Initial revision

1 files changed, 197 insertions, 0 deletions

diff --git a/progs/redbook/picksquare.c b/progs/redbook/picksquare.c
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+++ b/progs/redbook/picksquare.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+ * Unpublished-- rights reserved under the copyright laws of the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.
+ */
+
+/*
+ * picksquare.c
+ * Use of multiple names and picking are demonstrated.  
+ * A 3x3 grid of squares is drawn.  When the left mouse 
+ * button is pressed, all squares under the cursor position 
+ * have their color changed.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <GL/glut.h>
+
+int board[3][3];   /*  amount of color for each square	*/
+
+/*  Clear color value for every square on the board   */
+void init(void)
+{
+   int i, j;
+   for (i = 0; i < 3; i++) 
+      for (j = 0; j < 3; j ++)
+         board[i][j] = 0;
+   glClearColor (0.0, 0.0, 0.0, 0.0);
+}
+
+/*  The nine squares are drawn.  In selection mode, each 
+ *  square is given two names:  one for the row and the 
+ *  other for the column on the grid.  The color of each 
+ *  square is determined by its position on the grid, and 
+ *  the value in the board[][] array.
+ */
+void drawSquares(GLenum mode)
+{
+   GLuint i, j;
+   for (i = 0; i < 3; i++) {
+      if (mode == GL_SELECT)
+         glLoadName (i);
+      for (j = 0; j < 3; j ++) {
+         if (mode == GL_SELECT)
+            glPushName (j);
+         glColor3f ((GLfloat) i/3.0, (GLfloat) j/3.0, 
+                    (GLfloat) board[i][j]/3.0);
+         glRecti (i, j, i+1, j+1);
+         if (mode == GL_SELECT)
+            glPopName ();
+      }
+   }
+}
+
+/*  processHits prints out the contents of the 
+ *  selection array.
+ */
+void processHits (GLint hits, GLuint buffer[])
+{
+   unsigned int i, j;
+   GLuint ii, jj, 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 this hit = %d\n", names); ptr++;
+      printf("  z1 is %g;", (float) *ptr/0x7fffffff); ptr++;
+      printf(" z2 is %g\n", (float) *ptr/0x7fffffff); ptr++;
+      printf ("   names are ");
+      for (j = 0; j < names; j++) { /*  for each name */
+         printf ("%d ", *ptr);
+         if (j == 0)  /*  set row and column  */
+            ii = *ptr;
+         else if (j == 1)
+            jj = *ptr;
+         ptr++;
+      }
+      printf ("\n");
+      board[ii][jj] = (board[ii][jj] + 1) % 3;
+   }
+}
+
+/*  pickSquares() sets up selection mode, name stack, 
+ *  and projection matrix for picking.  Then the 
+ *  objects are drawn.
+ */
+#define BUFSIZE 512
+
+void pickSquares(int button, int state, int x, int y)
+{
+   GLuint selectBuf[BUFSIZE];
+   GLint hits;
+   GLint viewport[4];
+
+   if (button != GLUT_LEFT_BUTTON || state != GLUT_DOWN)
+      return;
+
+   glGetIntegerv (GL_VIEWPORT, viewport);
+
+   glSelectBuffer (BUFSIZE, selectBuf);
+   (void) glRenderMode (GL_SELECT);
+
+   glInitNames();
+   glPushName(0);
+
+   glMatrixMode (GL_PROJECTION);
+   glPushMatrix ();
+   glLoadIdentity ();
+/*  create 5x5 pixel picking region near cursor location	*/
+   gluPickMatrix ((GLdouble) x, (GLdouble) (viewport[3] - y), 
+                  5.0, 5.0, viewport);
+   gluOrtho2D (0.0, 3.0, 0.0, 3.0);
+   drawSquares (GL_SELECT);
+
+   glMatrixMode (GL_PROJECTION);
+   glPopMatrix ();
+   glFlush ();
+
+   hits = glRenderMode (GL_RENDER);
+   processHits (hits, selectBuf);
+   glutPostRedisplay();
+} 
+
+void display(void)
+{
+   glClear(GL_COLOR_BUFFER_BIT);
+   drawSquares (GL_RENDER);
+   glFlush();
+}
+
+void reshape(int w, int h)
+{
+   glViewport(0, 0, w, h);
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+   gluOrtho2D (0.0, 3.0, 0.0, 3.0);
+   glMatrixMode(GL_MODELVIEW);
+   glLoadIdentity();
+}
+
+/* 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);
+   glutInitWindowSize (100, 100);
+   glutInitWindowPosition (100, 100);
+   glutCreateWindow (argv[0]);
+   init ();
+   glutReshapeFunc (reshape);
+   glutDisplayFunc(display); 
+   glutMouseFunc (pickSquares);
+   glutKeyboardFunc (keyboard);
+   glutMainLoop();
+   return 0; 
+}