/* * 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 * Unpublished-- rights reserved under the copyright laws of the * United States.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; }