mutter/cogl/cogl-spans.c
Robert Bragg b72f255c0a Start to reduce dependence on glib
Since we've had several developers from admirable projects say they
would like to use Cogl but would really prefer not to pull in
gobject,gmodule and glib as extra dependencies we are investigating if
we can get to the point where glib is only an optional dependency.
Actually we feel like we only make minimal use of glib anyway, so it may
well be quite straightforward to achieve this.

This adds a --disable-glib configure option that can be used to disable
features that depend on glib.

Actually --disable-glib doesn't strictly disable glib at this point
because it's more helpful if cogl continues to build as we make
incremental progress towards this.

The first use of glib that this patch tackles is the use of
g_return_val_if_fail and g_return_if_fail which have been replaced with
equivalent _COGL_RETURN_VAL_IF_FAIL and _COGL_RETURN_IF_FAIL macros.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
2011-11-01 12:03:02 +00:00

176 lines
4.8 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2007,2008,2009 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/>.
*
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "math.h"
#include "cogl.h"
#include "cogl-util.h"
#include "cogl-internal.h"
#include "cogl-spans.h"
void
_cogl_span_iter_update (CoglSpanIter *iter)
{
/* Pick current span */
iter->span = &iter->spans[iter->index];
/* Offset next position by span size */
iter->next_pos = iter->pos + iter->span->size - iter->span->waste;
/* Check if span intersects the area to cover */
if (iter->next_pos <= iter->cover_start ||
iter->pos >= iter->cover_end)
{
/* Intersection undefined */
iter->intersects = FALSE;
return;
}
iter->intersects = TRUE;
/* Clip start position to coverage area */
if (iter->pos < iter->cover_start)
iter->intersect_start = iter->cover_start;
else
iter->intersect_start = iter->pos;
/* Clip end position to coverage area */
if (iter->next_pos > iter->cover_end)
iter->intersect_end = iter->cover_end;
else
iter->intersect_end = iter->next_pos;
}
void
_cogl_span_iter_begin (CoglSpanIter *iter,
const CoglSpan *spans,
int n_spans,
float normalize_factor,
float cover_start,
float cover_end,
CoglPipelineWrapMode wrap_mode)
{
float cover_start_normalized;
/* XXX: If CLAMP_TO_EDGE needs to be emulated then it needs to be
* done at a higher level than here... */
_COGL_RETURN_IF_FAIL (wrap_mode == COGL_PIPELINE_WRAP_MODE_REPEAT ||
wrap_mode == COGL_PIPELINE_WRAP_MODE_MIRRORED_REPEAT);
iter->span = NULL;
iter->spans = spans;
iter->n_spans = n_spans;
/* We always iterate in a positive direction from the origin. If
* iter->flipped == TRUE that means whoever is using this API should
* interpreted the current span as extending in the opposite direction. I.e.
* it extends to the left if iterating the X axis, or up if the Y axis. */
if (cover_start > cover_end)
{
float tmp = cover_start;
cover_start = cover_end;
cover_end = tmp;
iter->flipped = TRUE;
}
else
iter->flipped = FALSE;
/* The texture spans cover the normalized texture coordinate space ranging
* from [0,1] but to help support repeating of sliced textures we allow
* iteration of any range so we need to relate the start of the range to the
* nearest point equivalent to 0.
*/
cover_start_normalized = cover_start / normalize_factor;
iter->origin = floorf (cover_start_normalized) * normalize_factor;
iter->wrap_mode = wrap_mode;
if (wrap_mode == COGL_PIPELINE_WRAP_MODE_REPEAT)
iter->index = 0;
else if (wrap_mode == COGL_PIPELINE_WRAP_MODE_MIRRORED_REPEAT)
{
if ((int)iter->origin % 2)
{
iter->index = iter->n_spans - 1;
iter->mirror_direction = -1;
iter->flipped = !iter->flipped;
}
else
{
iter->index = 0;
iter->mirror_direction = 1;
}
}
else
g_warn_if_reached ();
iter->cover_start = cover_start;
iter->cover_end = cover_end;
iter->pos = iter->origin;
/* Update intersection */
_cogl_span_iter_update (iter);
while (iter->next_pos <= iter->cover_start)
_cogl_span_iter_next (iter);
}
void
_cogl_span_iter_next (CoglSpanIter *iter)
{
/* Move current position */
iter->pos = iter->next_pos;
if (iter->wrap_mode == COGL_PIPELINE_WRAP_MODE_REPEAT)
iter->index = (iter->index + 1) % iter->n_spans;
else if (iter->wrap_mode == COGL_PIPELINE_WRAP_MODE_MIRRORED_REPEAT)
{
iter->index += iter->mirror_direction;
if (iter->index == iter->n_spans || iter->index == -1)
{
iter->mirror_direction = -iter->mirror_direction;
iter->index += iter->mirror_direction;
iter->flipped = !iter->flipped;
}
}
else
g_warn_if_reached ();
/* Update intersection */
_cogl_span_iter_update (iter);
}
gboolean
_cogl_span_iter_end (CoglSpanIter *iter)
{
/* End reached when whole area covered */
return iter->pos >= iter->cover_end;
}