanlines[ y - bounds_y],
GINT_TO_POINTER(x),
compare_ints);
lastdir = ydir;
lastline = y;
}
}
prev_x = dest_x;
prev_y = dest_y;
/* if we're on the last knot, fake the first vertex being a
next one */
if (path_size == i+1)
{
dest_x = first_x;
dest_y = first_y;
i++; /* to make the loop finally end */
goto fill_close;
}
}
{
gint spans = 0;
gint span_no;
GLfloat *coords;
/* count number of spans */
for (i=0; i < bounds_h; i++)
{
GSList *iter = scanlines[i];
while (iter)
{
GSList *next = iter->next;
if (!next)
{
break;
}
/* draw the segments that should be visible */
spans ++;
iter = next->next;
}
}
coords = g_malloc0 (spans * sizeof (GLfloat) * 3 * 2 * 2);
span_no = 0;
/* build list of triangles */
for (i=0; i < bounds_h; i++)
{
GSList *iter = scanlines[i];
while (iter)
{
GSList *next = iter->next;
GLfloat x0, x1;
GLfloat y0, y1;
if (!next)
break;
x0 = GPOINTER_TO_INT (iter->data);
x1 = GPOINTER_TO_INT (next->data);
y0 = bounds_y + i;
y1 = bounds_y + i + 1.0625f;
/* render scanlines 1.0625 high to avoid gaps when
transformed */
coords[span_no * 12 + 0] = x0;
coords[span_no * 12 + 1] = y0;
coords[span_no * 12 + 2] = x1;
coords[span_no * 12 + 3] = y0;
coords[span_no * 12 + 4] = x1;
coords[span_no * 12 + 5] = y1;
coords[span_no * 12 + 6] = x0;
coords[span_no * 12 + 7] = y0;
coords[span_no * 12 + 8] = x0;
coords[span_no * 12 + 9] = y1;
coords[span_no * 12 + 10] = x1;
coords[span_no * 12 + 11] = y1;
span_no ++;
iter = next->next;
}
}
for (i=0; i < bounds_h; i++)
{
g_slist_free (scanlines[i]);
}
/* render triangles */
cogl_enable (COGL_ENABLE_VERTEX_ARRAY
| (ctx->color_alpha < 255 ? COGL_ENABLE_BLEND : 0));
GE ( glVertexPointer (2, GL_FLOAT, 0, coords ) );
GE ( glDrawArrays (GL_TRIANGLES, 0, spans * 2 * 3));
g_free (coords);
}
}
void
_cogl_path_fill_nodes ()
{
float bounds_x;
float bounds_y;
float bounds_w;
float bounds_h;
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
_cogl_path_get_bounds (ctx->path_nodes_min, ctx->path_nodes_max,
&bounds_x, &bounds_y, &bounds_w, &bounds_h);
if (cogl_features_available (COGL_FEATURE_STENCIL_BUFFER))
{
_cogl_add_path_to_stencil_buffer (ctx->path_nodes_min,
ctx->path_nodes_max,
ctx->path_nodes->len,
&g_array_index (ctx->path_nodes,
CoglPathNode, 0),
ctx->clip.stencil_used);
cogl_rectangle (bounds_x, bounds_y,
bounds_x + bounds_w, bounds_y + bounds_h);
/* The stencil buffer now contains garbage so the clip area needs to
be rebuilt */
ctx->clip.stack_dirty = TRUE;
}
else
{
guint path_start = 0;
while (path_start < ctx->path_nodes->len)
{
CoglPathNode *path = &g_array_index (ctx->path_nodes, CoglPathNode,
path_start);
_cogl_path_fill_nodes_scanlines (path,
path->path_size,
bounds_x, bounds_y,
bounds_w, bounds_h);
path_start += path->path_size;
}
}
}