1 files changed, 201 insertions, 0 deletions
diff --git a/progs/redbook/histogram.c b/progs/redbook/histogram.c
new file mode 100644
index 0000000000..7ddceb69e2
--- /dev/null
+++ b/progs/redbook/histogram.c
@@ -0,0 +1,201 @@
+/*
+ * 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  Unpublished - rights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.
+ */
+
+/*
+ *  histogram.c
+ *  Compute the histogram of the image.  This program illustrates the
+ *  use of the glHistogram() function.
+ */
+
+#include <GL/glut.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#define HISTOGRAM_SIZE  256   /* Must be a power of 2 */
+
+
+static GLubyte  *pixels;
+static GLsizei   width, height;
+
+
+
+static GLuint bswap(GLuint x)
+{
+   const GLuint ui = 1;
+   const GLubyte *ubp = (const GLubyte *) &ui;
+   if (*ubp == 1) {
+      /* we're on little endiang so byteswap x */
+      GLsizei y =  ((x >> 24)
+                    | ((x >> 8) & 0xff00)
+                    | ((x << 8) & 0xff0000)
+                    | ((x << 24) & 0xff000000));
+      return y;
+   }
+   else {
+      return x;
+   }
+}
+
+
+static GLubyte*
+readImage( const char* filename, GLsizei* width, GLsizei *height )
+{
+    int       n;
+    GLubyte*  pixels;
+
+    FILE* infile = fopen( filename, "rb" );
+
+    if ( !infile ) {
+	fprintf( stderr, "Unable to open file '%s'\n", filename );
+        exit(1);
+    }
+
+    fread( width, sizeof( GLsizei ), 1, infile );
+    fread( height, sizeof( GLsizei ), 1, infile );
+
+    *width = bswap(*width);
+    *height = bswap(*height);
+
+    n = 3 * (*width) * (*height);
+
+    pixels = (GLubyte *) malloc( n * sizeof( GLubyte ));
+    if ( !pixels ) {
+	fprintf( stderr, "Unable to malloc() bytes for pixels\n" );
+	return NULL;
+    }
+
+    fread( pixels, sizeof( GLubyte ), n, infile );
+    
+    fclose( infile );
+
+    return pixels;
+}
+
+static void init(void)
+{
+   glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+   glClearColor(0.0, 0.0, 0.0, 0.0);
+
+   glHistogram(GL_HISTOGRAM, HISTOGRAM_SIZE, GL_RGB, GL_FALSE);
+   glEnable(GL_HISTOGRAM);
+}
+
+static void display(void)
+{
+   int i;
+   GLushort values[HISTOGRAM_SIZE][3];
+   
+   glClear(GL_COLOR_BUFFER_BIT);
+   glRasterPos2i(1, 1);
+   glDrawPixels(width, height, GL_RGB, GL_UNSIGNED_BYTE, pixels);
+   
+   glGetHistogram(GL_HISTOGRAM, GL_TRUE, GL_RGB, GL_UNSIGNED_SHORT, values);
+
+   /* Plot histogram */
+   
+   glBegin(GL_LINE_STRIP);
+   glColor3f(1.0, 0.0, 0.0);
+   for ( i = 0; i < HISTOGRAM_SIZE; i++ )
+       glVertex2s(i, values[i][0]);
+   glEnd();
+
+   glBegin(GL_LINE_STRIP);
+   glColor3f(0.0, 1.0, 0.0);
+   for ( i = 0; i < HISTOGRAM_SIZE; i++ )
+       glVertex2s(i, values[i][1]);
+   glEnd();
+
+   glBegin(GL_LINE_STRIP);
+   glColor3f(0.0, 0.0, 1.0);
+   for ( i = 0; i < HISTOGRAM_SIZE; i++ )
+       glVertex2s(i, values[i][2]);
+   glEnd();
+   glFlush();
+}
+
+static void reshape(int w, int h)
+{
+   glViewport(0, 0, (GLsizei) w, (GLsizei) h);
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+   glOrtho(0, 256, 0, 10000, -1.0, 1.0);
+   glMatrixMode(GL_MODELVIEW);
+}
+
+static void keyboard(unsigned char key, int x, int y)
+{
+   static GLboolean sink = GL_FALSE;
+    
+   switch (key) {
+      case 's' :
+	  sink = !sink;
+	  glHistogram(GL_HISTOGRAM, HISTOGRAM_SIZE, GL_RGB, sink);
+	  break;
+	  
+      case 27:
+         exit(0);
+   }
+   glutPostRedisplay();
+   
+}
+
+/*  Main Loop
+ *  Open window with initial window size, title bar, 
+ *  RGBA display mode, and handle input events.
+ */
+int main(int argc, char** argv)
+{
+   pixels = readImage("leeds.bin", &width, &height);    
+
+   glutInit(&argc, argv);
+   glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
+   glutInitWindowSize(width, height);
+   glutInitWindowPosition(100, 100);
+   glutCreateWindow(argv[0]);
+   init();
+   glutReshapeFunc(reshape);
+   glutKeyboardFunc(keyboard);
+   glutDisplayFunc(display);
+   glutMainLoop();
+   return 0;
+}