mirror of
git://source.winehq.org/git/wine.git
synced 2024-09-01 09:53:38 +00:00
498 lines
15 KiB
C
498 lines
15 KiB
C
/*
|
|
* SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
|
|
* Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved.
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a
|
|
* copy of this software and associated documentation files (the "Software"),
|
|
* to deal in the Software without restriction, including without limitation
|
|
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
|
|
* and/or sell copies of the Software, and to permit persons to whom the
|
|
* Software is furnished to do so, subject to the following conditions:
|
|
*
|
|
* The above copyright notice including the dates of first publication and
|
|
* either this permission notice or a reference to
|
|
* http://oss.sgi.com/projects/FreeB/
|
|
* shall be included in all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
|
|
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
|
|
* SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
|
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
|
|
* OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
|
|
* SOFTWARE.
|
|
*
|
|
* Except as contained in this notice, the name of Silicon Graphics, Inc.
|
|
* shall not be used in advertising or otherwise to promote the sale, use or
|
|
* other dealings in this Software without prior written authorization from
|
|
* Silicon Graphics, Inc.
|
|
*/
|
|
/*
|
|
** Author: Eric Veach, July 1994.
|
|
**
|
|
*/
|
|
|
|
#include <stdarg.h>
|
|
#include <assert.h>
|
|
|
|
#include "windef.h"
|
|
#include "winbase.h"
|
|
|
|
#include "mesh.h"
|
|
#include "tess.h"
|
|
|
|
/* This structure remembers the information we need about a primitive
|
|
* to be able to render it later, once we have determined which
|
|
* primitive is able to use the most triangles.
|
|
*/
|
|
struct FaceCount {
|
|
long size; /* number of triangles used */
|
|
GLUhalfEdge *eStart; /* edge where this primitive starts */
|
|
void (*render)(GLUtesselator *, GLUhalfEdge *, long);
|
|
/* routine to render this primitive */
|
|
};
|
|
|
|
static struct FaceCount MaximumFan( GLUhalfEdge *eOrig );
|
|
static struct FaceCount MaximumStrip( GLUhalfEdge *eOrig );
|
|
|
|
static void RenderFan( GLUtesselator *tess, GLUhalfEdge *eStart, long size );
|
|
static void RenderStrip( GLUtesselator *tess, GLUhalfEdge *eStart, long size );
|
|
static void RenderTriangle( GLUtesselator *tess, GLUhalfEdge *eStart,
|
|
long size );
|
|
|
|
static void RenderMaximumFaceGroup( GLUtesselator *tess, GLUface *fOrig );
|
|
static void RenderLonelyTriangles( GLUtesselator *tess, GLUface *head );
|
|
|
|
|
|
|
|
/************************ Strips and Fans decomposition ******************/
|
|
|
|
/* __gl_renderMesh( tess, mesh ) takes a mesh and breaks it into triangle
|
|
* fans, strips, and separate triangles. A substantial effort is made
|
|
* to use as few rendering primitives as possible (ie. to make the fans
|
|
* and strips as large as possible).
|
|
*
|
|
* The rendering output is provided as callbacks (see the api).
|
|
*/
|
|
void __gl_renderMesh( GLUtesselator *tess, GLUmesh *mesh )
|
|
{
|
|
GLUface *f;
|
|
|
|
/* Make a list of separate triangles so we can render them all at once */
|
|
tess->lonelyTriList = NULL;
|
|
|
|
for( f = mesh->fHead.next; f != &mesh->fHead; f = f->next ) {
|
|
f->marked = FALSE;
|
|
}
|
|
for( f = mesh->fHead.next; f != &mesh->fHead; f = f->next ) {
|
|
|
|
/* We examine all faces in an arbitrary order. Whenever we find
|
|
* an unprocessed face F, we output a group of faces including F
|
|
* whose size is maximum.
|
|
*/
|
|
if( f->inside && ! f->marked ) {
|
|
RenderMaximumFaceGroup( tess, f );
|
|
assert( f->marked );
|
|
}
|
|
}
|
|
if( tess->lonelyTriList != NULL ) {
|
|
RenderLonelyTriangles( tess, tess->lonelyTriList );
|
|
tess->lonelyTriList = NULL;
|
|
}
|
|
}
|
|
|
|
|
|
static void RenderMaximumFaceGroup( GLUtesselator *tess, GLUface *fOrig )
|
|
{
|
|
/* We want to find the largest triangle fan or strip of unmarked faces
|
|
* which includes the given face fOrig. There are 3 possible fans
|
|
* passing through fOrig (one centered at each vertex), and 3 possible
|
|
* strips (one for each CCW permutation of the vertices). Our strategy
|
|
* is to try all of these, and take the primitive which uses the most
|
|
* triangles (a greedy approach).
|
|
*/
|
|
GLUhalfEdge *e = fOrig->anEdge;
|
|
struct FaceCount max, newFace;
|
|
|
|
max.size = 1;
|
|
max.eStart = e;
|
|
max.render = &RenderTriangle;
|
|
|
|
if( ! tess->flagBoundary ) {
|
|
newFace = MaximumFan( e ); if( newFace.size > max.size ) { max = newFace; }
|
|
newFace = MaximumFan( e->Lnext ); if( newFace.size > max.size ) { max = newFace; }
|
|
newFace = MaximumFan( e->Lprev ); if( newFace.size > max.size ) { max = newFace; }
|
|
|
|
newFace = MaximumStrip( e ); if( newFace.size > max.size ) { max = newFace; }
|
|
newFace = MaximumStrip( e->Lnext ); if( newFace.size > max.size ) { max = newFace; }
|
|
newFace = MaximumStrip( e->Lprev ); if( newFace.size > max.size ) { max = newFace; }
|
|
}
|
|
(*(max.render))( tess, max.eStart, max.size );
|
|
}
|
|
|
|
|
|
/* Macros which keep track of faces we have marked temporarily, and allow
|
|
* us to backtrack when necessary. With triangle fans, this is not
|
|
* really necessary, since the only awkward case is a loop of triangles
|
|
* around a single origin vertex. However with strips the situation is
|
|
* more complicated, and we need a general tracking method like the
|
|
* one here.
|
|
*/
|
|
#define Marked(f) (! (f)->inside || (f)->marked)
|
|
|
|
#define AddToTrail(f,t) ((f)->trail = (t), (t) = (f), (f)->marked = TRUE)
|
|
|
|
#define FreeTrail(t) do { \
|
|
while( (t) != NULL ) { \
|
|
(t)->marked = FALSE; t = (t)->trail; \
|
|
} \
|
|
} while(0) /* absorb trailing semicolon */
|
|
|
|
|
|
|
|
static struct FaceCount MaximumFan( GLUhalfEdge *eOrig )
|
|
{
|
|
/* eOrig->Lface is the face we want to render. We want to find the size
|
|
* of a maximal fan around eOrig->Org. To do this we just walk around
|
|
* the origin vertex as far as possible in both directions.
|
|
*/
|
|
struct FaceCount newFace = { 0, NULL, &RenderFan };
|
|
GLUface *trail = NULL;
|
|
GLUhalfEdge *e;
|
|
|
|
for( e = eOrig; ! Marked( e->Lface ); e = e->Onext ) {
|
|
AddToTrail( e->Lface, trail );
|
|
++newFace.size;
|
|
}
|
|
for( e = eOrig; ! Marked( e->Rface ); e = e->Oprev ) {
|
|
AddToTrail( e->Rface, trail );
|
|
++newFace.size;
|
|
}
|
|
newFace.eStart = e;
|
|
/*LINTED*/
|
|
FreeTrail( trail );
|
|
return newFace;
|
|
}
|
|
|
|
|
|
#define IsEven(n) (((n) & 1) == 0)
|
|
|
|
static struct FaceCount MaximumStrip( GLUhalfEdge *eOrig )
|
|
{
|
|
/* Here we are looking for a maximal strip that contains the vertices
|
|
* eOrig->Org, eOrig->Dst, eOrig->Lnext->Dst (in that order or the
|
|
* reverse, such that all triangles are oriented CCW).
|
|
*
|
|
* Again we walk forward and backward as far as possible. However for
|
|
* strips there is a twist: to get CCW orientations, there must be
|
|
* an *even* number of triangles in the strip on one side of eOrig.
|
|
* We walk the strip starting on a side with an even number of triangles;
|
|
* if both side have an odd number, we are forced to shorten one side.
|
|
*/
|
|
struct FaceCount newFace = { 0, NULL, &RenderStrip };
|
|
long headSize = 0, tailSize = 0;
|
|
GLUface *trail = NULL;
|
|
GLUhalfEdge *e, *eTail, *eHead;
|
|
|
|
for( e = eOrig; ! Marked( e->Lface ); ++tailSize, e = e->Onext ) {
|
|
AddToTrail( e->Lface, trail );
|
|
++tailSize;
|
|
e = e->Dprev;
|
|
if( Marked( e->Lface )) break;
|
|
AddToTrail( e->Lface, trail );
|
|
}
|
|
eTail = e;
|
|
|
|
for( e = eOrig; ! Marked( e->Rface ); ++headSize, e = e->Dnext ) {
|
|
AddToTrail( e->Rface, trail );
|
|
++headSize;
|
|
e = e->Oprev;
|
|
if( Marked( e->Rface )) break;
|
|
AddToTrail( e->Rface, trail );
|
|
}
|
|
eHead = e;
|
|
|
|
newFace.size = tailSize + headSize;
|
|
if( IsEven( tailSize )) {
|
|
newFace.eStart = eTail->Sym;
|
|
} else if( IsEven( headSize )) {
|
|
newFace.eStart = eHead;
|
|
} else {
|
|
/* Both sides have odd length, we must shorten one of them. In fact,
|
|
* we must start from eHead to guarantee inclusion of eOrig->Lface.
|
|
*/
|
|
--newFace.size;
|
|
newFace.eStart = eHead->Onext;
|
|
}
|
|
/*LINTED*/
|
|
FreeTrail( trail );
|
|
return newFace;
|
|
}
|
|
|
|
|
|
static void RenderTriangle( GLUtesselator *tess, GLUhalfEdge *e, long size )
|
|
{
|
|
/* Just add the triangle to a triangle list, so we can render all
|
|
* the separate triangles at once.
|
|
*/
|
|
assert( size == 1 );
|
|
AddToTrail( e->Lface, tess->lonelyTriList );
|
|
}
|
|
|
|
|
|
static void RenderLonelyTriangles( GLUtesselator *tess, GLUface *f )
|
|
{
|
|
/* Now we render all the separate triangles which could not be
|
|
* grouped into a triangle fan or strip.
|
|
*/
|
|
GLUhalfEdge *e;
|
|
int newState;
|
|
int edgeState = -1; /* force edge state output for first vertex */
|
|
|
|
CALL_BEGIN_OR_BEGIN_DATA( GL_TRIANGLES );
|
|
|
|
for( ; f != NULL; f = f->trail ) {
|
|
/* Loop once for each edge (there will always be 3 edges) */
|
|
|
|
e = f->anEdge;
|
|
do {
|
|
if( tess->flagBoundary ) {
|
|
/* Set the "edge state" to TRUE just before we output the
|
|
* first vertex of each edge on the polygon boundary.
|
|
*/
|
|
newState = ! e->Rface->inside;
|
|
if( edgeState != newState ) {
|
|
edgeState = newState;
|
|
CALL_EDGE_FLAG_OR_EDGE_FLAG_DATA( edgeState );
|
|
}
|
|
}
|
|
CALL_VERTEX_OR_VERTEX_DATA( e->Org->data );
|
|
|
|
e = e->Lnext;
|
|
} while( e != f->anEdge );
|
|
}
|
|
CALL_END_OR_END_DATA();
|
|
}
|
|
|
|
|
|
static void RenderFan( GLUtesselator *tess, GLUhalfEdge *e, long size )
|
|
{
|
|
/* Render as many CCW triangles as possible in a fan starting from
|
|
* edge "e". The fan *should* contain exactly "size" triangles
|
|
* (otherwise we've goofed up somewhere).
|
|
*/
|
|
CALL_BEGIN_OR_BEGIN_DATA( GL_TRIANGLE_FAN );
|
|
CALL_VERTEX_OR_VERTEX_DATA( e->Org->data );
|
|
CALL_VERTEX_OR_VERTEX_DATA( e->Dst->data );
|
|
|
|
while( ! Marked( e->Lface )) {
|
|
e->Lface->marked = TRUE;
|
|
--size;
|
|
e = e->Onext;
|
|
CALL_VERTEX_OR_VERTEX_DATA( e->Dst->data );
|
|
}
|
|
|
|
assert( size == 0 );
|
|
CALL_END_OR_END_DATA();
|
|
}
|
|
|
|
|
|
static void RenderStrip( GLUtesselator *tess, GLUhalfEdge *e, long size )
|
|
{
|
|
/* Render as many CCW triangles as possible in a strip starting from
|
|
* edge "e". The strip *should* contain exactly "size" triangles
|
|
* (otherwise we've goofed up somewhere).
|
|
*/
|
|
CALL_BEGIN_OR_BEGIN_DATA( GL_TRIANGLE_STRIP );
|
|
CALL_VERTEX_OR_VERTEX_DATA( e->Org->data );
|
|
CALL_VERTEX_OR_VERTEX_DATA( e->Dst->data );
|
|
|
|
while( ! Marked( e->Lface )) {
|
|
e->Lface->marked = TRUE;
|
|
--size;
|
|
e = e->Dprev;
|
|
CALL_VERTEX_OR_VERTEX_DATA( e->Org->data );
|
|
if( Marked( e->Lface )) break;
|
|
|
|
e->Lface->marked = TRUE;
|
|
--size;
|
|
e = e->Onext;
|
|
CALL_VERTEX_OR_VERTEX_DATA( e->Dst->data );
|
|
}
|
|
|
|
assert( size == 0 );
|
|
CALL_END_OR_END_DATA();
|
|
}
|
|
|
|
|
|
/************************ Boundary contour decomposition ******************/
|
|
|
|
/* __gl_renderBoundary( tess, mesh ) takes a mesh, and outputs one
|
|
* contour for each face marked "inside". The rendering output is
|
|
* provided as callbacks (see the api).
|
|
*/
|
|
void __gl_renderBoundary( GLUtesselator *tess, GLUmesh *mesh )
|
|
{
|
|
GLUface *f;
|
|
GLUhalfEdge *e;
|
|
|
|
for( f = mesh->fHead.next; f != &mesh->fHead; f = f->next ) {
|
|
if( f->inside ) {
|
|
CALL_BEGIN_OR_BEGIN_DATA( GL_LINE_LOOP );
|
|
e = f->anEdge;
|
|
do {
|
|
CALL_VERTEX_OR_VERTEX_DATA( e->Org->data );
|
|
e = e->Lnext;
|
|
} while( e != f->anEdge );
|
|
CALL_END_OR_END_DATA();
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/************************ Quick-and-dirty decomposition ******************/
|
|
|
|
#define SIGN_INCONSISTENT 2
|
|
|
|
static int ComputeNormal( GLUtesselator *tess, GLdouble norm[3], int check )
|
|
/*
|
|
* If check==FALSE, we compute the polygon normal and place it in norm[].
|
|
* If check==TRUE, we check that each triangle in the fan from v0 has a
|
|
* consistent orientation with respect to norm[]. If triangles are
|
|
* consistently oriented CCW, return 1; if CW, return -1; if all triangles
|
|
* are degenerate return 0; otherwise (no consistent orientation) return
|
|
* SIGN_INCONSISTENT.
|
|
*/
|
|
{
|
|
CachedVertex *v0 = tess->cache;
|
|
CachedVertex *vn = v0 + tess->cacheCount;
|
|
CachedVertex *vc;
|
|
GLdouble dot, xc, yc, zc, xp, yp, zp, n[3];
|
|
int sign = 0;
|
|
|
|
/* Find the polygon normal. It is important to get a reasonable
|
|
* normal even when the polygon is self-intersecting (eg. a bowtie).
|
|
* Otherwise, the computed normal could be very tiny, but perpendicular
|
|
* to the true plane of the polygon due to numerical noise. Then all
|
|
* the triangles would appear to be degenerate and we would incorrectly
|
|
* decompose the polygon as a fan (or simply not render it at all).
|
|
*
|
|
* We use a sum-of-triangles normal algorithm rather than the more
|
|
* efficient sum-of-trapezoids method (used in CheckOrientation()
|
|
* in normal.c). This lets us explicitly reverse the signed area
|
|
* of some triangles to get a reasonable normal in the self-intersecting
|
|
* case.
|
|
*/
|
|
if( ! check ) {
|
|
norm[0] = norm[1] = norm[2] = 0.0;
|
|
}
|
|
|
|
vc = v0 + 1;
|
|
xc = vc->coords[0] - v0->coords[0];
|
|
yc = vc->coords[1] - v0->coords[1];
|
|
zc = vc->coords[2] - v0->coords[2];
|
|
while( ++vc < vn ) {
|
|
xp = xc; yp = yc; zp = zc;
|
|
xc = vc->coords[0] - v0->coords[0];
|
|
yc = vc->coords[1] - v0->coords[1];
|
|
zc = vc->coords[2] - v0->coords[2];
|
|
|
|
/* Compute (vp - v0) cross (vc - v0) */
|
|
n[0] = yp*zc - zp*yc;
|
|
n[1] = zp*xc - xp*zc;
|
|
n[2] = xp*yc - yp*xc;
|
|
|
|
dot = n[0]*norm[0] + n[1]*norm[1] + n[2]*norm[2];
|
|
if( ! check ) {
|
|
/* Reverse the contribution of back-facing triangles to get
|
|
* a reasonable normal for self-intersecting polygons (see above)
|
|
*/
|
|
if( dot >= 0 ) {
|
|
norm[0] += n[0]; norm[1] += n[1]; norm[2] += n[2];
|
|
} else {
|
|
norm[0] -= n[0]; norm[1] -= n[1]; norm[2] -= n[2];
|
|
}
|
|
} else if( dot != 0 ) {
|
|
/* Check the new orientation for consistency with previous triangles */
|
|
if( dot > 0 ) {
|
|
if( sign < 0 ) return SIGN_INCONSISTENT;
|
|
sign = 1;
|
|
} else {
|
|
if( sign > 0 ) return SIGN_INCONSISTENT;
|
|
sign = -1;
|
|
}
|
|
}
|
|
}
|
|
return sign;
|
|
}
|
|
|
|
/* __gl_renderCache( tess ) takes a single contour and tries to render it
|
|
* as a triangle fan. This handles convex polygons, as well as some
|
|
* non-convex polygons if we get lucky.
|
|
*
|
|
* Returns TRUE if the polygon was successfully rendered. The rendering
|
|
* output is provided as callbacks (see the api).
|
|
*/
|
|
GLboolean __gl_renderCache( GLUtesselator *tess )
|
|
{
|
|
CachedVertex *v0 = tess->cache;
|
|
CachedVertex *vn = v0 + tess->cacheCount;
|
|
CachedVertex *vc;
|
|
GLdouble norm[3];
|
|
int sign;
|
|
|
|
if( tess->cacheCount < 3 ) {
|
|
/* Degenerate contour -- no output */
|
|
return TRUE;
|
|
}
|
|
|
|
norm[0] = tess->normal[0];
|
|
norm[1] = tess->normal[1];
|
|
norm[2] = tess->normal[2];
|
|
if( norm[0] == 0 && norm[1] == 0 && norm[2] == 0 ) {
|
|
ComputeNormal( tess, norm, FALSE );
|
|
}
|
|
|
|
sign = ComputeNormal( tess, norm, TRUE );
|
|
if( sign == SIGN_INCONSISTENT ) {
|
|
/* Fan triangles did not have a consistent orientation */
|
|
return FALSE;
|
|
}
|
|
if( sign == 0 ) {
|
|
/* All triangles were degenerate */
|
|
return TRUE;
|
|
}
|
|
|
|
/* Make sure we do the right thing for each winding rule */
|
|
switch( tess->windingRule ) {
|
|
case GLU_TESS_WINDING_ODD:
|
|
case GLU_TESS_WINDING_NONZERO:
|
|
break;
|
|
case GLU_TESS_WINDING_POSITIVE:
|
|
if( sign < 0 ) return TRUE;
|
|
break;
|
|
case GLU_TESS_WINDING_NEGATIVE:
|
|
if( sign > 0 ) return TRUE;
|
|
break;
|
|
case GLU_TESS_WINDING_ABS_GEQ_TWO:
|
|
return TRUE;
|
|
}
|
|
|
|
CALL_BEGIN_OR_BEGIN_DATA( tess->boundaryOnly ? GL_LINE_LOOP
|
|
: (tess->cacheCount > 3) ? GL_TRIANGLE_FAN
|
|
: GL_TRIANGLES );
|
|
|
|
CALL_VERTEX_OR_VERTEX_DATA( v0->data );
|
|
if( sign > 0 ) {
|
|
for( vc = v0+1; vc < vn; ++vc ) {
|
|
CALL_VERTEX_OR_VERTEX_DATA( vc->data );
|
|
}
|
|
} else {
|
|
for( vc = vn-1; vc > v0; --vc ) {
|
|
CALL_VERTEX_OR_VERTEX_DATA( vc->data );
|
|
}
|
|
}
|
|
CALL_END_OR_END_DATA();
|
|
return TRUE;
|
|
}
|