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-rw-r--r--progs/redbook/histogram.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/progs/redbook/histogram.c b/progs/redbook/histogram.c
index 7ddceb69e2..de1e59edea 100644
--- a/progs/redbook/histogram.c
+++ b/progs/redbook/histogram.c
@@ -46,6 +46,7 @@
* use of the glHistogram() function.
*/
+#include <GL/glew.h>
#include <GL/glut.h>
#include <assert.h>
#include <stdlib.h>
@@ -113,6 +114,11 @@ readImage( const char* filename, GLsizei* width, GLsizei *height )
static void init(void)
{
+ if (!glutExtensionSupported("GL_ARB_imaging")) {
+ fprintf(stderr, "Sorry, this program requires GL_ARB_imaging.\n");
+ exit(1);
+ }
+
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glClearColor(0.0, 0.0, 0.0, 0.0);
@@ -192,6 +198,7 @@ int main(int argc, char** argv)
glutInitWindowSize(width, height);
glutInitWindowPosition(100, 100);
glutCreateWindow(argv[0]);
+ glewInit();
init();
glutReshapeFunc(reshape);
glutKeyboardFunc(keyboard);