Added ESC key handling

progs/redbook/fog.c

@@ -3,14 +3,14 @@
 
 /**
  * (c) Copyright 1993, Silicon Graphics, Inc.
- * ALL RIGHTS RESERVED 
- * Permission to use, copy, modify, and distribute this software for 
+ * 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 
+ * 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. 
+ * 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,
@@ -24,8 +24,8 @@
  * 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 
+ *
+ * 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
@@ -39,11 +39,11 @@
  */
 /*
  *  fog.c
- *  This program draws 5 red teapots, each at a different 
- *  z distance from the eye, in different types of fog.  
- *  Pressing the left mouse button chooses between 3 types of 
- *  fog:  exponential, exponential squared, and linear.  
- *  In this program, there is a fixed density value, as well 
+ *  This program draws 5 red teapots, each at a different
+ *  z distance from the eye, in different types of fog.
+ *  Pressing the left mouse button chooses between 3 types of
+ *  fog:  exponential, exponential squared, and linear.
+ *  In this program, there is a fixed density value, as well
  *  as fixed start and end values for the linear fog.
  */
 #include <stdlib.h>
@@ -52,7 +52,7 @@
 
 GLint fogMode;
 
-void 
+void
 selectFog(int mode)
 {
     switch(mode) {
@@ -70,10 +70,10 @@ selectFog(int mode)
     }
 }
 
-/*  Initialize z-buffer, projection matrix, light source, 
+/*  Initialize z-buffer, projection matrix, light source,
  *  and lighting model.  Do not specify a material property here.
  */
-void 
+void
 myinit(void)
 {
     GLfloat position[] =
@@ -106,7 +106,7 @@ myinit(void)
     }
 }
 
-void 
+void
 renderRedTeapot(GLfloat x, GLfloat y, GLfloat z)
 {
     float mat[4];
@@ -133,7 +133,7 @@ renderRedTeapot(GLfloat x, GLfloat y, GLfloat z)
 
 /*  display() draws 5 teapots at different z positions.
  */
-void 
+void
 display(void)
 {
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
@@ -145,7 +145,7 @@ display(void)
     glFlush();
 }
 
-void 
+void
 myReshape(int w, int h)
 {
     glViewport(0, 0, w, h);
@@ -161,11 +161,24 @@ myReshape(int w, int h)
     glLoadIdentity();
 }
 
+static void
+key(unsigned char k, int x, int y)
+{
+  switch (k) {
+  case 27:  /* Escape */
+    exit(0);
+    break;
+  default:
+    return;
+  }
+  glutPostRedisplay();
+}
+
 /*  Main Loop
- *  Open window with initial window size, title bar, 
+ *  Open window with initial window size, title bar,
  *  RGBA display mode, depth buffer, and handle input events.
  */
-int 
+int
 main(int argc, char **argv)
 {
     glutInit(&argc, argv);
@@ -181,6 +194,7 @@ main(int argc, char **argv)
     glutAddMenuEntry("Fog LINEAR", GL_LINEAR);
     glutAddMenuEntry("Quit", 0);
     glutAttachMenu(GLUT_RIGHT_BUTTON);
+    glutKeyboardFunc(key);
     glutMainLoop();
     return 0;             /* ANSI C requires main to return int. */
 }