Initial revision
diff --git a/progs/demos/gamma.c b/progs/demos/gamma.c
new file mode 100644
index 0000000..a3b0bd8
--- /dev/null
+++ b/progs/demos/gamma.c
@@ -0,0 +1,176 @@
+
+/* $Id: gamma.c,v 1.1 1999/08/19 00:55:40 jtg Exp $ */
+
+/* Draw test patterns to help determine correct gamma value for a display.
+ When the intensities of the inner squares nearly match the intensities
+ of their frames (from some distance the borders should disappear) then
+ you've found the right gamma value.
+
+ You can set Mesa's gamma values (for red, green and blue) with the
+ MESA_GAMMA environment variable. But only on X windows!
+ For example:
+ setenv MESA_GAMMA 1.5 1.6 1.4
+ Sets the red gamma value to 1.5, green to 1.6 and blue to 1.4.
+ See the main README file for more information.
+
+ For more info about gamma correction see:
+ http://www.inforamp.net/~poynton/notes/colour_and_gamma/GammaFAQ.html
+
+ This program is in the public domain
+
+ Brian Paul 19 Oct 1995
+ Kai Schuetz 05 Jun 1999 */
+
+/* Conversion to GLUT by Mark J. Kilgard */
+
+/*
+ * $Log: gamma.c,v $
+ * Revision 1.1 1999/08/19 00:55:40 jtg
+ * Initial revision
+ *
+ * Revision 3.1 1999/06/19 01:35:38 brianp
+ * merged in Kai Schuetz's RGB changes
+ *
+ * Revision 3.0 1998/02/14 18:42:29 brianp
+ * initial rev
+ *
+ */
+
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <GL/glut.h>
+
+static void
+Reshape(int width, int height)
+{
+ glViewport(0, 0, (GLint) width, (GLint) height);
+
+ glMatrixMode(GL_PROJECTION);
+ glLoadIdentity();
+ glOrtho(-1.0, 1.0, -1.0, 1.0, -1.0, 1.0);
+ glMatrixMode(GL_MODELVIEW);
+ glShadeModel(GL_FLAT);
+}
+
+/* ARGSUSED1 */
+static void
+key_esc(unsigned char key, int x, int y)
+{
+ if(key == 27) exit(0); /* Exit on Escape */
+}
+
+static GLubyte p25[] = {
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00,
+};
+
+static GLubyte p50[] = {
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
+};
+
+static GLubyte p75[] = {
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+ 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff,
+};
+
+static GLubyte *stippletab[4] = {NULL, p25, p50, p75};
+
+static void
+gamma_ramp(GLfloat yoffs, GLfloat r, GLfloat g, GLfloat b)
+{
+ GLint d;
+
+ glColor3f(0.0, 0.0, 0.0); /* solid black, no stipple */
+ glRectf(-1.0, yoffs, -0.6, yoffs + 0.5);
+
+ for(d = 1; d < 4; d++) { /* increasing density from 25% to 75% */
+ GLfloat xcoord = (-1.0 + d*0.4);
+
+ glColor3f(r*d / 5.0, g*d / 5.0, b*d / 5.0); /* draw outer rect */
+ glRectf(xcoord, yoffs, xcoord+0.4, yoffs + 0.5);
+
+ glColor3f(0.0, 0.0, 0.0); /* "clear" inner rect */
+ glRectf(xcoord + 0.1, yoffs + 0.125, xcoord + 0.3, yoffs + 0.375);
+
+ glColor3f(r, g, b); /* draw stippled inner rect */
+ glEnable(GL_POLYGON_STIPPLE);
+ glPolygonStipple(stippletab[d]);
+ glRectf(xcoord + 0.1, yoffs + 0.125, xcoord + 0.3, yoffs + 0.375);
+ glDisable(GL_POLYGON_STIPPLE);
+ }
+ glColor3f(r, g, b); /* solid color, no stipple */
+ glRectf(0.6, yoffs, 1.0, yoffs + 0.5);
+}
+
+static void
+display(void)
+{
+ gamma_ramp( 0.5, 1.0, 1.0, 1.0); /* white ramp */
+ gamma_ramp( 0.0, 1.0, 0.0, 0.0); /* red ramp */
+ gamma_ramp(-0.5, 0.0, 1.0, 0.0); /* green ramp */
+ gamma_ramp(-1.0, 0.0, 0.0, 1.0); /* blue ramp */
+ glFlush();
+}
+
+int
+main(int argc, char **argv)
+{
+ glutInit(&argc, argv);
+ glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
+
+ glutInitWindowPosition(50, 50);
+ glutInitWindowSize(500, 400);
+
+ glutCreateWindow("gamma test patterns");
+ glutReshapeFunc(Reshape);
+ glutDisplayFunc(display);
+ glutKeyboardFunc(key_esc);
+
+ glutMainLoop();
+ return 0; /* ANSI C requires main to return int. */
+}