Fixed arbitrary polygon winding problem here so all tristrips are passed

to runtime simulator with a consistant counter clockwise winding.

diff --git a/FixObj/Makefile.in b/FixObj/Makefile.in
index b42166e35a5b37a16f51582d454bd7c60ec29354..6f4875315ba67762d6954ab11e21566529da513e 100644 (file)
--- a/FixObj/Makefile.in
+++ b/FixObj/Makefile.in
@@ -347,8 +347,9 @@ INCLUDES += -I$(top_builddir) -I$(top_builddir)/Lib
 
 #---------------------------------------------------------------------------
 # $Log$
-# Revision 1.12  1998/05/16 13:11:25  curt
-# Fixed an off by one error in node, normal, and face counters.
+# Revision 1.13  1998/05/20 20:55:18  curt
+# Fixed arbitrary polygon winding problem here so all tristrips are passed
+# to runtime simulator with a consistant counter clockwise winding.
 #
 # Revision 1.4  1998/04/24 00:44:05  curt
 # Added zlib support.

diff --git a/FixObj/obj.c b/FixObj/obj.c
index b06c0d6b054a1c3c80bd067865159d2ac004183f..77e0d8e137df0d1b490a767ea088b4d19e90c8f1 100644 (file)
--- a/FixObj/obj.c
+++ b/FixObj/obj.c
@@ -71,13 +71,105 @@ void list_add(int *list, int *list_ptr, int node) {
 }
 
 
+/* fix the cw list and append to ccw_list */
+void fix_cw_list(int *list, int list_ptr) {
+    int i, j, len;
+
+    if ( list_ptr < 3 ) {
+       printf("List is empty ... skipping\n");
+       return;
+    }
+
+    printf("Fixing cw list, size = %d\n", list_ptr);
+
+    i = 0;
+    while ( i < list_ptr ) { 
+       /* do next strip */
+
+       /* find length */
+       len = 0;
+       /* scan rest of strip (until -1) */
+       while ( ((i+len) < list_ptr) && (list[i+len] != -1) ) { 
+           // printf("len = %d item = %d\n", len, list[i+len] );
+           len++;
+       }
+       // printf("          Final length = %d\n", len);
+
+       if ( (len % 2) != 0 ) {
+           /* if length is odd, just reverse order of nodes to reverse
+              winding */
+           if ( ccw_list_ptr ) {
+               list_add(ccw_list, &ccw_list_ptr, -1);
+           }
+           for ( j = i + len - 1; j >= i; j-- ) {
+               // printf(" odd -> item = %d\n", list[j] );
+               list_add(ccw_list, &ccw_list_ptr, list[j]);
+           }
+       } else {
+           /* if length is even, reverse order of (n-1) nodes to
+              reverse winding, and create an orphan triangle for the
+              last "nth" node */
+           if ( ccw_list_ptr ) {
+               list_add(ccw_list, &ccw_list_ptr, -1);
+           }
+           for ( j = i + len - 2; j >= i; j-- ) {
+               // printf(" even -> item = %d\n", list[j] );
+               list_add(ccw_list, &ccw_list_ptr, list[j]);
+           }
+
+           // printf(" even bonus -> item = %d\n", list[i + len - 1] );
+           // printf(" even bonus -> item = %d\n", list[i + len - 2] );
+           // printf(" even bonus -> item = %d\n", list[i + len - 3] );
+           list_add(ccw_list, &ccw_list_ptr, -1);
+           list_add(ccw_list, &ccw_list_ptr, list[i + len - 3]);
+           list_add(ccw_list, &ccw_list_ptr, list[i + len - 2]);
+           list_add(ccw_list, &ccw_list_ptr, list[i + len - 1]);
+       }
+
+       i += len + 1;
+    }
+}
+
+
+// Calculate distance between (0,0,0) and the specified point
+static double calc_dist(double x, double y, double z) {
+    return ( sqrt(x*x + y*y + z*z) );
+}
+
+
+void dump_global_bounds( void ) {
+    double dist, radius;
+    int i;
+
+    radius = 0.0;
+
+    fprintf(out, "\n");
+
+    for ( i = 1; i < ncount; i++ ) {
+
+       dist = calc_dist(nodes[i][0] - refx, nodes[i][1] - refy, 
+                        nodes[i][2] - refz);
+       // printf("node = %.2f %.2f %.2f dist = %.2f\n", 
+        //        nodes[i][0], nodes[i][1], nodes[i][2],
+       //        dist);
+
+       if ( dist > radius ) {
+           radius = dist;
+       }
+
+    }
+
+    fprintf(out, "gb %.4f %.4f %.4f %.2f\n", refx, refy, refz, radius);
+}
+
+
 /* dump nodes */
 void dump_nodes( void ) {
     int i;
 
     fprintf(out, "\n");
-    for ( i = 1; i <= ncount; i++ ) {
-       fprintf(out, "v %.4lf %.4lf %.4lf\n",
+    for ( i = 1; i < ncount; i++ ) {
+       fprintf(out, "v %.4f %.4f %.4f\n",
                nodes[i][0] - refx, nodes[i][1] - refy, nodes[i][2] - refz);
     }
 }
@@ -88,8 +180,8 @@ void dump_normals( void ) {
     int i;
 
     fprintf(out, "\n");
-    for ( i = 1; i <= vncount; i++ ) {
-       fprintf(out, "vn %.4lf %.4lf %.4lf\n", 
+    for ( i = 1; i < vncount; i++ ) {
+       fprintf(out, "vn %.4f %.4f %.4f\n", 
                normals[i][0], normals[i][1], normals[i][2]);
     }
 }
@@ -100,7 +192,7 @@ void dump_faces( void ) {
     int i;
 
     fprintf(out, "\n");
-    for ( i = 1; i <= fcount; i++ ) {
+    for ( i = 1; i < fcount; i++ ) {
        fprintf(out, "f %d %d %d\n", 
                faces[i][0], faces[i][1], faces[i][2]);
     }
@@ -122,6 +214,12 @@ void dump_list(int *list, int list_ptr) {
     while ( i < list_ptr ) { 
        /* do next strip */
 
+       if ( (i % 2) == 0 ) {
+           fprintf(out, "\nusemtl desert1\n");
+       } else {
+           fprintf(out, "\nusemtl desert2\n");
+       }
+
        /* dump header */
        fprintf(out, "t %d %d %d\n", list[i], list[i+1], list[i+2]);
        /* printf("t %d %d %d\n", list[i], list[i+1], list[i+2]); */
@@ -202,9 +300,9 @@ void obj_fix(char *infile, char *outfile) {
     /* I start counting at one because that is how the triangle
        program refers to nodes and normals */
     first = 1;
-    ncount = 0;
-    vncount = 0;
-    fcount = 0;
+    ncount = 1;
+    vncount = 1;
+    fcount = 1;
 
     printf("Reading file:  %s\n", infile);
 
@@ -361,28 +459,31 @@ void obj_fix(char *infile, char *outfile) {
     refy = (ymin + ymax) / 2.0;
     refz = (zmin + zmax) / 2.0;
 
-    fprintf(out, "\n");
-    fprintf(out, "ref %.2f %.2f %.2f\n", refx, refy, refz);    
+    /* convert the cw_list to ccw add append to ccw_list */
+    fix_cw_list(cw_list, cw_list_ptr);
 
+    dump_global_bounds();
     dump_nodes();
     dump_normals();
-    dump_faces();
+    if ( fcount > 1 ) {
+       dump_faces();
+    }
 
-    fprintf(out, "winding ccw\n");
     dump_list(ccw_list, ccw_list_ptr);
 
-    fprintf(out, "winding cw\n");
-    dump_list(cw_list, cw_list_ptr);
-
     fclose(in);
     fclose(out);
 }
 
 
 /* $Log$
-/* Revision 1.12  1998/05/16 13:11:26  curt
-/* Fixed an off by one error in node, normal, and face counters.
+/* Revision 1.13  1998/05/20 20:55:19  curt
+/* Fixed arbitrary polygon winding problem here so all tristrips are passed
+/* to runtime simulator with a consistant counter clockwise winding.
 /*
+ * Revision 1.12  1998/05/16 13:11:26  curt
+ * Fixed an off by one error in node, normal, and face counters.
+ *
  * Revision 1.11  1998/04/27 15:59:24  curt
  * Fixed an off by one error.
  *