1 files changed, 222 insertions, 0 deletions
diff --git a/progs/redbook/select.c b/progs/redbook/select.c
new file mode 100644
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--- /dev/null
+++ b/progs/redbook/select.c
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+/*
+ * Copyright (c) 1993-1997, Silicon Graphics, Inc.
+ * ALL RIGHTS RESERVED 
+ * Permission to use, copy, modify, and distribute this software for 
+ * any purpose and without fee is hereby granted, provided that the above
+ * copyright notice appear in all copies and that both the copyright notice
+ * and this permission notice appear in supporting documentation, and that 
+ * the name of Silicon Graphics, Inc. not be used in advertising
+ * or publicity pertaining to distribution of the software without specific,
+ * written prior permission. 
+ *
+ * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
+ * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
+ * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
+ * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
+ * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
+ * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
+ * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
+ * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
+ * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
+ * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
+ * 
+ * US Government Users Restricted Rights 
+ * Use, duplication, or disclosure by the Government is subject to
+ * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
+ * (c)(1)(ii) of the Rights in Technical Data and Computer Software
+ * clause at DFARS 252.227-7013 and/or in similar or successor
+ * clauses in the FAR or the DOD or NASA FAR Supplement.
+ * Unpublished-- rights reserved under the copyright laws of the
+ * United States.  Contractor/manufacturer is Silicon Graphics,
+ * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
+ *
+ * OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
+ */
+
+/*
+ * select.c
+ * This is an illustration of the selection mode and 
+ * name stack, which detects whether objects which collide 
+ * with a viewing volume.  First, four triangles and a 
+ * rectangular box representing a viewing volume are drawn 
+ * (drawScene routine).  The green triangle and yellow 
+ * triangles appear to lie within the viewing volume, but 
+ * the red triangle appears to lie outside it.  Then the 
+ * selection mode is entered (selectObjects routine).  
+ * Drawing to the screen ceases.  To see if any collisions 
+ * occur, the four triangles are called.  In this example, 
+ * the green triangle causes one hit with the name 1, and 
+ * the yellow triangles cause one hit with the name 3.
+ */
+#include <GL/glut.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+/* draw a triangle with vertices at (x1, y1), (x2, y2) 
+ * and (x3, y3) at z units away from the origin.
+ */
+void drawTriangle (GLfloat x1, GLfloat y1, GLfloat x2, 
+    GLfloat y2, GLfloat x3, GLfloat y3, GLfloat z)
+{
+   glBegin (GL_TRIANGLES);
+   glVertex3f (x1, y1, z);
+   glVertex3f (x2, y2, z);
+   glVertex3f (x3, y3, z);
+   glEnd ();
+}
+
+/* draw a rectangular box with these outer x, y, and z values */
+void drawViewVolume (GLfloat x1, GLfloat x2, GLfloat y1, 
+                     GLfloat y2, GLfloat z1, GLfloat z2)
+{
+   glColor3f (1.0, 1.0, 1.0);
+   glBegin (GL_LINE_LOOP);
+   glVertex3f (x1, y1, -z1);
+   glVertex3f (x2, y1, -z1);
+   glVertex3f (x2, y2, -z1);
+   glVertex3f (x1, y2, -z1);
+   glEnd ();
+
+   glBegin (GL_LINE_LOOP);
+   glVertex3f (x1, y1, -z2);
+   glVertex3f (x2, y1, -z2);
+   glVertex3f (x2, y2, -z2);
+   glVertex3f (x1, y2, -z2);
+   glEnd ();
+
+   glBegin (GL_LINES);	/*  4 lines	*/
+   glVertex3f (x1, y1, -z1);
+   glVertex3f (x1, y1, -z2);
+   glVertex3f (x1, y2, -z1);
+   glVertex3f (x1, y2, -z2);
+   glVertex3f (x2, y1, -z1);
+   glVertex3f (x2, y1, -z2);
+   glVertex3f (x2, y2, -z1);
+   glVertex3f (x2, y2, -z2);
+   glEnd ();
+}
+
+/* drawScene draws 4 triangles and a wire frame
+ * which represents the viewing volume.
+ */
+void drawScene (void)
+{
+   glMatrixMode (GL_PROJECTION);
+   glLoadIdentity ();
+   gluPerspective (40.0, 4.0/3.0, 1.0, 100.0);
+
+   glMatrixMode (GL_MODELVIEW);
+   glLoadIdentity ();
+   gluLookAt (7.5, 7.5, 12.5, 2.5, 2.5, -5.0, 0.0, 1.0, 0.0);
+   glColor3f (0.0, 1.0, 0.0);	/*  green triangle	*/
+   drawTriangle (2.0, 2.0, 3.0, 2.0, 2.5, 3.0, -5.0);
+   glColor3f (1.0, 0.0, 0.0);	/*  red triangle	*/
+   drawTriangle (2.0, 7.0, 3.0, 7.0, 2.5, 8.0, -5.0);
+   glColor3f (1.0, 1.0, 0.0);	/*  yellow triangles	*/
+   drawTriangle (2.0, 2.0, 3.0, 2.0, 2.5, 3.0, 0.0);
+   drawTriangle (2.0, 2.0, 3.0, 2.0, 2.5, 3.0, -10.0);
+   drawViewVolume (0.0, 5.0, 0.0, 5.0, 0.0, 10.0);
+}
+
+/* processHits prints out the contents of the selection array
+ */
+void processHits (GLint hits, GLuint buffer[])
+{
+   GLint i;
+   GLuint j, names, *ptr;
+
+   printf ("hits = %d\n", hits);
+   ptr = (GLuint *) buffer;
+   for (i = 0; i < hits; i++) {	/*  for each hit  */
+      names = *ptr;
+      printf (" number of names for hit = %d\n", names); ptr++;
+      printf("  z1 is %g;", (float) *ptr/0x7fffffff); ptr++;
+      printf(" z2 is %g\n", (float) *ptr/0x7fffffff); ptr++;
+      printf ("   the name is ");
+      for (j = 0; j < names; j++) {	/*  for each name */
+         printf ("%d ", *ptr); ptr++;
+      }
+      printf ("\n");
+   }
+}
+
+/* selectObjects "draws" the triangles in selection mode, 
+ * assigning names for the triangles.  Note that the third
+ * and fourth triangles share one name, so that if either 
+ * or both triangles intersects the viewing/clipping volume, 
+ * only one hit will be registered.
+ */
+#define BUFSIZE 512
+
+void selectObjects(void)
+{
+   GLuint selectBuf[BUFSIZE];
+   GLint hits;
+
+   glSelectBuffer (BUFSIZE, selectBuf);
+   (void) glRenderMode (GL_SELECT);
+
+   glInitNames();
+   glPushName(0);
+
+   glPushMatrix ();
+   glMatrixMode (GL_PROJECTION);
+   glLoadIdentity ();
+   glOrtho (0.0, 5.0, 0.0, 5.0, 0.0, 10.0);
+   glMatrixMode (GL_MODELVIEW);
+   glLoadIdentity ();
+   glLoadName(1);
+   drawTriangle (2.0, 2.0, 3.0, 2.0, 2.5, 3.0, -5.0);
+   glLoadName(2);
+   drawTriangle (2.0, 7.0, 3.0, 7.0, 2.5, 8.0, -5.0);
+   glLoadName(3);
+   drawTriangle (2.0, 2.0, 3.0, 2.0, 2.5, 3.0, 0.0);
+   drawTriangle (2.0, 2.0, 3.0, 2.0, 2.5, 3.0, -10.0);
+   glPopMatrix ();
+   glFlush ();
+
+   hits = glRenderMode (GL_RENDER);
+   processHits (hits, selectBuf);
+} 
+
+void init (void) 
+{
+   glEnable(GL_DEPTH_TEST);
+   glShadeModel(GL_FLAT);
+}
+
+void display(void)
+{
+   glClearColor (0.0, 0.0, 0.0, 0.0);
+   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+   drawScene ();
+   selectObjects ();
+   glFlush();
+}
+
+/* ARGSUSED1 */
+void keyboard(unsigned char key, int x, int y)
+{
+   switch (key) {
+      case 27:
+         exit(0);
+         break;
+   }
+}
+
+/*  Main Loop  */
+int main(int argc, char** argv)
+{
+   glutInit(&argc, argv);
+   glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
+   glutInitWindowSize (200, 200);
+   glutInitWindowPosition (100, 100);
+   glutCreateWindow (argv[0]);
+   init();
+   glutDisplayFunc(display);
+   glutKeyboardFunc(keyboard);
+   glutMainLoop();
+   return 0; 
+}