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diff --git a/progs/redbook/shadowmap.c b/progs/redbook/shadowmap.c
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+/*
+ * Copyright (c) 1993-2003, 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 Unpublished - rights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.
+ * 1500 Crittenden Lane
+ * Mountain View, CA 94043
+ * United State of America
+ *
+ * OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
+ */
+
+#define GL_GLEXT_PROTOTYPES
+
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <GL/glut.h>
+/*#include "helpers.h"*/
+
+#define SHADOW_MAP_WIDTH 256
+#define SHADOW_MAP_HEIGHT 256
+
+#define PI 3.14159265359
+
+GLdouble fovy = 60.0;
+GLdouble nearPlane = 10.0;
+GLdouble farPlane = 100.0;
+
+GLfloat angle = 0.0;
+GLfloat torusAngle = 0.0;
+
+GLfloat lightPos[] = { 25.0, 25.0, 25.0, 1.0 };
+GLfloat lookat[] = { 0.0, 0.0, 0.0 };
+GLfloat up[] = { 0.0, 0.0, 1.0 };
+
+GLboolean showShadow = GL_FALSE;
+
+static void
+init( void )
+{
+ GLfloat white[] = { 1.0, 1.0, 1.0, 1.0 };
+
+ glTexImage2D( GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT,
+ SHADOW_MAP_WIDTH, SHADOW_MAP_HEIGHT, 0,
+ GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, NULL );
+
+ glLightfv( GL_LIGHT0, GL_POSITION, lightPos );
+ glLightfv( GL_LIGHT0, GL_SPECULAR, white );
+ glLightfv( GL_LIGHT0, GL_DIFFUSE, white );
+
+ glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
+ glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
+ glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
+ glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
+ glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL );
+ glTexParameteri( GL_TEXTURE_2D, GL_DEPTH_TEXTURE_MODE, GL_LUMINANCE );
+ glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE,
+ GL_COMPARE_R_TO_TEXTURE );
+
+ glTexGeni( GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
+ glTexGeni( GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
+ glTexGeni( GL_R, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
+ glTexGeni( GL_Q, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
+
+ glColorMaterial( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE );
+
+ glCullFace( GL_BACK );
+
+ glEnable( GL_DEPTH_TEST );
+ glEnable( GL_LIGHT0 );
+ glEnable( GL_LIGHTING );
+ glEnable( GL_TEXTURE_2D );
+ glEnable( GL_TEXTURE_GEN_S );
+ glEnable( GL_TEXTURE_GEN_T );
+ glEnable( GL_TEXTURE_GEN_R );
+ glEnable( GL_TEXTURE_GEN_Q );
+ glEnable( GL_COLOR_MATERIAL );
+ glEnable( GL_CULL_FACE );
+}
+
+static void
+reshape( int width, int height )
+{
+ glViewport( 0, 0, width, height );
+
+ glMatrixMode( GL_PROJECTION );
+ glLoadIdentity();
+ gluPerspective( fovy, (GLdouble) width/height, nearPlane, farPlane );
+ glMatrixMode( GL_MODELVIEW );
+}
+
+static void
+idle( void )
+{
+ angle += PI / 10000;
+ torusAngle += .1;
+ glutPostRedisplay();
+}
+
+static void
+keyboard( unsigned char key, int x, int y )
+{
+ switch( key ) {
+ case 27: /* Escape */
+ exit( 0 );
+ break;
+
+ case 't': {
+ static GLboolean textureOn = GL_TRUE;
+ textureOn = !textureOn;
+ if ( textureOn )
+ glEnable( GL_TEXTURE_2D );
+ else
+ glDisable( GL_TEXTURE_2D );
+ }
+ break;
+
+ case 'm': {
+ static GLboolean compareMode = GL_TRUE;
+ compareMode = !compareMode;
+ printf( "Compare mode %s\n", compareMode ? "On" : "Off" );
+ glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE,
+ compareMode ? GL_COMPARE_R_TO_TEXTURE : GL_NONE );
+ }
+ break;
+
+ case 'f': {
+ static GLboolean funcMode = GL_TRUE;
+ funcMode = !funcMode;
+ printf( "Operator %s\n", funcMode ? "GL_LEQUAL" : "GL_GEQUAL" );
+ glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC,
+ funcMode ? GL_LEQUAL : GL_GEQUAL );
+ }
+ break;
+
+ case 's':
+ showShadow = !showShadow;
+ break;
+
+ case 'p': {
+ static GLboolean animate = GL_TRUE;
+ animate = !animate;
+ glutIdleFunc( animate ? idle : NULL );
+ }
+ break;
+ }
+
+ glutPostRedisplay();
+}
+
+static void
+transposeMatrix( GLfloat m[16] )
+{
+ GLfloat tmp;
+#define Swap( a, b ) tmp = a; a = b; b = tmp
+ Swap( m[1], m[4] );
+ Swap( m[2], m[8] );
+ Swap( m[3], m[12] );
+ Swap( m[6], m[9] );
+ Swap( m[7], m[13] );
+ Swap( m[11], m[14] );
+#undef Swap
+}
+
+static void
+drawObjects( GLboolean shadowRender )
+{
+ GLboolean textureOn = glIsEnabled( GL_TEXTURE_2D );
+
+ if ( shadowRender )
+ glDisable( GL_TEXTURE_2D );
+
+ if ( !shadowRender ) {
+ glNormal3f( 0, 0, 1 );
+ glColor3f( 1, 1, 1 );
+ glRectf( -20.0, -20.0, 20.0, 20.0 );
+ }
+
+ glPushMatrix();
+ glTranslatef( 11, 11, 11 );
+ glRotatef( 54.73, -5, 5, 0 );
+ glRotatef( torusAngle, 1, 0, 0 );
+ glColor3f( 1, 0, 0 );
+ glutSolidTorus( 1, 4, 8, 36 );
+ glPopMatrix();
+
+ glPushMatrix();
+ glTranslatef( 2, 2, 2 );
+ glColor3f( 0, 0, 1 );
+ glutSolidCube( 4 );
+ glPopMatrix();
+
+ glPushMatrix();
+ glTranslatef( lightPos[0], lightPos[1], lightPos[2] );
+ glColor3f( 1, 1, 1 );
+ glutWireSphere( 0.5, 6, 6 );
+ glPopMatrix();
+
+ if ( shadowRender && textureOn )
+ glEnable( GL_TEXTURE_2D );
+}
+
+static void
+generateShadowMap( void )
+{
+ GLint viewport[4];
+ GLfloat lightPos[4];
+
+ glGetLightfv( GL_LIGHT0, GL_POSITION, lightPos );
+ glGetIntegerv( GL_VIEWPORT, viewport );
+
+ glViewport( 0, 0, SHADOW_MAP_WIDTH, SHADOW_MAP_HEIGHT );
+
+ glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
+
+ glMatrixMode( GL_PROJECTION );
+ glPushMatrix();
+ glLoadIdentity();
+ gluPerspective( 80.0, 1.0, 10.0, 1000.0 );
+ glMatrixMode( GL_MODELVIEW );
+
+ glPushMatrix();
+ glLoadIdentity();
+ gluLookAt( lightPos[0], lightPos[1], lightPos[2],
+ lookat[0], lookat[1], lookat[2],
+ up[0], up[1], up[2] );
+
+ drawObjects( GL_TRUE );
+
+ glPopMatrix();
+ glMatrixMode( GL_PROJECTION );
+ glPopMatrix();
+ glMatrixMode( GL_MODELVIEW );
+
+ glCopyTexImage2D( GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, 0, 0,
+ SHADOW_MAP_WIDTH, SHADOW_MAP_HEIGHT, 0 );
+
+ glViewport( viewport[0], viewport[1], viewport[2], viewport[3] );
+
+ if ( showShadow ) {
+ GLfloat depthImage[SHADOW_MAP_WIDTH][SHADOW_MAP_HEIGHT];
+ glReadPixels( 0, 0, SHADOW_MAP_WIDTH, SHADOW_MAP_HEIGHT,
+ GL_DEPTH_COMPONENT, GL_FLOAT, depthImage );
+ glWindowPos2f( viewport[2]/2, 0 );
+ glDrawPixels( SHADOW_MAP_WIDTH, SHADOW_MAP_HEIGHT, GL_LUMINANCE,
+ GL_FLOAT, depthImage );
+ glutSwapBuffers();
+ }
+}
+
+static void
+generateTextureMatrix( void )
+{
+ GLfloat tmpMatrix[16];
+
+ /*
+ * Set up projective texture matrix. We use the GL_MODELVIEW matrix
+ * stack and OpenGL matrix commands to make the matrix.
+ */
+ glPushMatrix();
+ glLoadIdentity();
+ glTranslatef( 0.5, 0.5, 0.0 );
+ glScalef( 0.5, 0.5, 1.0 );
+ gluPerspective( 60.0, 1.0, 1.0, 1000.0 );
+ gluLookAt( lightPos[0], lightPos[1], lightPos[2],
+ lookat[0], lookat[1], lookat[2],
+ up[0], up[1], up[2] );
+ glGetFloatv( GL_MODELVIEW_MATRIX, tmpMatrix );
+ glPopMatrix();
+
+ transposeMatrix( tmpMatrix );
+
+ glTexGenfv( GL_S, GL_OBJECT_PLANE, &tmpMatrix[0] );
+ glTexGenfv( GL_T, GL_OBJECT_PLANE, &tmpMatrix[4] );
+ glTexGenfv( GL_R, GL_OBJECT_PLANE, &tmpMatrix[8] );
+ glTexGenfv( GL_Q, GL_OBJECT_PLANE, &tmpMatrix[12] );
+}
+
+static void
+display( void )
+{
+ GLfloat radius = 30;
+
+ generateShadowMap();
+ generateTextureMatrix();
+
+ if ( showShadow )
+ return;
+
+ glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
+
+ glPushMatrix();
+ gluLookAt( radius*cos(angle), radius*sin(angle), 30,
+ lookat[0], lookat[1], lookat[2],
+ up[0], up[1], up[2] );
+ drawObjects( GL_FALSE );
+ glPopMatrix();
+
+ glutSwapBuffers();
+}
+
+int
+main( int argc, char** argv )
+{
+ glutInit( &argc, argv );
+ glutInitDisplayMode( GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE );
+ glutInitWindowSize( 512, 512 );
+ glutInitWindowPosition( 100, 100 );
+ glutCreateWindow( argv[0] );
+
+ init();
+
+ glutDisplayFunc( display );
+ glutReshapeFunc( reshape );
+ glutKeyboardFunc( keyboard );
+ glutIdleFunc( idle );
+
+ glutMainLoop();
+
+ return 0;
+}
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