+void
+renderList (const struct gllist *list, int wire_p)
+{
+ while (list)
+ {
+ if (!wire_p || list->primitive == GL_LINES ||
+ list->primitive == GL_POINTS)
+ {
+ glInterleavedArrays (list->format, 0, list->data);
+ glDrawArrays (list->primitive, 0, list->points);
+ }
+ else
+ {
+ /* For wireframe, do it the hard way: treat every tuple of
+ points as its own line loop.
+ */
+ const GLfloat *p = (GLfloat *) list->data;
+ int i, j, tick, skip, stride;
+
+ switch (list->primitive) {
+ case GL_QUADS: tick = 4; break;
+ case GL_TRIANGLES: tick = 3; break;
+ default: abort(); break; /* write me */
+ }
+
+ switch (list->format) {
+ case GL_C3F_V3F: case GL_N3F_V3F: skip = 3; stride = 6; break;
+ default: abort(); break; /* write me */
+ }
+
+ glBegin (GL_LINE_LOOP);
+ for (i = 0, j = skip;
+ i < list->points;
+ i++, j += stride)
+ {
+ if (i && !(i % tick))
+ {
+ glEnd();
+ glBegin (GL_LINE_LOOP);
+ }
+ glVertex3f (p[j], p[j+1], p[j+2]);
+ }
+ glEnd();
+ }
+ list = list->next;
+ }
+}
+
+
+void
+renderListNormals (const struct gllist *list, GLfloat length, int faces_p)
+{
+ while (list)
+ {
+ const GLfloat *p = (GLfloat *) list->data;
+ int i, j, tick, skip, stride;
+ GLfloat v[3], n[3];
+
+ if (list->primitive == GL_LINES) continue;
+
+ if (! faces_p)
+ tick = 1;
+ else
+ switch (list->primitive) {
+ case GL_QUADS: tick = 4; break;
+ case GL_TRIANGLES: tick = 3; break;
+ default: abort(); break; /* write me */
+ }
+
+ switch (list->format) {
+ case GL_N3F_V3F: skip = 0; stride = 6; break;
+ case GL_C3F_V3F: continue; break;
+ default: abort(); break; /* write me */
+ }
+
+ v[0] = v[1] = v[2] = 0;
+ n[0] = n[1] = n[2] = 0;
+
+ for (i = 0, j = skip;
+ i <= list->points;
+ i++, j += stride)
+ {
+ if (i && !(i % tick))
+ {
+ n[0] /= tick;
+ n[1] /= tick;
+ n[2] /= tick;
+ v[0] /= tick;
+ v[1] /= tick;
+ v[2] /= tick;
+ glPushMatrix();
+ glTranslatef (v[0], v[1], v[2]);
+ glScalef (length, length, length);
+ glBegin (GL_LINES);
+ glVertex3f (0, 0, 0);
+ glVertex3f (n[0], n[1], n[2]);
+ glEnd();
+ glPopMatrix();
+ v[0] = v[1] = v[2] = 0;
+ n[0] = n[1] = n[2] = 0;
+ }
+
+ if (i == list->points) break;
+ n[0] += p[j];
+ n[1] += p[j+1];
+ n[2] += p[j+2];
+ v[0] += p[j+3];
+ v[1] += p[j+4];
+ v[2] += p[j+5];
+
+ }
+ list = list->next;
+ }