1 files changed, 176 insertions, 0 deletions
diff --git a/progs/demos/gamma.c b/progs/demos/gamma.c
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+
+/* $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. */
+}