svn merge ^/branches/released . --username marha

1 files changed, 253 insertions, 0 deletions

diff --git a/mesalib/src/glu/sgi/libtess/normal.c b/mesalib/src/glu/sgi/libtess/normal.c
new file mode 100644
index 000000000..0a2494be3
--- /dev/null
+++ b/mesalib/src/glu/sgi/libtess/normal.c
@@ -0,0 +1,253 @@
+/*
+ * 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 "gluos.h"
+#include "mesh.h"
+#include "tess.h"
+#include "normal.h"
+#include <math.h>
+#include <assert.h>
+
+#define TRUE 1
+#define FALSE 0
+
+#define Dot(u,v)	(u[0]*v[0] + u[1]*v[1] + u[2]*v[2])
+
+#if 0
+static void Normalize( GLdouble v[3] )
+{
+  GLdouble len = v[0]*v[0] + v[1]*v[1] + v[2]*v[2];
+
+  assert( len > 0 );
+  len = sqrt( len );
+  v[0] /= len;
+  v[1] /= len;
+  v[2] /= len;
+}
+#endif
+
+#undef	ABS
+#define ABS(x)	((x) < 0 ? -(x) : (x))
+
+static int LongAxis( GLdouble v[3] )
+{
+  int i = 0;
+
+  if( ABS(v[1]) > ABS(v[0]) ) { i = 1; }
+  if( ABS(v[2]) > ABS(v[i]) ) { i = 2; }
+  return i;
+}
+
+static void ComputeNormal( GLUtesselator *tess, GLdouble norm[3] )
+{
+  GLUvertex *v, *v1, *v2;
+  GLdouble c, tLen2, maxLen2;
+  GLdouble maxVal[3], minVal[3], d1[3], d2[3], tNorm[3];
+  GLUvertex *maxVert[3], *minVert[3];
+  GLUvertex *vHead = &tess->mesh->vHead;
+  int i;
+
+  maxVal[0] = maxVal[1] = maxVal[2] = -2 * GLU_TESS_MAX_COORD;
+  minVal[0] = minVal[1] = minVal[2] = 2 * GLU_TESS_MAX_COORD;
+
+  for( v = vHead->next; v != vHead; v = v->next ) {
+    for( i = 0; i < 3; ++i ) {
+      c = v->coords[i];
+      if( c < minVal[i] ) { minVal[i] = c; minVert[i] = v; }
+      if( c > maxVal[i] ) { maxVal[i] = c; maxVert[i] = v; }
+    }
+  }
+
+  /* Find two vertices separated by at least 1/sqrt(3) of the maximum
+   * distance between any two vertices
+   */
+  i = 0;
+  if( maxVal[1] - minVal[1] > maxVal[0] - minVal[0] ) { i = 1; }
+  if( maxVal[2] - minVal[2] > maxVal[i] - minVal[i] ) { i = 2; }
+  if( minVal[i] >= maxVal[i] ) {
+    /* All vertices are the same -- normal doesn't matter */
+    norm[0] = 0; norm[1] = 0; norm[2] = 1;
+    return;
+  }
+
+  /* Look for a third vertex which forms the triangle with maximum area
+   * (Length of normal == twice the triangle area)
+   */
+  maxLen2 = 0;
+  v1 = minVert[i];
+  v2 = maxVert[i];
+  d1[0] = v1->coords[0] - v2->coords[0];
+  d1[1] = v1->coords[1] - v2->coords[1];
+  d1[2] = v1->coords[2] - v2->coords[2];
+  for( v = vHead->next; v != vHead; v = v->next ) {
+    d2[0] = v->coords[0] - v2->coords[0];
+    d2[1] = v->coords[1] - v2->coords[1];
+    d2[2] = v->coords[2] - v2->coords[2];
+    tNorm[0] = d1[1]*d2[2] - d1[2]*d2[1];
+    tNorm[1] = d1[2]*d2[0] - d1[0]*d2[2];
+    tNorm[2] = d1[0]*d2[1] - d1[1]*d2[0];
+    tLen2 = tNorm[0]*tNorm[0] + tNorm[1]*tNorm[1] + tNorm[2]*tNorm[2];
+    if( tLen2 > maxLen2 ) {
+      maxLen2 = tLen2;
+      norm[0] = tNorm[0];
+      norm[1] = tNorm[1];
+      norm[2] = tNorm[2];
+    }
+  }
+
+  if( maxLen2 <= 0 ) {
+    /* All points lie on a single line -- any decent normal will do */
+    norm[0] = norm[1] = norm[2] = 0;
+    norm[LongAxis(d1)] = 1;
+  }
+}
+
+
+static void CheckOrientation( GLUtesselator *tess )
+{
+  GLdouble area;
+  GLUface *f, *fHead = &tess->mesh->fHead;
+  GLUvertex *v, *vHead = &tess->mesh->vHead;
+  GLUhalfEdge *e;
+
+  /* When we compute the normal automatically, we choose the orientation
+   * so that the the sum of the signed areas of all contours is non-negative.
+   */
+  area = 0;
+  for( f = fHead->next; f != fHead; f = f->next ) {
+    e = f->anEdge;
+    if( e->winding <= 0 ) continue;
+    do {
+      area += (e->Org->s - e->Dst->s) * (e->Org->t + e->Dst->t);
+      e = e->Lnext;
+    } while( e != f->anEdge );
+  }
+  if( area < 0 ) {
+    /* Reverse the orientation by flipping all the t-coordinates */
+    for( v = vHead->next; v != vHead; v = v->next ) {
+      v->t = - v->t;
+    }
+    tess->tUnit[0] = - tess->tUnit[0];
+    tess->tUnit[1] = - tess->tUnit[1];
+    tess->tUnit[2] = - tess->tUnit[2];
+  }
+}
+
+#ifdef FOR_TRITE_TEST_PROGRAM
+#include <stdlib.h>
+extern int RandomSweep;
+#define S_UNIT_X	(RandomSweep ? (2*drand48()-1) : 1.0)
+#define S_UNIT_Y	(RandomSweep ? (2*drand48()-1) : 0.0)
+#else
+#if defined(SLANTED_SWEEP)
+/* The "feature merging" is not intended to be complete.  There are
+ * special cases where edges are nearly parallel to the sweep line
+ * which are not implemented.  The algorithm should still behave
+ * robustly (ie. produce a reasonable tesselation) in the presence
+ * of such edges, however it may miss features which could have been
+ * merged.  We could minimize this effect by choosing the sweep line
+ * direction to be something unusual (ie. not parallel to one of the
+ * coordinate axes).
+ */
+#define S_UNIT_X	0.50941539564955385	/* Pre-normalized */
+#define S_UNIT_Y	0.86052074622010633
+#else
+#define S_UNIT_X	1.0
+#define S_UNIT_Y	0.0
+#endif
+#endif
+
+/* Determine the polygon normal and project vertices onto the plane
+ * of the polygon.
+ */
+void __gl_projectPolygon( GLUtesselator *tess )
+{
+  GLUvertex *v, *vHead = &tess->mesh->vHead;
+  GLdouble norm[3];
+  GLdouble *sUnit, *tUnit;
+  int i, computedNormal = FALSE;
+
+  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 );
+    computedNormal = TRUE;
+  }
+  sUnit = tess->sUnit;
+  tUnit = tess->tUnit;
+  i = LongAxis( norm );
+
+#if defined(FOR_TRITE_TEST_PROGRAM) || defined(TRUE_PROJECT)
+  /* Choose the initial sUnit vector to be approximately perpendicular
+   * to the normal.
+   */
+  Normalize( norm );
+
+  sUnit[i] = 0;
+  sUnit[(i+1)%3] = S_UNIT_X;
+  sUnit[(i+2)%3] = S_UNIT_Y;
+
+  /* Now make it exactly perpendicular */
+  w = Dot( sUnit, norm );
+  sUnit[0] -= w * norm[0];
+  sUnit[1] -= w * norm[1];
+  sUnit[2] -= w * norm[2];
+  Normalize( sUnit );
+
+  /* Choose tUnit so that (sUnit,tUnit,norm) form a right-handed frame */
+  tUnit[0] = norm[1]*sUnit[2] - norm[2]*sUnit[1];
+  tUnit[1] = norm[2]*sUnit[0] - norm[0]*sUnit[2];
+  tUnit[2] = norm[0]*sUnit[1] - norm[1]*sUnit[0];
+  Normalize( tUnit );
+#else
+  /* Project perpendicular to a coordinate axis -- better numerically */
+  sUnit[i] = 0;
+  sUnit[(i+1)%3] = S_UNIT_X;
+  sUnit[(i+2)%3] = S_UNIT_Y;
+
+  tUnit[i] = 0;
+  tUnit[(i+1)%3] = (norm[i] > 0) ? -S_UNIT_Y : S_UNIT_Y;
+  tUnit[(i+2)%3] = (norm[i] > 0) ? S_UNIT_X : -S_UNIT_X;
+#endif
+
+  /* Project the vertices onto the sweep plane */
+  for( v = vHead->next; v != vHead; v = v->next ) {
+    v->s = Dot( v->coords, sUnit );
+    v->t = Dot( v->coords, tUnit );
+  }
+  if( computedNormal ) {
+    CheckOrientation( tess );
+  }
+}