xenocara/xserver/fb/fbtrap.c
2007-11-24 19:04:00 +00:00

162 lines
3.9 KiB
C

/*
* Copyright © 2004 Keith Packard
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation, and that the name of Keith Packard not be used in
* advertising or publicity pertaining to distribution of the software without
* specific, written prior permission. Keith Packard makes no
* representations about the suitability of this software for any purpose. It
* is provided "as is" without express or implied warranty.
*
* KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif
#include "fb.h"
#ifdef RENDER
#include "picturestr.h"
#include "mipict.h"
#include "renderedge.h"
#include "fbpict.h"
void
fbAddTraps (PicturePtr pPicture,
INT16 x_off,
INT16 y_off,
int ntrap,
xTrap *traps)
{
pixman_image_t *image = image_from_pict (pPicture, FALSE);
if (!image)
return;
pixman_add_traps (image, x_off, y_off, ntrap, (pixman_trap_t *)traps);
free_pixman_pict (pPicture, image);
}
void
fbRasterizeTrapezoid (PicturePtr pPicture,
xTrapezoid *trap,
int x_off,
int y_off)
{
pixman_image_t *image = image_from_pict (pPicture, FALSE);
if (!image)
return;
pixman_rasterize_trapezoid (image, (pixman_trapezoid_t *)trap, x_off, y_off);
free_pixman_pict (pPicture, image);
}
static int
_GreaterY (xPointFixed *a, xPointFixed *b)
{
if (a->y == b->y)
return a->x > b->x;
return a->y > b->y;
}
/*
* Note that the definition of this function is a bit odd because
* of the X coordinate space (y increasing downwards).
*/
static int
_Clockwise (xPointFixed *ref, xPointFixed *a, xPointFixed *b)
{
xPointFixed ad, bd;
ad.x = a->x - ref->x;
ad.y = a->y - ref->y;
bd.x = b->x - ref->x;
bd.y = b->y - ref->y;
return ((xFixed_32_32) bd.y * ad.x - (xFixed_32_32) ad.y * bd.x) < 0;
}
/* FIXME -- this could be made more efficient */
void
fbAddTriangles (PicturePtr pPicture,
INT16 x_off,
INT16 y_off,
int ntri,
xTriangle *tris)
{
xPointFixed *top, *left, *right, *tmp;
xTrapezoid trap;
for (; ntri; ntri--, tris++)
{
top = &tris->p1;
left = &tris->p2;
right = &tris->p3;
if (_GreaterY (top, left)) {
tmp = left; left = top; top = tmp;
}
if (_GreaterY (top, right)) {
tmp = right; right = top; top = tmp;
}
if (_Clockwise (top, right, left)) {
tmp = right; right = left; left = tmp;
}
/*
* Two cases:
*
* + +
* / \ / \
* / \ / \
* / + + \
* / -- -- \
* / -- -- \
* / --- --- \
* +-- --+
*/
trap.top = top->y;
trap.left.p1 = *top;
trap.left.p2 = *left;
trap.right.p1 = *top;
trap.right.p2 = *right;
if (right->y < left->y)
trap.bottom = right->y;
else
trap.bottom = left->y;
fbRasterizeTrapezoid (pPicture, &trap, x_off, y_off);
if (right->y < left->y)
{
trap.top = right->y;
trap.bottom = left->y;
trap.right.p1 = *right;
trap.right.p2 = *left;
}
else
{
trap.top = left->y;
trap.bottom = right->y;
trap.left.p1 = *left;
trap.left.p2 = *right;
}
fbRasterizeTrapezoid (pPicture, &trap, x_off, y_off);
}
}
#endif /* RENDER */