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Amiga Format CD 52
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Amiga Format AFCD52 (Issue 136, May 2000).iso
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mesa
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book.aux
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pickdepth.c
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C/C++ Source or Header
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2000-02-23
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6KB
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199 lines
/*
* (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* Unpublished-- rights reserved under the copyright laws of the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 <GL/gl.h>
#include <GL/glu.h>
#include <stdio.h>
#include <stdlib.h>
#include <GL/glaux.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);
glColor3f(0.0, 1.0, 1.0);
glVertex3i(3, 2, -1);
glVertex3i(3, 8, -1);
glVertex3i(8, 8, -1);
glVertex3i(8, 2, -1);
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 %u;", *ptr);
ptr++;
printf(" z2 is %u\n", *ptr);
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(AUX_EVENTREC * event)
{
GLuint selectBuf[BUFSIZE];
GLint hits;
GLint viewport[4];
int x, y;
x = event->data[AUX_MOUSEX];
y = event->data[AUX_MOUSEY];
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);
glFlush();
}
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)
{
auxInitDisplayMode(AUX_SINGLE | AUX_RGB | AUX_DEPTH);
auxInitPosition(0, 0, 100, 100);
if (!auxInitWindow(argv[0]))
auxQuit();
myinit();
auxMouseFunc(AUX_LEFTBUTTON, AUX_MOUSEDOWN, pickRects);
auxReshapeFunc(myReshape);
auxMainLoop(display);
return 0;
}