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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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ohidden.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.
*/
/*----------------------------------------------------------------------------
*
* ohidden.c : openGL (motif) example showing how to use stencils
* to draw outlined polygons.
*
* Author : Yusuf Attarwala
* SGI - Applications
* Date : Jul 93
*
* note : the main intent of this program is to demo the stencil
* plane functionality, hence the rendering is kept
* simple (wireframe).
*
* press left button for animation
* press middle button to turn OFF stenciling
* press right button to turn ON stenciling
*
*---------------------------------------------------------------------------*/
#include <stdio.h>
#include <stdlib.h>
#include <string.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 */
static int stencilOn = 1;
/* function declarations */
void
createToplevel(void),
drawScene(void),
setMatrix(void),
animation(void),
exposeCB(Widget,XtPointer,XtPointer),
resizeCB(Widget,XtPointer,XtPointer),
initCB(Widget,XtPointer,XtPointer),
inputCB(Widget,XtPointer,XtPointer),
drawWireframe(int face),
drawFilled(int face);
/* global variables */
Display *display; /* current display */
XtAppContext appContext; /* X application context */
float ax,ay,az; /* angles for animation */
Widget toplevel, /* toplevel shell */
glw; /* current widget */
GLXContext glxc; /* current glx context */
Arg args[20];
int acnt;
/* coords of a cube */
static GLfloat cube[8][3] = {0.0,0.0,0.0,
1.0,0.0,0.0,
1.0,0.0,1.0,
0.0,0.0,1.0,
1.0,1.0,0.0,
1.0,1.0,1.0,
0.0,1.0,1.0,
0.0,1.0,0.0};
static int faceIndex[6][4] = {0,1,2,3,
1,4,5,2,
4,7,6,5,
7,0,3,6,
3,2,5,6,
7,4,1,0};
void
main(int argc, char** argv)
{
XtToolkitInitialize();
appContext = XtCreateApplicationContext();
display = XtOpenDisplay(appContext, NULL, "Ostencil","ostencil",NULL,0,
&argc,argv);
if (!display) {
printf("%s : Unable to open display\n",argv[0]);
exit(0);
}
printf("\n---------------------------------------------\n");
printf("OpenGL stencil example \n\n");
printf("Press: left button for animation\n\
middle button to turn OFF stenciling\n\
right button to turn ON stenciling (default)\n");
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 stencil","ostencil",
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], GLwNstencilSize, 1); 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);
}
static float p0[] = {-5.0,-5.0,0.0};
static float p1[] = {5.0,-5.0,0.0};
static float p2[] = {5.0,5.0,0.0};
static float p3[] = {-5.0,5.0,0.0};
void
drawWireframe(face)
int face;
{
int i;
glBegin(GL_LINE_LOOP);
for (i=0;i<4;i++)
glVertex3fv((GLfloat *)cube[faceIndex[face][i]]);
glEnd();
}
void
drawFilled(face)
int face;
{
int i;
glBegin(GL_POLYGON);
for (i=0;i<4;i++)
glVertex3fv((GLfloat *)cube[faceIndex[face][i]]);
glEnd();
}
void
drawScene(void)
{
int i;
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glClearColor(0.0, 0.0, 0.0, 0.0);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glRotatef (ax,1.0,0.0,0.0);
glRotatef (-ay,0.0, 1.0, 0.0);
/* all the good stuff follows */
if (stencilOn) {
glEnable(GL_STENCIL_TEST);
glClear(GL_STENCIL_BUFFER_BIT);
glStencilMask(1);
glStencilFunc(GL_ALWAYS,0,1);
glStencilOp(GL_INVERT, GL_INVERT, GL_INVERT);
}
glColor3f (1.0, 1.0, 0.0);
for (i=0;i<6;i++) {
drawWireframe(i);
if (stencilOn) {
glStencilFunc(GL_EQUAL, 0, 1);
glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
}
glColor3f (0.0, 0.0, 0.0);
drawFilled(i);
glColor3f (1.0, 1.0, 0.0);
if (stencilOn) {
glStencilFunc(GL_ALWAYS,0,1);
glStencilOp(GL_INVERT, GL_INVERT, GL_INVERT);
}
glColor3f (1.0, 1.0, 0.0);
drawWireframe(i);
}
glPopMatrix();
if (stencilOn) glDisable(GL_STENCIL_TEST);
/* end of good stuff */
glFlush();
glXSwapBuffers(XtDisplay(glw), XtWindow(glw));
}
void
setMatrix(void)
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-2.0,2.0,-2.0,2.0,-2.0,2.0);
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
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 :
stencilOn = 0;
XtVaSetValues(toplevel,XmNtitle, "Stencil Disabled",NULL);
drawScene();
break;
case Button3 :
stencilOn = 1;
XtVaSetValues(toplevel,XmNtitle, "Stencil Enabled",NULL);
drawScene();
break;
}
break;
case KeyPress :
XLookupString((XKeyEvent *)call_data->event,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;
}