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Diffstat (limited to 'progs/redbook/picksquare.c')
| -rw-r--r-- | progs/redbook/picksquare.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/progs/redbook/picksquare.c b/progs/redbook/picksquare.c new file mode 100644 index 0000000000..0a12aa0fac --- /dev/null +++ b/progs/redbook/picksquare.c @@ -0,0 +1,197 @@ +/* + * 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 + * Unpublished-- rights reserved under the copyright laws of the + * United States.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; +} |