diff options
Diffstat (limited to 'progs/redbook/histogram.c')
-rw-r--r-- | progs/redbook/histogram.c | 7 |
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); |