1 files changed, 126 insertions, 0 deletions
diff --git a/progs/redbook/unproject.c b/progs/redbook/unproject.c
new file mode 100644
index 0000000000..134c361bac
--- /dev/null
+++ b/progs/redbook/unproject.c
@@ -0,0 +1,126 @@
+/*
+ * 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+ * Unpublished-- rights reserved under the copyright laws of the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.
+ */
+
+/*
+ *  unproject.c
+ *  When the left mouse button is pressed, this program 
+ *  reads the mouse position and determines two 3D points 
+ *  from which it was transformed.  Very little is displayed.
+ */
+#include <GL/glut.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+void display(void)
+{
+   glClear(GL_COLOR_BUFFER_BIT);
+   glFlush();
+}
+
+/* Change these values for a different transformation  */
+void reshape(int w, int h)
+{
+   glViewport (0, 0, (GLsizei) w, (GLsizei) h);
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+   gluPerspective (45.0, (GLfloat) w/(GLfloat) h, 1.0, 100.0);
+   glMatrixMode(GL_MODELVIEW);
+   glLoadIdentity();
+}
+
+void mouse(int button, int state, int x, int y) 
+{
+   GLint viewport[4];
+   GLdouble mvmatrix[16], projmatrix[16];
+   GLint realy;  /*  OpenGL y coordinate position  */
+   GLdouble wx, wy, wz;  /*  returned world x, y, z coords  */
+
+   switch (button) {
+      case GLUT_LEFT_BUTTON:
+         if (state == GLUT_DOWN) {
+            glGetIntegerv (GL_VIEWPORT, viewport);
+            glGetDoublev (GL_MODELVIEW_MATRIX, mvmatrix);
+            glGetDoublev (GL_PROJECTION_MATRIX, projmatrix);
+/*  note viewport[3] is height of window in pixels  */
+            realy = viewport[3] - (GLint) y - 1;
+            printf ("Coordinates at cursor are (%4d, %4d)\n", x, realy);
+            gluUnProject ((GLdouble) x, (GLdouble) realy, 0.0, 
+               mvmatrix, projmatrix, viewport, &wx, &wy, &wz); 
+            printf ("World coords at z=0.0 are (%f, %f, %f)\n", 
+               wx, wy, wz);
+            gluUnProject ((GLdouble) x, (GLdouble) realy, 1.0, 
+               mvmatrix, projmatrix, viewport, &wx, &wy, &wz); 
+            printf ("World coords at z=1.0 are (%f, %f, %f)\n", 
+               wx, wy, wz);
+         }
+         break;
+      case GLUT_RIGHT_BUTTON:
+         if (state == GLUT_DOWN)
+            exit(0);
+         break;
+      default:
+         break;
+   }
+}
+
+/* ARGSUSED1 */
+void keyboard(unsigned char key, int x, int y)
+{
+   switch (key) {
+      case 27:
+         exit(0);
+         break;
+   }
+}
+   
+/* 
+ *  Open window, register input callback functions
+ */
+int main(int argc, char** argv)
+{
+   glutInit(&argc, argv);
+   glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
+   glutInitWindowSize (500, 500); 
+   glutInitWindowPosition (100, 100);
+   glutCreateWindow (argv[0]);
+   glutDisplayFunc(display); 
+   glutReshapeFunc(reshape); 
+   glutKeyboardFunc (keyboard);
+   glutMouseFunc(mouse);
+   glutMainLoop();
+   return 0;
+}