TinyX/fb/fbtrap.c

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2013-11-30 08:51:10 -05:00
/*
*
* 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"
#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)
{
FbBits *buf;
int bpp;
int width;
int stride;
int height;
int pxoff, pyoff;
xFixed x_off_fixed;
xFixed y_off_fixed;
RenderEdge l, r;
xFixed t, b;
fbGetDrawable(pPicture->pDrawable, buf, stride, bpp, pxoff, pyoff);
width = pPicture->pDrawable->width;
height = pPicture->pDrawable->height;
x_off += pxoff;
y_off += pyoff;
x_off_fixed = IntToxFixed(x_off);
y_off_fixed = IntToxFixed(y_off);
while (ntrap--) {
t = traps->top.y + y_off_fixed;
if (t < 0)
t = 0;
t = RenderSampleCeilY(t, bpp);
b = traps->bot.y + y_off_fixed;
if (xFixedToInt(b) >= height)
b = IntToxFixed(height) - 1;
b = RenderSampleFloorY(b, bpp);
if (b >= t) {
/* initialize edge walkers */
RenderEdgeInit(&l, bpp, t,
traps->top.l + x_off_fixed,
traps->top.y + y_off_fixed,
traps->bot.l + x_off_fixed,
traps->bot.y + y_off_fixed);
RenderEdgeInit(&r, bpp, t,
traps->top.r + x_off_fixed,
traps->top.y + y_off_fixed,
traps->bot.r + x_off_fixed,
traps->bot.y + y_off_fixed);
fbRasterizeEdges(buf, bpp, width, stride, &l, &r, t, b);
}
traps++;
}
}
void
fbRasterizeTrapezoid(PicturePtr pPicture,
xTrapezoid * trap, int x_off, int y_off)
{
FbBits *buf;
int bpp;
int width;
int stride;
int height;
int pxoff, pyoff;
xFixed x_off_fixed _X_UNUSED;
xFixed y_off_fixed;
RenderEdge l, r;
xFixed t, b;
fbGetDrawable(pPicture->pDrawable, buf, stride, bpp, pxoff, pyoff);
width = pPicture->pDrawable->width;
height = pPicture->pDrawable->height;
x_off += pxoff;
y_off += pyoff;
x_off_fixed = IntToxFixed(x_off);
y_off_fixed = IntToxFixed(y_off);
t = trap->top + y_off_fixed;
if (t < 0)
t = 0;
t = RenderSampleCeilY(t, bpp);
b = trap->bottom + y_off_fixed;
if (xFixedToInt(b) >= height)
b = IntToxFixed(height) - 1;
b = RenderSampleFloorY(b, bpp);
if (b >= t) {
/* initialize edge walkers */
RenderLineFixedEdgeInit(&l, bpp, t, &trap->left, x_off, y_off);
RenderLineFixedEdgeInit(&r, bpp, t, &trap->right, x_off, y_off);
fbRasterizeEdges(buf, bpp, width, stride, &l, &r, t, b);
}
}
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);
}
}