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Diffstat (limited to 'progs/redbook/pickdepth.c')
| -rw-r--r-- | progs/redbook/pickdepth.c | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/progs/redbook/pickdepth.c b/progs/redbook/pickdepth.c new file mode 100644 index 0000000000..c6d50a91d9 --- /dev/null +++ b/progs/redbook/pickdepth.c @@ -0,0 +1,203 @@ + +/* Copyright (c) Mark J. Kilgard, 1994. */ + +/* + * (c) Copyright 1993, 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 + * Unpublished-- rights reserved under the copyright laws of the + * United States.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(TM) is a trademark of Silicon Graphics, Inc. + */ +/* + * pickdepth.c + * Picking is demonstrated in this program. In + * rendering mode, three overlapping rectangles are + * drawn. When the left mouse button is pressed, + * selection mode is entered with the picking matrix. + * Rectangles which are drawn under the cursor position + * are "picked." Pay special attention to the depth + * value range, which is returned. + */ +#include <stdlib.h> +#include <stdio.h> +#include <GL/glut.h> + +void +myinit(void) +{ + glClearColor(0.0, 0.0, 0.0, 0.0); + glDepthFunc(GL_LESS); + glEnable(GL_DEPTH_TEST); + glShadeModel(GL_FLAT); + glDepthRange(0.0, 1.0); /* The default z mapping */ +} + +/* The three rectangles are drawn. In selection mode, + * each rectangle is given the same name. Note that + * each rectangle is drawn with a different z value. + */ +void +drawRects(GLenum mode) +{ + if (mode == GL_SELECT) + glLoadName(1); + glBegin(GL_QUADS); + glColor3f(1.0, 1.0, 0.0); + glVertex3i(2, 0, 0); + glVertex3i(2, 6, 0); + glVertex3i(6, 6, 0); + glVertex3i(6, 0, 0); + glEnd(); + if (mode == GL_SELECT) + glLoadName(2); + glBegin(GL_QUADS); + glColor3f(0.0, 1.0, 1.0); + glVertex3i(3, 2, -1); + glVertex3i(3, 8, -1); + glVertex3i(8, 8, -1); + glVertex3i(8, 2, -1); + glEnd(); + if (mode == GL_SELECT) + glLoadName(3); + glBegin(GL_QUADS); + glColor3f(1.0, 0.0, 1.0); + glVertex3i(0, 2, -2); + glVertex3i(0, 7, -2); + glVertex3i(5, 7, -2); + glVertex3i(5, 2, -2); + glEnd(); +} + +/* processHits() prints out the contents of the + * selection array. + */ +void +processHits(GLint hits, GLuint buffer[]) +{ + unsigned int i, j; + GLuint 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/0xffffffff); + ptr++; + printf(" z2 is %g\n", (float) *ptr/0xffffffff); + ptr++; + printf(" the name is "); + for (j = 0; j < names; j++) { /* for each name */ + printf("%d ", *ptr); + ptr++; + } + printf("\n"); + } +} + +/* pickRects() sets up selection mode, name stack, + * and projection matrix for picking. Then the objects + * are drawn. + */ +#define BUFSIZE 512 + +void +pickRects(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(-1); + + 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); + glOrtho(0.0, 8.0, 0.0, 8.0, -0.5, 2.5); + drawRects(GL_SELECT); + glPopMatrix(); + glFlush(); + + hits = glRenderMode(GL_RENDER); + processHits(hits, selectBuf); +} + +void +display(void) +{ + glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); + drawRects(GL_RENDER); + glutSwapBuffers(); +} + +void +myReshape(int w, int h) +{ + glViewport(0, 0, w, h); + glMatrixMode(GL_PROJECTION); + glLoadIdentity(); + glOrtho(0.0, 8.0, 0.0, 8.0, -0.5, 2.5); + glMatrixMode(GL_MODELVIEW); + glLoadIdentity(); +} + +/* Main Loop + * Open window with initial window size, title bar, + * RGBA display mode, depth buffer, and handle input events. + */ +int +main(int argc, char **argv) +{ + glutInitWindowSize(200, 200); + glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH); + glutInit(&argc, argv); + glutCreateWindow(argv[0]); + myinit(); + glutMouseFunc(pickRects); + glutReshapeFunc(myReshape); + glutDisplayFunc(display); + glutMainLoop(); + return 0; /* ANSI C requires main to return int. */ +} |