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SGI Developer Toolbox 6.1
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SGI Developer Toolbox 6.1 - Disc 1.iso
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toolbox
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src
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exampleCode
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opengl
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motif
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oclip.c
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1996-11-11
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/*
* Copyright (c) 1993-94, Silicon Graphics, Inc.
*
* Permission to use, copy, modify, distribute, and sell this software and
* its documentation for any purpose is hereby granted without fee, provided
* that the name of Silicon Graphics may not be used in any advertising or
* publicity relating to the software without the specific, prior written
* permission of Silicon Graphics.
*
* THE SOFTWARE IS PROVIDED "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 BE LIABLE FOR ANY SPECIAL, INCIDENTAL,
* INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, OR ANY DAMAGES WHATSOEVER
* RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER OR NOT ADVISED OF THE
* POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF LIABILITY, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* OpenGL(TM) is a trademark of Silicon Graphics, Inc.
*/
/*----------------------------------------------------------------------------
*
* oclip.c : openGL (motif) example showing how to use arbitrary clipping plane.
*
* Author : Yusuf Attarwala
* SGI - Applications
* Date : Mar 93
*
* note : the main intent of this program is to demo the arbitrary
* clipping functionality, hence the rendering is kept
* simple (wireframe) and only one clipping plane is used.
*
* press left button to move object
* right button to move clipping plane
*
*
*---------------------------------------------------------------------------*/
#include <stdio.h>
#include <stdlib.h>
#include <Xm/Xm.h>
#include <Xm/Frame.h> /* for frame widgets */
#include <Xm/Form.h> /* for frame widgets */
#include <X11/keysym.h> /* keyboard translations */
#include <X11/StringDefs.h>
#include <GL/gl.h> /* gl includes */
#include <GL/glu.h> /* utility library includes */
#include <GL/GLwMDrawA.h> /* include for the drawing area widget */
/* function declarations */
void
createToplevel(void),
drawScene(void),
setMatrix(void),
animateClipPlane(void),
animation(void),
exposeCB(Widget,XtPointer,XtPointer),
resizeCB(Widget,XtPointer,XtPointer),
initCB(Widget,XtPointer,XtPointer),
inputCB(Widget,XtPointer,XtPointer);
/* global variables */
Display *display; /* current display */
XtAppContext appContext; /* X application context */
float ax,ay,az; /* angles for animation */
GLUquadricObj *quadObj; /* used in drawscene */
GLdouble planeEqn[] = {0.707,0.707,0.0,0.0}; /* initial clipping plane eqn */
Widget toplevel, /* toplevel shell */
glw; /* current widget */
GLXContext glxc; /* current glx context */
Arg args[20];
int acnt;
void
main(int argc, char** argv)
{
XtToolkitInitialize();
appContext = XtCreateApplicationContext();
display = XtOpenDisplay(appContext, NULL, "Oclip","oclip",NULL,0,
&argc,argv);
if (!display) {
printf("%s : Unable to open display\n",argv[0]);
exit(0);
}
printf("\n---------------------------------------------\n");
printf("OpenGL arbitrary clipping plane example \n\n");
printf("Press: left button to move object\n\
right button to move clipping plane\n");
quadObj = gluNewQuadric (); /* this will be used in drawScene */
createToplevel(); /* create widget hierarchy */
XtAppMainLoop(appContext); /* loop forever */
}
void
createToplevel(void)
{
Widget frame;
acnt = 0;
XtSetArg(args[acnt],XmNminHeight, 300);acnt++;
XtSetArg(args[acnt],XmNminWidth, 300);acnt++;
XtSetArg(args[acnt],XmNminAspectX, 1);acnt++;
XtSetArg(args[acnt],XmNminAspectY, 1);acnt++;
XtSetArg(args[acnt],XmNmaxAspectX, 1);acnt++;
XtSetArg(args[acnt],XmNmaxAspectY, 1);acnt++;
toplevel = XtAppCreateShell("openGL clip","xtext",
applicationShellWidgetClass,
display,args,acnt);
/* create a frame to hold glx widget */
frame = XtVaCreateManagedWidget("frame",
xmFrameWidgetClass, toplevel,
NULL);
/* create a double buffer widget, in rgb mode and manage it */
acnt = 0;
XtSetArg(args[acnt], GLwNrgba, TRUE); acnt++;
XtSetArg(args[acnt], GLwNdoublebuffer, TRUE); acnt++;
XtSetArg(args[acnt], GLwNallocateBackground, TRUE); acnt++;
glw = GLwCreateMDrawingArea(frame, "glw", args, acnt);
XtManageChild(glw);
/* register callbacks */
XtAddCallback(glw, GLwNginitCallback, initCB, NULL);
/* realize widget hierarchy */
XtRealizeWidget(toplevel);
/* additional callbacks */
XtAddCallback(glw, GLwNexposeCallback, exposeCB, NULL);
XtAddCallback(glw, GLwNresizeCallback, resizeCB, NULL);
XtAddCallback(glw, GLwNinputCallback, inputCB, NULL);
}
void
drawScene(void)
{
glClearColor(0.0, 0.0, 0.0, 0.0);
glClear(GL_COLOR_BUFFER_BIT);
glPushMatrix();
gluQuadricDrawStyle (quadObj, GLU_LINE);
glColor3f (1.0, 1.0, 0.0);
glRotatef (ax,1.0,0.0,0.0);
glRotatef (-ay,0.0, 1.0, 0.0);
glClipPlane(GL_CLIP_PLANE0,planeEqn); /* define clipping plane */
glEnable(GL_CLIP_PLANE0); /* and enable it */
gluCylinder (quadObj, 2.0,5.0,10.0,20,8); /* draw a cone */
glDisable(GL_CLIP_PLANE0);
glPopMatrix();
glFlush();
glXSwapBuffers(XtDisplay(glw), XtWindow(glw));
}
void
setMatrix(void)
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-15.0,15.0,-15.0,15.0,-10.0,10.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
void
animation(void)
{
register int i;
/* animate the cone */
for (i=0;i<60;i++) {
ax += 5.0;
ay -= 2.0;
az += 5.0;
if (ax >= 360) ax = 0.0;
if (ay <= -360) ay = 0.0;
if (az >= 360) az = 0.0;
drawScene();
}
}
void
animateClipPlane(void)
{
register int i;
static int sign = 1;
for (i=0;i<5;i++) {
planeEqn[3] += sign*0.5;
if (planeEqn[3] > 4.0) sign = -1;
else if (planeEqn[3] < -4.0) sign = 1;
drawScene();
}
}
void
inputCB(Widget w, XtPointer client_data, XtPointer call)
{
char string[31];
XComposeStatus composeStatus;
KeySym keysym;
GLwDrawingAreaCallbackStruct *call_data;
call_data = (GLwDrawingAreaCallbackStruct *) call;
switch(call_data->event->type) {
case ButtonPress:
switch (call_data->event->xbutton.button) {
case Button1:
animation();
break;
case Button2 :
printf("I (button2) don't do anything\n");
break;
case Button3 :
animateClipPlane();
break;
}
break;
case KeyPress :
XLookupString(&call_data->event->xkey,string,
30,&keysym,&composeStatus);
switch(keysym) {
case XK_Escape :
exit(0);
break;
}
break;
default:
break;
}
}
void
resizeCB(Widget w, XtPointer client_data, XtPointer call)
{
GLwDrawingAreaCallbackStruct *call_data;
call_data = (GLwDrawingAreaCallbackStruct *) call;
GLwDrawingAreaMakeCurrent(w, glxc);
glViewport(0, 0, call_data->width, call_data->height);
setMatrix();
drawScene();
}
void
exposeCB(Widget w, XtPointer client_data, XtPointer call)
{
GLwDrawingAreaCallbackStruct *call_data;
call_data = (GLwDrawingAreaCallbackStruct *) call;
GLwDrawingAreaMakeCurrent(w, glxc);
glViewport(0, 0, call_data->width, call_data->height);
drawScene();
}
void
initCB(Widget w, XtPointer client_data, XtPointer call)
{
XVisualInfo *vi;
XtSetArg(args[0], GLwNvisualInfo, &vi);
XtGetValues(w, args, 1);
glxc = glXCreateContext(XtDisplay(w), vi, 0, GL_TRUE);
ax = 10.0;
ay = -10.0;
az = 0.0;
}