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authorBrian Paul <[email protected]>2010-02-15 09:55:01 -0700
committerBrian Paul <[email protected]>2010-02-15 09:55:01 -0700
commitce65a8debe623d72cb4af142ace2be33a2fc575c (patch)
tree3e5bd22dcd76dc56a54bbc8bd759cd6488ef2212 /progs/redbook/histogram.c
parent3be1c11001be872a6850607955e61e82a470c064 (diff)
progs/redbook: add additional tests for GL 1.4
Diffstat (limited to 'progs/redbook/histogram.c')
-rw-r--r--progs/redbook/histogram.c201
1 files changed, 201 insertions, 0 deletions
diff --git a/progs/redbook/histogram.c b/progs/redbook/histogram.c
new file mode 100644
index 00000000000..7ddceb69e2e
--- /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 Unpublished - rights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;
+}